This diagnostic protocol was adopted by the Fifth Session of the Commission on Phytosanitary Measures in March 2010.
The annex is a prescriptive part of ISPM 27:2006.
INTERNATIONAL STANDARDS FOR PHYTOSANITARY MEASURES
ISPM 27
Annex 1
ISPM 27 DIAGNOSTIC PROTOCOLS
DP 1:
Thrips palmi Karny
(2010)
CONTENTS
1. Pest Information ..................................................................................................................... DP 1-2
2. Taxonomic Information .......................................................................................................... DP 1-3
3. Detection ................................................................................................................................. DP 1-3
4. Identification ........................................................................................................................... DP 1-4
4.1 Morphological identification of the adult thrips ...................................................... DP 1-5
4.1.1 Preparation of thrips for microscopic examination ................................................. DP 1-5
4.1.2 Identification of the family Thripidae ..................................................................... DP 1-5
4.1.3 Identification of the genus Thrips ........................................................................... DP 1-5
4.1.4 Identification of Thrips palmi ................................................................................. DP 1-7
4.1.4.1 Morphological characteristics of Thrips palmi ....................................................... DP 1-7
4.1.4.2 Comparison with similar species (species that are yellow without darker body
markings, or predominantly yellow, or sometimes yellow) .................................... DP 1-8
4.2 Molecular assays for identifying Thrips palmi ...................................................... DP 1-16
4.2.1 SCAR marker-generated sequence-based real-time PCR assay for Thrips palmi . DP 1-16
4.2.2 COI sequence-based real-time PCR assay for Thrips palmi ................................. DP 1-17
4.2.3 ITS2 sequence-based PCR-RFLP assay for nine species of thrips including Thrips
palmi ...................................................................................................................... DP 1-17
4.2.4 COI sequence-based PCR-RFLP assay for ten species of thrips including Thrips
palmi ...................................................................................................................... DP 1-18
5. Records ................................................................................................................................. DP 1-19
6. Contact points for further information .................................................................................. DP 1-19
7. Acknowledgements .............................................................................................................. DP 1-19
8. References ............................................................................................................................ DP 1-19
1. Pest Information
Thrips palmi Karny (Thysanoptera: Thripidae) is a polyphagous plant pest, especially of species in the
Cucurbitaceae and Solanaceae. It appears to have originated in Southern Asia and to have spread from
there during the latter part of the twentieth century. It has been recorded throughout Asia and is
widespread throughout the Pacific and the Caribbean. It has been recorded locally in North, Central
and South America and Africa. For more general information about T. palmi, see EPPO/CABI (1997)
or Murai (2002); online pest data sheets are also available from the Pests and Diseases Image Library
(PaDIL, 2007) and EPPO (EPPO, 2008).
The species causes economic damage to plant crops both as a direct result of its feeding activity and
from its ability to vector tospoviruses such as Groundnut bud necrosis virus, Melon yellow spot virus
and Watermelon silver mottle virus. It is extremely polyphagous, and has been recorded from more
than 36 plant families. It is an outdoor pest of, amongst others, Benincasa hispida, Capsicum annuum,
Citrullus lanatus, Cucumis melo, Cucumis sativus, Cucurbita spp., Glycine max, Gossypium spp.,
Helianthus annuus, Nicotiana tabacum, Phaseolus vulgaris, Pisum sativum, Sesamum indicum,
Solanum melongena, Solanum tuberosum and Vigna unguiculata. In glasshouses, economically
important hosts are Capsicum annuum, Chrysanthemum spp., Cucumis sativus, Cyclamen spp., Ficus
spp., Orchidaceae and Solanum melongena. The thrips may be carried on plants for planting, cut
flowers and fruits of host species, as well as on or associated with packing material, and in soil.
Thrips palmi is almost entirely yellow in coloration (Figures 1–3), and its identification is hampered
by both its small size (1.0–1.3 mm) and its great similarity to certain other yellow or predominantly
yellow species of Thrips.
Figure 1: Thrips palmi, female (left) and male (photo: A. J. M. Loomans, PPS, Wageningen, the Netherlands;
scale bar = 500 μm = 0.5 mm)
Figure 2: Thrips palmi, female
Figure 3: Thrips palmi, male
(Photos: W. Zijlstra, PPS, Wageningen, the Netherlands; scale bars: 300 μm)
2. Taxonomic Information
Name: Thrips palmi Karny, 1925
Synonyms: Thrips clarus Moulton, 1928
Thrips leucadophilus Priesner, 1936
Thrips gossypicola Ramakrishna & Margabandhu, 1939
Chloethrips aureus Ananthakrishnan & Jagadish, 1967
Thrips gracilis Ananthakrishnan & Jagadish, 1968
Taxonomic position: Insecta, Thysanoptera, Terebrantia, Thripidae
Common name: melon thrips
3. Detection
Thrips palmi may be found in different locations depending on the life stages present.
eggs in the leaf, flower and fruit tissue
larva I on the leaves, flowers and fruits
larva II on the leaves, flowers and fruits
pupa I in the soil, packing cases and growing medium
pupa II in the soil, packing cases and growing medium
adult on the leaves, flowers and fruits
On plant material, T. palmi may potentially be found on most above-ground parts of the plant; the
parts of the plant infested can differ according to variables such as the host and the characteristics of
each separate T. palmi population.
During visual examination of plant material for the presence of T. palmi, attention must be paid to
silvery feeding scars on the leaf surfaces of host plants, especially alongside the midrib and the veins.
Heavily infested plants are often characterized by a silvered or bronzed appearance of the leaves,
stunted leaves and terminals, or scarred and deformed fruits. Detection may be hampered in
circumstances such as:
- low-level infestation, which may produce little or no detectable symptoms
- the presence of the eggs within the plant tissue only (for example after external treatment which
may have removed visible life stages).
Specimens for morphological examination are best collected in a fluid called AGA, which is a mixture
of 10 parts of 60% ethanol with 1 part of glycerine and 1 part of acetic acid. If the specimens are to be
stored, they should be transferred to 60% ethanol and kept in the dark, preferably in a freezer to
prevent loss of colour. However, several laboratories have reported that AGA may act to denature the
DNA of the thrips thereby hindering any subsequent molecular work. An alternative is to use 80–95%
ethanol as the collecting fluid as any unmounted specimens may then be used for molecular studies.
However, in this case specimens must be stored in the freezer until used, or they may prove difficult to
slide mount.
Several methods can be used to collect thrips specimens (Mantel and Vierbergen, 1996; modified):
- Thrips may be individually removed from the plant (leaves, flowers or fruit), and transferred
into microtubes containing AGA, using a moist, fine brush.
- Thrips may be beaten from plant parts onto a small plastic tray (e.g. a white tray for darkcoloured
specimens or a black tray for light-coloured specimens). In cooler conditions, the
thrips usually start walking across the tray rather than flying off, allowing time for the thrips to
be picked off with a moist fine brush, whereas in warmer conditions collection has to be done
more rapidly as the thrips are likely to fly off much more quickly. The thrips are easily seen on
the tray using just a hand lens, but an experienced observer can also see them easily with the
naked eye.
- Plant parts may be sealed in a plastic bag for 24 hours, with a piece of filter paper enclosed to
absorb condensation. Most thrips will leave the plant parts and can then be collected from the
inside of the bag.
- A Berlese funnel can be used to process plant material such as bulbs, flowers, turf, leaf litter,
moss and even dead branches of trees. The funnel contains a sieve on which the plant material is
deposited. Beneath the sieve, the bottom of the funnel leads into a receptacle containing 70–
96% ethanol. An alternative is to use 10% ethanol plus wetting agent as some workers find that
this makes the preparation of good quality microscope slide mounts easier. The funnel is placed
under an electric lamp (60 W), and the heat and light will drive most of the thrips present in the
plants down towards the receptacle. After an appropriate period (e.g. 8 hours for cut flowers),
the content of the receptacle can then be checked under a stereomicroscope.
- Thrips may be monitored (winged adults only) using coloured sticky traps or other appropriate
methods. The ability of a colour to attract thrips varies for different thrips species, but blue or
white traps are good for T. palmi, though yellow traps will also work. For microscope slide
preparation and identification, the thrips will have to be removed from the traps using glueremoving
fluids such as those based on citrus oils, dichloromethane or a turpentine substitute.
There are no recognized methods for extracting thrips pupae from the soil in a quarantine context.
4. Identification
Identification of thrips species by morphological examination is restricted to adult specimens because
there are no adequate keys for the identification of eggs, larvae or pupae. However, the presence of
larvae in samples can give important additional information such as confirming their development on
the host plants. The primary method of identification of adult material is from morphological characters. In order to achieve species identification, these must be examined using a high-power
microscope (e.g. x400). Using this protocol with good-quality slide preparations should allow adult T.
palmi to be identified with certainty by morphological examination alone.
Molecular assays can be applied to all life stages including the immature stages for which
morphological identification to species is not possible. Additionally, in cases where adult specimens
are atypical or damaged, molecular assays may provide further relevant information about their
identity. However specificity of molecular assays is limited as they have been developed for specific
purposes and evaluated against a restricted number of species, using samples from different
geographic regions; therefore, such information needs to be carefully interpreted.
4.1 Morphological identification of the adult thrips
4.1.1 Preparation of thrips for microscopic examination
For high-power microscopic examination, adult thrips must be mounted on microscope slides.
Specimens to be kept in a reference collection are best macerated, dehydrated and mounted in Canada
balsam; Mound and Kibby (1998) provide a full description of this process. However, the full slide
preparation protocol for archival mounts takes 3 days to complete.
For routine identifications, a water-soluble mountant such as Hoyer’s medium (50 ml water, 30 g gum
arabic, 200 g chloral hydrate, 20 ml glycerine) is more rapid and relatively inexpensive. One popular
method of routine slide preparation is given by Mound and Kibby (1998) and described below
(different laboratories may find that other variants work equally well):
Transfer the specimens from the collecting fluid into clean 70% ethanol; if the specimens are
reasonably flexible, attempt to spread the legs, wings and antennae using micropins; transfer a single
thrips, ventral side uppermost, to a drop of Hoyer’s medium on a 13 mm diameter cover slip and use
micropins to rearrange the thrips if necessary; gently lower a microscope slide onto the mountant so
that the cover slip and mountant adhere to the middle of the slide; invert the slide as soon as the
mountant has spread to the edges of the cover slip; label the slide with details including locality, date
of collection and host plant; place the slide, cover slip up, into a drying oven at 35–40 °C and leave for
6 hours before attempting study; leave in the oven for approximately 3 weeks to dry the mountant,
before sealing the cover slip with resin or nail varnish.
4.1.2 Identification of the family Thripidae
Thrips palmi belongs to the family Thripidae, which includes more than 2000 species in 276 genera.
Species share the characteristics outlined in Table 1.
Table 1: Family Thripidae – shared characteristics
Body part Characteristic
Antennae seven or eight segments (occasionally six or nine)
segments III–IV have emergent sense cones (sensoria)
Forewings (if fully developed) usually slender, with two longitudinal veins each bearing a series of setae
Abdomen – female with a serrated ovipositor, which is turned downwards at the apex
Median sternites – male with or without glandular areas
4.1.3 Identification of the genus Thrips
The genus Thrips contains more than 280 species from all parts of the world, though the genus is
primarily from the Holarctic region and the Old World tropics. Members of the genus share the
characteristics outlined in Table 2.
Table 2: Genus Thrips – shared characteristics, adult specimens
Body part Characteristic
Body form (female) macropterous or micropterous
Antennae seven or eight segments
segments III–IV with forked emergent sense cones
Ocellar setae only two pairs present (pair I absent)
pair II shorter (at least no longer) than pair III
Pronotum two pairs (rarely one or none) of major posteroangular setae
usually three, sometimes four, pairs of posteromarginal setae
Prosternal basantra no setae present
Forewings the first vein with variably spaced setal row, second vein with complete setal
row
clavus with five veinal setae (rarely six)
Metascutum median pair of setae at or behind the anterior margin
striate or reticulate sculpturing
campaniform sensilla (metanotal pores) present or absent
Metasternal furca without a spinula
Fore tibia apical claw absent
Tarsi two-segmented
Abdominal tergites and
sternites
without posteromarginal craspeda (flanges)
Abdominal tergites tergites V–VIII with paired ctenidia laterally (combs – each comprising a
submarginal row of microtrichia) (occasionally also on IV)
tergite VIII: ctenidia posteromesad to the spiracles
Abdominal sternites and
pleurotergites
with or without discal (accessory) setae
Abdominal sternites (male) abdominal sterna III–VII, or less, each with a glandular area
(A simplified summary of the main characteristics is given in Table 4 and is accompanied by
illustrative line drawings and photomicrographs (Figures 4 to 5.12).)
Identification of the adults can be carried out with keys. Mound and Kibby (1998) provided a key to
14 Thrips species of economic importance including T. palmi. In addition, a CD-ROM identification
aid for thrips is available which includes an identification system to 100 pest species from around the
world based on photomicrographs (Moritz et al., 2004).
More comprehensive keys to the genus are available, produced on a regional basis (no such key has
been produced for the Afrotropical region):
Asia: Bhatti (1980) and Palmer (1992) provide keys for the identification of species of Thrips
occurring in the Asian tropics. Mound & Azidah (2009) provide a key to the species of
Peninsular Malaysia.
Europe: zur Strassen (2003) has produced the most recent comprehensive key to the species of Europe
including Thrips (in German).
North, Central and South America: Nakahara (1994) provides a key for Thrips species from the New
World. A key to the species of Thrips found in Central and South America is given by Mound
and Marullo (1996) though only one of these species is native to the region.
Oceania: Mound and Masumoto (2005) provide a key to the Thrips species of Oceania. (The authors
of the paper are aware of the error inadvertently introduced on p. 42 in the section
“Relationships” whereby a characteristic of T. flavus Schrank – ocellar setae III close together
behind the first ocellus – is attributed to T. palmi. The correct information is provided in the T.
palmi species description immediately above and is illustrated in Figure 72.)
4.1.4 Identification of Thrips palmi
4.1.4.1 Morphological characteristics of Thrips palmi
Bhatti (1980), Bournier (1983), Sakimura et al. (1986), zur Strassen (1989), Nakahara (1994) and
Mound and Masumoto (2005) all provide detailed descriptions of T. palmi. Sakimura et al. (1986)
gave a list of major diagnostic characters to distinguish T. palmi from the other known species of the
genus Thrips; a modified version is presented in Table 3.
Thrips palmi can be reliably separated from all other species of the genus Thrips by the possession of
all the characters listed in Table 3. Nevertheless, thrips morphology is subject to variation even within
a single species and some characters listed here may be subject to occasional slight variation. For
instance antennal coloration or the number of distal setae on the forewing can vary from the most
commonly observed states. If the specimen differs with respect to one or more of these character
states, then the identification should be checked by reference to an appropriate regional key such as
those listed in section 4.1.3.
Table 3: A list of morphological characteristics that collectively distinguish Thrips palmi from other species in the
genus Thrips
Morphological character
1. A clear yellow body with no dark areas on the head, thorax or abdomen (slightly thickened blackish
body setae); antennal segments I and II pale, III yellow with apex shaded, IV to VII brown but usually
with base of IV–V yellow; forewings uniformly slightly shaded, prominent setae dark
2. Antennae always seven-segmented
3. Postocular setae II and IV much smaller than remaining setae
4. Ocellar setae III standing either just outside of the ocellar triangle, or touching the tangent lines
connecting the anterior ocellus and each of the posterior ocelli
5. Metascutum with sculpture converging posteriorly; median pair of setae behind anterior margin; paired
campaniform sensilla present
6. Forewing first vein with three (occasionally two) distal setae
7. Abdominal tergite II with four lateral marginal setae
8. Abdominal tergites III to IV with setae S2 dark and subequal to S3
9. Abdominal tergite VIII with posteromarginal comb in female complete, in male broadly developed
posteriorly
10. Abdominal tergite IX usually with two pairs of campaniform sensilla (pores)
11. Abdominal sternites without discal setae or ciliate microtrichia
12. Abdominal pleurotergites without discal setae
13. Male: sternites III–VII each with a narrow transverse glandular area
A simplified summary of the main characteristics is given in Table 4 and is accompanied by
illustrative line drawings and photomicrographs (Figures 4 to 5.12).
4.1.4.2 Comparison with similar species (species that are yellow without darker body
markings, or predominantly yellow, or sometimes yellow)
For each species listed here, the main character differences by which they may be separated from
Thrips palmi are given. If in any doubt, refer to an appropriate regional key such as those listed in
section 4.1.3. These also give details of other Thrips species that are not listed below.
Two Indian species (T. alatus Bhatti and T. pallidulus Bagnall) are very similar to T. palmi, although
little is known about their biology.
Thrips alatus
- antennal segment V uniformly brown
- abdominal tergites III and IV with setae S2 paler and much weaker than S3 in both sexes
- the striate sculpture on the metascutum usually not converging posteriorly
- distribution: India, Malaysia, Nepal.
Thrips pallidulus
- antennal segment IV pale
- sculpture on the metascutum medially reticulate, not striate
- distribution: India.
Three common Palearctic species (but also with wider distributions) that may be confused with
T. palmi are T. flavus, T. nigropilosus Uzel and T. tabaci Lindeman.
Thrips flavus
- ocellar setae pair III inside the ocellar triangle, just behind the anterior ocellus
- length of antennal segment VI, 54–60 μm (42–48 μm in T. palmi)
- lines of sculpture on the metascutum not converging posteriorly
- distribution: common flower thrips throughout Asia, Europe.
Thrips nigropilosus
- usually with dark markings on the thorax and abdomen
- metascutum with irregular reticulations medially (longitudinal striae in T. palmi) and no
campaniform sensilla
- abdominal tergite II with three lateral marginal setae
- abdominal tergites IV–V with median pair of setae (S1) more than 0.5 times as long as the
median length of their tergites (less than 0.3 times in T. palmi)
- distribution: common leaf-feeding species, sometimes a pest of plants in the family Compositae;
Asia, East Africa, Europe, North America, Oceania.
Thrips tabaci
- highly variable in coloration, but usually with more or less brown or greyish markings
- all postocular setae subequal in length
- metascutum with irregular longitudinal reticulations, usually with small internal wrinkles
medially, and no campaniform sensilla
- forewing first vein usually with four (occasionally between two or six) distal setae
- abdominal tergite II with three lateral marginal setae
- abdominal tergite IX with posterior pair of campaniform sensilla only
- abdominal pleurotergites with numerous ciliate microtrichia arising from lines of sculpture
- male: narrow transverse glandular area on abdominal sternites III–V only
- distribution: polyphagous pest with a worldwide distribution.
Two further species, one Palearctic (T. alni Uzel) and one European (T. urticae Fabricius), are less
commonly encountered but may be confused with T. palmi. Females of T. alni are particularly similar
in morphology to those of T. palmi.
Thrips alni
- antennal segment V uniformly brown
- abdominal tergites II–V with setae S2 pale
- abdominal tergite V with seta S2 much weaker than seta S3 (these setae are subequal in
T. palmi)
- abdominal tergite VIII with seta S1 subequal to seta S2 (S1 is much weaker than S2 in T. palmi)
- male: abdominal sternites III–VI each with a small oval glandular area
- distribution: restricted to the leaves of Alnus, Betula, Salix; Europe, Siberia, Mongolia.
Thrips urticae
- pronotum with a pair of setae on the anterior margin almost twice as long as any of the discal
setae (usually more than 30 μm; not so in T. palmi, all less than 25 μm)
- metascutum with longitudinal reticulations medially
- abdominal tergites usually with a grey area medially
- abdominal tergite IX with posterior pair of campaniform sensilla only
- distribution: restricted to Urtica dioica; Europe.
Table 4: Simplified checklists of the diagnostic features for quick recognition: (a) the genus Thrips; (b) Thrips
palmi (See Figure 4 for the location of the various features.)
(a) Specimens can be recognized as Thrips by the following combination of characters
Antenna with seven or eight distinct segments; segments III and IV with
forked sense cones
Figs 5.1,
5.2
Head with two pairs of ocellar setae (II and III); pair I missing, pair II
shorter than pair III
Fig. 5.3
Forewing 1st vein – setal row on the first vein continuous or interrupted Fig. 5.5
Abdominal tergites V to VIII with paired ctenidia Fig. 5.6
Abdominal tergite VIII with ctenidia posteromesad to the spiracles Fig. 5.6
(b) Specimens can be identified as Thrips palmi by the presence of the following characters
Body colour clear yellow body with no dark areas on the head, thorax or
abdomen; antennal segments I and II are pale
Figs 1–3
Antennal segment V usually yellowish in basal ⅓ to ½ Fig. 5.1
Antennal segment VI length = 42–48 μm Fig. 5.1
Head: ocellar setae pair III with their bases sited outside of the ocellar triangle or touching
the tangent lines connecting the anterior ocellus to each of the
posterior ocelli
Fig. 5.3
Pronotum with two pairs of major posteroangular setae Fig. 5.4
Forewing: 1st vein with three (occasionally two) distal setae Fig. 5.5
Metascutum with median pair of setae behind the anterior margin and a pair of
campaniform sensilla; with striate sculpture converging
posteriorly
Fig. 5.7
Abdominal pleurotergites discal setae absent; lines of sculpture without ciliate microtrichia Fig. 5.8
Abdominal tergite II with four lateral marginal setae Fig. 5.9
Abdominal tergites III and IV S2 almost equal to S3 Fig. 5.10
Table 4 continued
Abdominal tergite VIII female with complete posteromarginal comb; male with
posteromarginal comb broadly developed medially
Fig. 5.6
Abdominal tergite IX with anterior and posterior pairs of campaniform sensilla (pores) Fig. 5.11
Male: sternites transverse glandular areas on sternites III to VII Fig. 5.12
4.2 Molecular assays for identifying Thrips palmi
Four molecular assays have been published that can be used to support a morphological identification
of T. palmi and these are described below. The specificity of each assay is also described. This
indicates the thrips species against which each assay was evaluated and the original use for which the
assay was designed. A CD-ROM identification system is also available that includes molecular data
for thrips species (Moritz et al., 2004). Considering the specific limitations of molecular methods a
negative molecular test result does not exclude the possibility of positive identification by
morphological methods.
In this diagnostic protocol, methods (including reference to brand names) are described as published,
as these define the original level of sensitivity, specificity and/or reproducibility achieved.
Requirements for controls
With all molecular methods the use of appropriate controls is essential; a validated T. palmi-positive
extract must be included as an additional sample to ensure that amplification has been successful. PCR
amplification, either for real-time PCR or PCR-RFLP, must also be performed on a sample with no
DNA. This negative control indicates possible reagent contamination and false positives.
DNA extraction
DNA may be extracted from single eggs, adults, pupae or larvae. For each of the assays described
below refer to the source paper for the original specific DNA extraction technique used. Laboratories
may find that alternative extraction techniques work equally well; DNA may be extracted using any
DNA extraction methods suitable for insects. For example:
- The thrips may be ground in a lysis buffer in a microtube using a micropestle, and the
homogenate taken through a proteinase-K-based DNA extraction kit according to the
appropriate manufacturer’s instructions.
- Alternatively, a thrips may be ground in 50 μl nuclease-free water before the addition of 50 μl
of a 1:1 (volume to volume) slurry of Chelex 100 resin, and nuclease-free water, heated to 95 ºC
for 5 min and centrifuged at 11,000 g for 5 min. The supernatant is transferred to a new
microtube and stored at −20 ºC.
Several recent papers have described non-destructive techniques for extracting DNA from thrips,
which have the advantage that after DNA extraction has been completed a cleared specimen remains
available for slide mounting (e.g., Rugman-Jones et al., 2006; Mound and Morris, 2007).
4.2.1 SCAR marker-generated sequence-based real-time PCR assay for Thrips palmi
This assay of Walsh et al. (2005) was designed as a species-specific assay against T. palmi for use by
the phytosanitary authorities in England and Wales. It was evaluated by screening it against 21 other
species of Thysanoptera, including ten belonging to the genus Thrips (T. flavus, T. major Uzel, T.
minutissimus L., T. nigropilosus, T. sambuci Heeger, T. tabaci, T. trehernei Priesner or T. physapus L.,
T. urticae, T. validus Uzel, T. vulgatissimus Haliday). These were predominantly, but not exclusively,
European species.
Methodology
The T. palmi-specific PCR primers and TaqMan probe used in this assay were as follows:
PCR primer: P4E8-362F (5′-CCGACAAAATCGGTCTCATGA-3′)
PCR primer: P4E8-439R (5′-GAAAAGTCTCAGGTACAACCCAGTTC-3′)
TaqMan probe: P4E8-385T (FAM 5′-AGACGGATTGACTTAGACGGGAACGGTT-3′ TAMRA).
Real-time PCR reactions were set up using the TaqMan PCR core reagent kit (Applied Biosystems)1,
with 1 μl (10–20 ng) of DNA extract, 7.5 pmol of each primer and 2.5 pmol probe in a total volume of
25 μl. Plates were cycled at generic system conditions (10 min at 95 °C and 40 cycles of 1 min at
60 °C, 15 s at 95 °C) on either of the ABI Prism 7700 or ABI 7900HT Sequence Detection Systems
(Applied Biosystems)2, using real-time data collection. Ct values lower than 40 indicated the presence
of T. palmi DNA.
4.2.2 COI sequence-based real-time PCR assay for Thrips palmi
This assay of Kox et al. (2005) was designed as a species-specific assay against T. palmi for use by the
phytosanitary authorities in the Netherlands. It was evaluated by screening the assay against 23 other
species of thrips, including 11 belonging to the genus Thrips (T. alliorum (Priesner), T. alni, T.
angusticeps Uzel, T. fuscipennis Haliday, T. latiareus Vierbergen, T. major, T. minutissimus, T.
parvispinus (Karny), T. tabaci, T. urticae, T. vulgatissimus). These were predominantly, but not
exclusively, European species.
Methodology
The Thrips palmi-specific PCR primers and TaqMan probe used in this assay are as follows:
PCR primer: Tpalmi 139F* (5′-TCA TGC TGG AAT TTC AGT AGA TTT AAC-3′)
PCR primer: Tpalmi 286R* (5′-TCA CAC RAA TAA TCT TAG TTT TTC TCT TG-3′)
TaqMan probe: TpP (6-FAM 5′-TAG CTG GGG TAT CCT CAA-3′ MGB).
* Primers have been adjusted for greater sensitivity since original publication.
(COI sequences that mismatch with the TaqMan probe in this assay have been deposited on GenBank
from a number of specimens from India identified as T. palmi on the basis of their morphology
(Asokan et al., 2007). These sequences would not produce a positive result using this assay. The
taxonomic or phylogenetic significance of this sequence differentiation currently remains unclear.)
The 25 μl reaction mixture contained 12.5 μl of 2x TaqMan Universal Master Mix (Applied
Biosystems)3, 0.9 μM each primer, 0.1 μM TaqMan probe, 1.0 μl DNA. The real-time PCR was
performed on either of the ABI Prism 7700 or ABI 7900HT Sequence Detection Systems (Applied
Biosystems)4 using the following conditions: 10 min at 95 °C; then 40 cycles of 1 min at 60 °C and 15
s at 94 °C. Ct values lower than 40 indicated the presence of T. palmi DNA.
4.2.3 ITS2 sequence-based PCR-RFLP assay for nine species of thrips including Thrips
palmi
This assay (Toda and Komazaki, 2002) was designed to separate nine species of thrips, including T.
palmi, that are found in fruit trees in Japan: Frankliniella occidentalis (Pergande), F. intonsa
(Trybom), T. hawaiiensis Morgan, T. coloratus Schmutz, T. flavus, T. tabaci, T. palmi, T. setosus
Moulton, Scirtothrips dorsalis Hood.
1, 2 The use of the brand Applied Biosystems for the TaqMan PCR core reagent kit and the ABI Prism 7700 or
ABI 7900HT Sequence Detection Systems in this diagnostic protocol implies no approval of them to the
exclusion of others that may also be suitable. This information is given for the convenience of users of this
protocol and does not constitute an endorsement by the CPM of the chemical, reagent and/or equipment named.
Equivalent products may be used if they can be shown to lead to the same results.
3, 4 The use the brand Applied Biosystems for the TaqMan Universal Master Mix and ABI Prism 7700 or ABI
7900HT Sequence Detection Systems in this diagnostic protocol implies no approval of them to the exclusion of
others that may also be suitable. This information is given for the convenience of users of this protocol and does
not constitute and endorsement by the CPM of the chemical, reagent and/or equipment named. Equivalent
products may be used if they can be shown to lead to the same results.
Methodology
The PCR primers (located in the 5.8 S and 28 S regions flanking the ITS2 region of ribosomal DNA)
used in this assay were as follows:
5′-TGTGAACTGCAGGACACATGA-3′
5′-GGTAATCTCACCTGAACTGAGGTC-3′.
T. palmi generated a 588-base-pair (bp) PCR product (longer or shorter fragments were produced from
the other species). The 20 μl reaction mixture was composed as follows: 1 μM each primer, 250 μM
dNTPs, 1 Unit of AmpliTaq Gold DNA polymerase (Applied Biosystems)5, 2 μl 10x reaction buffer
[with 25 mM MgCl2], 0.5 μl DNA. The PCR was performed in a 9600 DNA thermocycler (Applied
Biosytems)6, with the following conditions: 9 min at 95 °C, 35 cycles of 1 min at 94 °C, 30 s at 50 °C,
and 1 min at 72 °C, followed by a final extension for 7 min at 72 °C and quickly cooled to room
temperature. The PCR products were analysed by agarose gel electrophoresis.
5 μl of PCR product (without purification) was digested with the enzyme RsaI according to the
manufacturer’s instructions. Digested PCR products were separated by 2.0% agarose gel
electrophoresis.
Restriction fragment sizes produced by T. palmi when the ITS2 fragment is digested with RsaI were as
follows: 371, 98, 61 and 58 bp.
4.2.4 COI sequence-based PCR-RFLP assay for ten species of thrips including Thrips
palmi
This assay of Brunner et al. (2002) was designed to separate ten species of thrips, including T. palmi,
which are mostly, but not exclusively, pest species found in Europe: Anaphothrips obscurus (Müller),
Echinothrips americanus Morgan, Frankliniella occidentalis, Heliothrips haemorrhoidalis (Bouché),
Hercinothrips femoralis (Reuter), Parthenothrips dracaenae (Heeger), Taeniothrips picipes
(Zetterstedt), Thrips angusticeps Uzel, T. palmi, T. tabaci.
Methodology
The PCR primers (located in the mitochondrial COI gene sequence) used in this assay are as follows:
mtD-7.2F (5′-ATTAGGAGCHCCHGAYATAGCATT-3′)
mtD9.2R (5′-CAGGCAAGATTAAAATATAAACTTCTG-3′).
These primers amplified a 433-bp fragment in all the species separated by this assay. The 50 μl
reaction mixture was composed as follows: 0.76 μM each primer, 200 μM dNTPs, 1 Unit Taq DNA
polymerase, 5 μl 10X reaction buffer [with 15 mM MgCl2], 1 μl DNA. The PCR was performed in a
standard thermocycler with the following conditions: 1 min 94 °C, 40 cycles of 15 s at 94 °C, 30 s at
55 °C, and 45 s at 72 °C, followed by a final extension for 10 min at 72 °C and quickly cooled to room
temperature. To gauge the fragment size produced after amplification, 5 μl of the PCR products were
analysed by 1.0–2.0% agarose gel electrophoresis.
5 μl of PCR product (without purification) was digested with the enzymes AluI and Sau3AI in separate
reactions according to the manufacturer’s instructions. Digested PCR products were separated by
agarose gel electrophoresis.
5, 6 The use of the brand Applied Biosystems AmpliTaq Gold DNA polymerase and 9600 DNA thermocycler in
this diagnostic protocol implies no approval of them to the exclusion of others that may be suitable. This
information is given for the convenience of users of this protocol and does not constitute and endorsement by the
CPM of the chemical, reagent and/or equipment named. Equivalent products may be used if they can be shown
to lead to the same results.
Restriction fragment sizes produced by T. palmi when the COI fragment is digested with AluI and
Sau3AI are as follows:
AluI: 291 and 194 bp
Sau3AI: 293, 104, 70 and 18 bp.
5. Records
Records and evidence should be retained as described in section 2.5 of ISPM 27:2006.
In cases where other contracting parties may be adversely affected by the diagnosis, the records and
evidence (in particular, preserved or slide-mounted specimens, photographs of distinctive taxonomic
structures, DNA extracts and photographs of gels, as appropriate), should be kept for at least one year.
6. Contact points for further information
Entomology Section, National Reference Laboratory, Plant Protection Service, P.O. Box 9102, 6700
HC Wageningen, Netherlands. Telephone: +31 317 496824; e-mail: g.vierbergen@minlnv.nl;
fax: +31 317 423977.
Pest and Disease Identification Team, The Food and Environment Research Agency, Sand Hutton,
York YO41 1LZ, United Kingdom. Telephone: +44 1904 462215; e-mail:
dom.collins@fera.gsi.gov.uk; fax: +44 1904 462111.
Area EntomologÃa, Departamento Laboratorios Biológicos, Dirección General de Servicios AgrÃcolas,
MGAP, Av. Millán 4703, C. P. 12900, Montevideo, Uruguay. Telephone: +598 2304 3992; email:
ifrioni@mgap.gub.uy; fax: +598 2304 3992.
7. Acknowledgements
The first draft of this protocol was written by D.W. Collins, Pest and Disease Identification
Programme, The Food and Environment Research Agency, Sand Hutton, York, YO41 1LZ, United
Kingdom; G. Vierbergen, Dr. L.F.F. Kox, Plant Protection Service, Section of Entomology,
Wageningen, Netherlands; and Ing. Agr. N.C. Vaccaro, Sección EntomologÃa, INTA-EEA Concordia,
Argentina. Line drawings for Figure 5 were produced by S. Kobro, Norwegian Crop Protection
Institute, Norway.
8. References
Asokan, R., Krishna Kumar, N.K., Kumar, V. & Ranganath, H.R. 2007. Molecular differences in
the mitochondrial cytochrome oxidase I (mtCOI) gene and development of a species-specific
marker for onion thrips, Thrips tabaci Lindeman, and melon thrips, T. palmi Karny
(Thysanoptera: Thripidae), vectors of tospoviruses (Bunyaviridae). Bulletin of Entomological
Research, 97: 461–470.
Bhatti, J.S. 1980. Species of the genus Thrips from India (Thysanoptera). Systematic Entomology, 5:
109–166.
Bournier, J.P. 1983. Un insecte polyphage: Thrips palmi (Karny), important ravageur du cotonnier
aux Philippines. Cotonnier et Fibres Tropicales, 38: 286–288.
Brunner, P.C., Fleming, C. & Frey, J.E. 2002. A molecular identification key for economically
important thrips species (Thysanoptera: Thripidae) using direct sequencing and a PCR-RFLPbased
approach. Agricultural and Forest Entomology, 4: 127–136.
EPPO. 2008. URL: http://www.eppo.org/. Accessed 17 June 2008.
EPPO/CABI. 1997. Thrips palmi. In I.M. Smith, D.G. McNamara, P.R. Scott & M. Holderness, eds.
Quarantine pests for Europe, 2nd edition. Wallingford, UK, CAB International. 1425 pp.
Kox, L.F.F., van den Beld, H.E., Zijlstra, C. & Vierbergen, G. 2005. Real-time PCR assay for the
identification of Thrips palmi. Bulletin OEPP/EPPO Bulletin, 35: 141–148.
Mantel, W.P. & Vierbergen, G. 1996. Additional species to the Dutch list of Thysanoptera and new
intercepted Thysanoptera on imported plant material. Folia Entomologica Hungarica, 57
(Suppl.): 91–96.
Moritz, G., Mound, L.A., Morris, D.C. & Goldarazena, A. 2004. Pest thrips of the world: visual
and molecular identification of pest thrips (CD-ROM), Centre for Biological Information
Technology (CBIT), University of Brisbane. ISBN 1-86499-781-8.
Mound, L.A. & Azidah, A.A. 2009. Species of the genus Thrips (Thysanoptera) from Peninsular
Malaysia, with a checklist of recorded Thripidae. Zootaxa, 2023: 55–68.
Mound, L.A. & Kibby, G. 1998. Thysanoptera. An Identification Guide. 2nd edition. Wallingford,
UK, CAB International. 70 pp.
Mound, L.A. & Marullo, R. 1996. The thrips of Central and South America: an introduction (Insecta:
Thysanoptera). Memoirs on Entomology, International, 6: 1–488.
Mound, L.A. & Masumoto, M. 2005. The genus Thrips (Thysanoptera, Thripidae) in Australia, New
Caledonia and New Zealand. Zootaxa, 1020: 1–64.
Mound, L.A. & Morris, D.C. 2007. A new thrips pest of Myoporum cultivars in California, in a new
genus of leaf-galling Australian Phlaeothripidae (Thysanoptera). Zootaxa, 1495: 3545.
Murai, T. 2002. The pest and vector from the East: Thrips palmi. In R. Marullo, & L.A. Mound, eds.
Thrips and Tospoviruses: Proceedings of the 7th International Symposium on Thysanoptera.
Italy, 2–7 July 2001, pp. 19–32. Canberra, Australian National Insect Collection.
Nakahara, S. 1994. The genus Thrips Linnaeus (Thysanoptera: Thripidae) of the New World. USDA
Technical Bulletin No. 1822. 183 pp.
PaDIL. 2007. Pests and Diseases Image Library. URL: http://www.padil.gov.au. Accessed 18 Oct
2007.
Palmer, J.M. 1992. Thrips (Thysanoptera) from Pakistan to the Pacific: a review. Bulletin of the
British Museum (Natural History). Entomology Series, 61: 1–76.
Rugman-Jones, P.F., Hoddle, M.S., Mound, L.A. & Stouthamer, R. 2006. Molecular identification
key for pest species of Scirtothrips (Thysanoptera: Thripidae). Journal of Economic
Entomology, 99 (5): 1813–1819.
Sakimura, K., Nakahara, L.M. & Denmark, H.A. 1986. A thrips, Thrips palmi Karny
(Thysanoptera: Thripidae). Entomology Circular No. 280. Division of Plant Industry, Florida;
Dept. of Agriculture and Consumer Services. 4 pp.
Toda, S. & Komazaki, S. 2002. Identification of thrips species (Thysanoptera: Thripidae) on
Japanese fruit trees by polymerase chain reaction and restriction fragment length polymorphism
of the ribosomal ITS2 region. Bulletin of Entomological Research, 92: 359–363.
Walsh, K., Boonham, N., Barker, I. & Collins, D.W. 2005. Development of a sequence-specific
real-time PCR to the melon thrips Thrips palmi (Thysan., Thripidae). Journal of Applied
Entomology, 129 (5): 272–279.
zur Strassen, R. 1989. Was ist Thrips palmi? Ein neuer Quarantäne-Schädling in Europa. Gesunde
Pflanzen, 41: 63–67.
zur Strassen, R. 2003. Die terebranten Thysanopteren Europas und des Mittelmeer-Gebietes. In Die
Tierwelt Deutschlands. Begründet 1925 von Friedrich Dahl, 74: 5–277. Keltern, Goecke &
Evers.
Publication history
2006-04 CPM-1 added topic diagnostic protocol for Thrips palmi (2006-038)
2006-10 TPDP developed draft text
2007-05 SC approved draft text for MC
2007-06 Sent for MC under fast-track process
2007-10 SC-7 revised draft text
2007-11 SC requested TPDP to review
2008-11 SC noted draft text under TPDP review
2009-05 SC recalled draft text to TPDP
2009-11 SC approved revised draft for MC
2009-12 Sent for MC under fast-track process
2009-12 SC revised draft text for adoption via e-decision
2010-03 CPM-5 adopted Annex 1 to ISPM 27
ISPM 27. 2006: Annex 1 Thrips palmi Karny (2010)
Publication history: Last modified August 2011
The annex is a prescriptive part of ISPM 27:2006.
INTERNATIONAL STANDARDS FOR PHYTOSANITARY MEASURES
ISPM 27
Annex 1
ISPM 27 DIAGNOSTIC PROTOCOLS
DP 1:
Thrips palmi Karny
(2010)
CONTENTS
1. Pest Information ..................................................................................................................... DP 1-2
2. Taxonomic Information .......................................................................................................... DP 1-3
3. Detection ................................................................................................................................. DP 1-3
4. Identification ........................................................................................................................... DP 1-4
4.1 Morphological identification of the adult thrips ...................................................... DP 1-5
4.1.1 Preparation of thrips for microscopic examination ................................................. DP 1-5
4.1.2 Identification of the family Thripidae ..................................................................... DP 1-5
4.1.3 Identification of the genus Thrips ........................................................................... DP 1-5
4.1.4 Identification of Thrips palmi ................................................................................. DP 1-7
4.1.4.1 Morphological characteristics of Thrips palmi ....................................................... DP 1-7
4.1.4.2 Comparison with similar species (species that are yellow without darker body
markings, or predominantly yellow, or sometimes yellow) .................................... DP 1-8
4.2 Molecular assays for identifying Thrips palmi ...................................................... DP 1-16
4.2.1 SCAR marker-generated sequence-based real-time PCR assay for Thrips palmi . DP 1-16
4.2.2 COI sequence-based real-time PCR assay for Thrips palmi ................................. DP 1-17
4.2.3 ITS2 sequence-based PCR-RFLP assay for nine species of thrips including Thrips
palmi ...................................................................................................................... DP 1-17
4.2.4 COI sequence-based PCR-RFLP assay for ten species of thrips including Thrips
palmi ...................................................................................................................... DP 1-18
5. Records ................................................................................................................................. DP 1-19
6. Contact points for further information .................................................................................. DP 1-19
7. Acknowledgements .............................................................................................................. DP 1-19
8. References ............................................................................................................................ DP 1-19
1. Pest Information
Thrips palmi Karny (Thysanoptera: Thripidae) is a polyphagous plant pest, especially of species in the
Cucurbitaceae and Solanaceae. It appears to have originated in Southern Asia and to have spread from
there during the latter part of the twentieth century. It has been recorded throughout Asia and is
widespread throughout the Pacific and the Caribbean. It has been recorded locally in North, Central
and South America and Africa. For more general information about T. palmi, see EPPO/CABI (1997)
or Murai (2002); online pest data sheets are also available from the Pests and Diseases Image Library
(PaDIL, 2007) and EPPO (EPPO, 2008).
The species causes economic damage to plant crops both as a direct result of its feeding activity and
from its ability to vector tospoviruses such as Groundnut bud necrosis virus, Melon yellow spot virus
and Watermelon silver mottle virus. It is extremely polyphagous, and has been recorded from more
than 36 plant families. It is an outdoor pest of, amongst others, Benincasa hispida, Capsicum annuum,
Citrullus lanatus, Cucumis melo, Cucumis sativus, Cucurbita spp., Glycine max, Gossypium spp.,
Helianthus annuus, Nicotiana tabacum, Phaseolus vulgaris, Pisum sativum, Sesamum indicum,
Solanum melongena, Solanum tuberosum and Vigna unguiculata. In glasshouses, economically
important hosts are Capsicum annuum, Chrysanthemum spp., Cucumis sativus, Cyclamen spp., Ficus
spp., Orchidaceae and Solanum melongena. The thrips may be carried on plants for planting, cut
flowers and fruits of host species, as well as on or associated with packing material, and in soil.
Thrips palmi is almost entirely yellow in coloration (Figures 1–3), and its identification is hampered
by both its small size (1.0–1.3 mm) and its great similarity to certain other yellow or predominantly
yellow species of Thrips.
Figure 1: Thrips palmi, female (left) and male (photo: A. J. M. Loomans, PPS, Wageningen, the Netherlands;
scale bar = 500 μm = 0.5 mm)
Figure 2: Thrips palmi, female
Figure 3: Thrips palmi, male
(Photos: W. Zijlstra, PPS, Wageningen, the Netherlands; scale bars: 300 μm)
2. Taxonomic Information
Name: Thrips palmi Karny, 1925
Synonyms: Thrips clarus Moulton, 1928
Thrips leucadophilus Priesner, 1936
Thrips gossypicola Ramakrishna & Margabandhu, 1939
Chloethrips aureus Ananthakrishnan & Jagadish, 1967
Thrips gracilis Ananthakrishnan & Jagadish, 1968
Taxonomic position: Insecta, Thysanoptera, Terebrantia, Thripidae
Common name: melon thrips
3. Detection
Thrips palmi may be found in different locations depending on the life stages present.
eggs in the leaf, flower and fruit tissue
larva I on the leaves, flowers and fruits
larva II on the leaves, flowers and fruits
pupa I in the soil, packing cases and growing medium
pupa II in the soil, packing cases and growing medium
adult on the leaves, flowers and fruits
On plant material, T. palmi may potentially be found on most above-ground parts of the plant; the
parts of the plant infested can differ according to variables such as the host and the characteristics of
each separate T. palmi population.
During visual examination of plant material for the presence of T. palmi, attention must be paid to
silvery feeding scars on the leaf surfaces of host plants, especially alongside the midrib and the veins.
Heavily infested plants are often characterized by a silvered or bronzed appearance of the leaves,
stunted leaves and terminals, or scarred and deformed fruits. Detection may be hampered in
circumstances such as:
- low-level infestation, which may produce little or no detectable symptoms
- the presence of the eggs within the plant tissue only (for example after external treatment which
may have removed visible life stages).
Specimens for morphological examination are best collected in a fluid called AGA, which is a mixture
of 10 parts of 60% ethanol with 1 part of glycerine and 1 part of acetic acid. If the specimens are to be
stored, they should be transferred to 60% ethanol and kept in the dark, preferably in a freezer to
prevent loss of colour. However, several laboratories have reported that AGA may act to denature the
DNA of the thrips thereby hindering any subsequent molecular work. An alternative is to use 80–95%
ethanol as the collecting fluid as any unmounted specimens may then be used for molecular studies.
However, in this case specimens must be stored in the freezer until used, or they may prove difficult to
slide mount.
Several methods can be used to collect thrips specimens (Mantel and Vierbergen, 1996; modified):
- Thrips may be individually removed from the plant (leaves, flowers or fruit), and transferred
into microtubes containing AGA, using a moist, fine brush.
- Thrips may be beaten from plant parts onto a small plastic tray (e.g. a white tray for darkcoloured
specimens or a black tray for light-coloured specimens). In cooler conditions, the
thrips usually start walking across the tray rather than flying off, allowing time for the thrips to
be picked off with a moist fine brush, whereas in warmer conditions collection has to be done
more rapidly as the thrips are likely to fly off much more quickly. The thrips are easily seen on
the tray using just a hand lens, but an experienced observer can also see them easily with the
naked eye.
- Plant parts may be sealed in a plastic bag for 24 hours, with a piece of filter paper enclosed to
absorb condensation. Most thrips will leave the plant parts and can then be collected from the
inside of the bag.
- A Berlese funnel can be used to process plant material such as bulbs, flowers, turf, leaf litter,
moss and even dead branches of trees. The funnel contains a sieve on which the plant material is
deposited. Beneath the sieve, the bottom of the funnel leads into a receptacle containing 70–
96% ethanol. An alternative is to use 10% ethanol plus wetting agent as some workers find that
this makes the preparation of good quality microscope slide mounts easier. The funnel is placed
under an electric lamp (60 W), and the heat and light will drive most of the thrips present in the
plants down towards the receptacle. After an appropriate period (e.g. 8 hours for cut flowers),
the content of the receptacle can then be checked under a stereomicroscope.
- Thrips may be monitored (winged adults only) using coloured sticky traps or other appropriate
methods. The ability of a colour to attract thrips varies for different thrips species, but blue or
white traps are good for T. palmi, though yellow traps will also work. For microscope slide
preparation and identification, the thrips will have to be removed from the traps using glueremoving
fluids such as those based on citrus oils, dichloromethane or a turpentine substitute.
There are no recognized methods for extracting thrips pupae from the soil in a quarantine context.
4. Identification
Identification of thrips species by morphological examination is restricted to adult specimens because
there are no adequate keys for the identification of eggs, larvae or pupae. However, the presence of
larvae in samples can give important additional information such as confirming their development on
the host plants. The primary method of identification of adult material is from morphological characters. In order to achieve species identification, these must be examined using a high-power
microscope (e.g. x400). Using this protocol with good-quality slide preparations should allow adult T.
palmi to be identified with certainty by morphological examination alone.
Molecular assays can be applied to all life stages including the immature stages for which
morphological identification to species is not possible. Additionally, in cases where adult specimens
are atypical or damaged, molecular assays may provide further relevant information about their
identity. However specificity of molecular assays is limited as they have been developed for specific
purposes and evaluated against a restricted number of species, using samples from different
geographic regions; therefore, such information needs to be carefully interpreted.
4.1 Morphological identification of the adult thrips
4.1.1 Preparation of thrips for microscopic examination
For high-power microscopic examination, adult thrips must be mounted on microscope slides.
Specimens to be kept in a reference collection are best macerated, dehydrated and mounted in Canada
balsam; Mound and Kibby (1998) provide a full description of this process. However, the full slide
preparation protocol for archival mounts takes 3 days to complete.
For routine identifications, a water-soluble mountant such as Hoyer’s medium (50 ml water, 30 g gum
arabic, 200 g chloral hydrate, 20 ml glycerine) is more rapid and relatively inexpensive. One popular
method of routine slide preparation is given by Mound and Kibby (1998) and described below
(different laboratories may find that other variants work equally well):
Transfer the specimens from the collecting fluid into clean 70% ethanol; if the specimens are
reasonably flexible, attempt to spread the legs, wings and antennae using micropins; transfer a single
thrips, ventral side uppermost, to a drop of Hoyer’s medium on a 13 mm diameter cover slip and use
micropins to rearrange the thrips if necessary; gently lower a microscope slide onto the mountant so
that the cover slip and mountant adhere to the middle of the slide; invert the slide as soon as the
mountant has spread to the edges of the cover slip; label the slide with details including locality, date
of collection and host plant; place the slide, cover slip up, into a drying oven at 35–40 °C and leave for
6 hours before attempting study; leave in the oven for approximately 3 weeks to dry the mountant,
before sealing the cover slip with resin or nail varnish.
4.1.2 Identification of the family Thripidae
Thrips palmi belongs to the family Thripidae, which includes more than 2000 species in 276 genera.
Species share the characteristics outlined in Table 1.
Table 1: Family Thripidae – shared characteristics
Body part Characteristic
Antennae seven or eight segments (occasionally six or nine)
segments III–IV have emergent sense cones (sensoria)
Forewings (if fully developed) usually slender, with two longitudinal veins each bearing a series of setae
Abdomen – female with a serrated ovipositor, which is turned downwards at the apex
Median sternites – male with or without glandular areas
4.1.3 Identification of the genus Thrips
The genus Thrips contains more than 280 species from all parts of the world, though the genus is
primarily from the Holarctic region and the Old World tropics. Members of the genus share the
characteristics outlined in Table 2.
Table 2: Genus Thrips – shared characteristics, adult specimens
Body part Characteristic
Body form (female) macropterous or micropterous
Antennae seven or eight segments
segments III–IV with forked emergent sense cones
Ocellar setae only two pairs present (pair I absent)
pair II shorter (at least no longer) than pair III
Pronotum two pairs (rarely one or none) of major posteroangular setae
usually three, sometimes four, pairs of posteromarginal setae
Prosternal basantra no setae present
Forewings the first vein with variably spaced setal row, second vein with complete setal
row
clavus with five veinal setae (rarely six)
Metascutum median pair of setae at or behind the anterior margin
striate or reticulate sculpturing
campaniform sensilla (metanotal pores) present or absent
Metasternal furca without a spinula
Fore tibia apical claw absent
Tarsi two-segmented
Abdominal tergites and
sternites
without posteromarginal craspeda (flanges)
Abdominal tergites tergites V–VIII with paired ctenidia laterally (combs – each comprising a
submarginal row of microtrichia) (occasionally also on IV)
tergite VIII: ctenidia posteromesad to the spiracles
Abdominal sternites and
pleurotergites
with or without discal (accessory) setae
Abdominal sternites (male) abdominal sterna III–VII, or less, each with a glandular area
(A simplified summary of the main characteristics is given in Table 4 and is accompanied by
illustrative line drawings and photomicrographs (Figures 4 to 5.12).)
Identification of the adults can be carried out with keys. Mound and Kibby (1998) provided a key to
14 Thrips species of economic importance including T. palmi. In addition, a CD-ROM identification
aid for thrips is available which includes an identification system to 100 pest species from around the
world based on photomicrographs (Moritz et al., 2004).
More comprehensive keys to the genus are available, produced on a regional basis (no such key has
been produced for the Afrotropical region):
Asia: Bhatti (1980) and Palmer (1992) provide keys for the identification of species of Thrips
occurring in the Asian tropics. Mound & Azidah (2009) provide a key to the species of
Peninsular Malaysia.
Europe: zur Strassen (2003) has produced the most recent comprehensive key to the species of Europe
including Thrips (in German).
North, Central and South America: Nakahara (1994) provides a key for Thrips species from the New
World. A key to the species of Thrips found in Central and South America is given by Mound
and Marullo (1996) though only one of these species is native to the region.
Oceania: Mound and Masumoto (2005) provide a key to the Thrips species of Oceania. (The authors
of the paper are aware of the error inadvertently introduced on p. 42 in the section
“Relationships” whereby a characteristic of T. flavus Schrank – ocellar setae III close together
behind the first ocellus – is attributed to T. palmi. The correct information is provided in the T.
palmi species description immediately above and is illustrated in Figure 72.)
4.1.4 Identification of Thrips palmi
4.1.4.1 Morphological characteristics of Thrips palmi
Bhatti (1980), Bournier (1983), Sakimura et al. (1986), zur Strassen (1989), Nakahara (1994) and
Mound and Masumoto (2005) all provide detailed descriptions of T. palmi. Sakimura et al. (1986)
gave a list of major diagnostic characters to distinguish T. palmi from the other known species of the
genus Thrips; a modified version is presented in Table 3.
Thrips palmi can be reliably separated from all other species of the genus Thrips by the possession of
all the characters listed in Table 3. Nevertheless, thrips morphology is subject to variation even within
a single species and some characters listed here may be subject to occasional slight variation. For
instance antennal coloration or the number of distal setae on the forewing can vary from the most
commonly observed states. If the specimen differs with respect to one or more of these character
states, then the identification should be checked by reference to an appropriate regional key such as
those listed in section 4.1.3.
Table 3: A list of morphological characteristics that collectively distinguish Thrips palmi from other species in the
genus Thrips
Morphological character
1. A clear yellow body with no dark areas on the head, thorax or abdomen (slightly thickened blackish
body setae); antennal segments I and II pale, III yellow with apex shaded, IV to VII brown but usually
with base of IV–V yellow; forewings uniformly slightly shaded, prominent setae dark
2. Antennae always seven-segmented
3. Postocular setae II and IV much smaller than remaining setae
4. Ocellar setae III standing either just outside of the ocellar triangle, or touching the tangent lines
connecting the anterior ocellus and each of the posterior ocelli
5. Metascutum with sculpture converging posteriorly; median pair of setae behind anterior margin; paired
campaniform sensilla present
6. Forewing first vein with three (occasionally two) distal setae
7. Abdominal tergite II with four lateral marginal setae
8. Abdominal tergites III to IV with setae S2 dark and subequal to S3
9. Abdominal tergite VIII with posteromarginal comb in female complete, in male broadly developed
posteriorly
10. Abdominal tergite IX usually with two pairs of campaniform sensilla (pores)
11. Abdominal sternites without discal setae or ciliate microtrichia
12. Abdominal pleurotergites without discal setae
13. Male: sternites III–VII each with a narrow transverse glandular area
A simplified summary of the main characteristics is given in Table 4 and is accompanied by
illustrative line drawings and photomicrographs (Figures 4 to 5.12).
4.1.4.2 Comparison with similar species (species that are yellow without darker body
markings, or predominantly yellow, or sometimes yellow)
For each species listed here, the main character differences by which they may be separated from
Thrips palmi are given. If in any doubt, refer to an appropriate regional key such as those listed in
section 4.1.3. These also give details of other Thrips species that are not listed below.
Two Indian species (T. alatus Bhatti and T. pallidulus Bagnall) are very similar to T. palmi, although
little is known about their biology.
Thrips alatus
- antennal segment V uniformly brown
- abdominal tergites III and IV with setae S2 paler and much weaker than S3 in both sexes
- the striate sculpture on the metascutum usually not converging posteriorly
- distribution: India, Malaysia, Nepal.
Thrips pallidulus
- antennal segment IV pale
- sculpture on the metascutum medially reticulate, not striate
- distribution: India.
Three common Palearctic species (but also with wider distributions) that may be confused with
T. palmi are T. flavus, T. nigropilosus Uzel and T. tabaci Lindeman.
Thrips flavus
- ocellar setae pair III inside the ocellar triangle, just behind the anterior ocellus
- length of antennal segment VI, 54–60 μm (42–48 μm in T. palmi)
- lines of sculpture on the metascutum not converging posteriorly
- distribution: common flower thrips throughout Asia, Europe.
Thrips nigropilosus
- usually with dark markings on the thorax and abdomen
- metascutum with irregular reticulations medially (longitudinal striae in T. palmi) and no
campaniform sensilla
- abdominal tergite II with three lateral marginal setae
- abdominal tergites IV–V with median pair of setae (S1) more than 0.5 times as long as the
median length of their tergites (less than 0.3 times in T. palmi)
- distribution: common leaf-feeding species, sometimes a pest of plants in the family Compositae;
Asia, East Africa, Europe, North America, Oceania.
Thrips tabaci
- highly variable in coloration, but usually with more or less brown or greyish markings
- all postocular setae subequal in length
- metascutum with irregular longitudinal reticulations, usually with small internal wrinkles
medially, and no campaniform sensilla
- forewing first vein usually with four (occasionally between two or six) distal setae
- abdominal tergite II with three lateral marginal setae
- abdominal tergite IX with posterior pair of campaniform sensilla only
- abdominal pleurotergites with numerous ciliate microtrichia arising from lines of sculpture
- male: narrow transverse glandular area on abdominal sternites III–V only
- distribution: polyphagous pest with a worldwide distribution.
Two further species, one Palearctic (T. alni Uzel) and one European (T. urticae Fabricius), are less
commonly encountered but may be confused with T. palmi. Females of T. alni are particularly similar
in morphology to those of T. palmi.
Thrips alni
- antennal segment V uniformly brown
- abdominal tergites II–V with setae S2 pale
- abdominal tergite V with seta S2 much weaker than seta S3 (these setae are subequal in
T. palmi)
- abdominal tergite VIII with seta S1 subequal to seta S2 (S1 is much weaker than S2 in T. palmi)
- male: abdominal sternites III–VI each with a small oval glandular area
- distribution: restricted to the leaves of Alnus, Betula, Salix; Europe, Siberia, Mongolia.
Thrips urticae
- pronotum with a pair of setae on the anterior margin almost twice as long as any of the discal
setae (usually more than 30 μm; not so in T. palmi, all less than 25 μm)
- metascutum with longitudinal reticulations medially
- abdominal tergites usually with a grey area medially
- abdominal tergite IX with posterior pair of campaniform sensilla only
- distribution: restricted to Urtica dioica; Europe.
Table 4: Simplified checklists of the diagnostic features for quick recognition: (a) the genus Thrips; (b) Thrips
palmi (See Figure 4 for the location of the various features.)
(a) Specimens can be recognized as Thrips by the following combination of characters
Antenna with seven or eight distinct segments; segments III and IV with
forked sense cones
Figs 5.1,
5.2
Head with two pairs of ocellar setae (II and III); pair I missing, pair II
shorter than pair III
Fig. 5.3
Forewing 1st vein – setal row on the first vein continuous or interrupted Fig. 5.5
Abdominal tergites V to VIII with paired ctenidia Fig. 5.6
Abdominal tergite VIII with ctenidia posteromesad to the spiracles Fig. 5.6
(b) Specimens can be identified as Thrips palmi by the presence of the following characters
Body colour clear yellow body with no dark areas on the head, thorax or
abdomen; antennal segments I and II are pale
Figs 1–3
Antennal segment V usually yellowish in basal ⅓ to ½ Fig. 5.1
Antennal segment VI length = 42–48 μm Fig. 5.1
Head: ocellar setae pair III with their bases sited outside of the ocellar triangle or touching
the tangent lines connecting the anterior ocellus to each of the
posterior ocelli
Fig. 5.3
Pronotum with two pairs of major posteroangular setae Fig. 5.4
Forewing: 1st vein with three (occasionally two) distal setae Fig. 5.5
Metascutum with median pair of setae behind the anterior margin and a pair of
campaniform sensilla; with striate sculpture converging
posteriorly
Fig. 5.7
Abdominal pleurotergites discal setae absent; lines of sculpture without ciliate microtrichia Fig. 5.8
Abdominal tergite II with four lateral marginal setae Fig. 5.9
Abdominal tergites III and IV S2 almost equal to S3 Fig. 5.10
Table 4 continued
Abdominal tergite VIII female with complete posteromarginal comb; male with
posteromarginal comb broadly developed medially
Fig. 5.6
Abdominal tergite IX with anterior and posterior pairs of campaniform sensilla (pores) Fig. 5.11
Male: sternites transverse glandular areas on sternites III to VII Fig. 5.12
4.2 Molecular assays for identifying Thrips palmi
Four molecular assays have been published that can be used to support a morphological identification
of T. palmi and these are described below. The specificity of each assay is also described. This
indicates the thrips species against which each assay was evaluated and the original use for which the
assay was designed. A CD-ROM identification system is also available that includes molecular data
for thrips species (Moritz et al., 2004). Considering the specific limitations of molecular methods a
negative molecular test result does not exclude the possibility of positive identification by
morphological methods.
In this diagnostic protocol, methods (including reference to brand names) are described as published,
as these define the original level of sensitivity, specificity and/or reproducibility achieved.
Requirements for controls
With all molecular methods the use of appropriate controls is essential; a validated T. palmi-positive
extract must be included as an additional sample to ensure that amplification has been successful. PCR
amplification, either for real-time PCR or PCR-RFLP, must also be performed on a sample with no
DNA. This negative control indicates possible reagent contamination and false positives.
DNA extraction
DNA may be extracted from single eggs, adults, pupae or larvae. For each of the assays described
below refer to the source paper for the original specific DNA extraction technique used. Laboratories
may find that alternative extraction techniques work equally well; DNA may be extracted using any
DNA extraction methods suitable for insects. For example:
- The thrips may be ground in a lysis buffer in a microtube using a micropestle, and the
homogenate taken through a proteinase-K-based DNA extraction kit according to the
appropriate manufacturer’s instructions.
- Alternatively, a thrips may be ground in 50 μl nuclease-free water before the addition of 50 μl
of a 1:1 (volume to volume) slurry of Chelex 100 resin, and nuclease-free water, heated to 95 ºC
for 5 min and centrifuged at 11,000 g for 5 min. The supernatant is transferred to a new
microtube and stored at −20 ºC.
Several recent papers have described non-destructive techniques for extracting DNA from thrips,
which have the advantage that after DNA extraction has been completed a cleared specimen remains
available for slide mounting (e.g., Rugman-Jones et al., 2006; Mound and Morris, 2007).
4.2.1 SCAR marker-generated sequence-based real-time PCR assay for Thrips palmi
This assay of Walsh et al. (2005) was designed as a species-specific assay against T. palmi for use by
the phytosanitary authorities in England and Wales. It was evaluated by screening it against 21 other
species of Thysanoptera, including ten belonging to the genus Thrips (T. flavus, T. major Uzel, T.
minutissimus L., T. nigropilosus, T. sambuci Heeger, T. tabaci, T. trehernei Priesner or T. physapus L.,
T. urticae, T. validus Uzel, T. vulgatissimus Haliday). These were predominantly, but not exclusively,
European species.
Methodology
The T. palmi-specific PCR primers and TaqMan probe used in this assay were as follows:
PCR primer: P4E8-362F (5′-CCGACAAAATCGGTCTCATGA-3′)
PCR primer: P4E8-439R (5′-GAAAAGTCTCAGGTACAACCCAGTTC-3′)
TaqMan probe: P4E8-385T (FAM 5′-AGACGGATTGACTTAGACGGGAACGGTT-3′ TAMRA).
Real-time PCR reactions were set up using the TaqMan PCR core reagent kit (Applied Biosystems)1,
with 1 μl (10–20 ng) of DNA extract, 7.5 pmol of each primer and 2.5 pmol probe in a total volume of
25 μl. Plates were cycled at generic system conditions (10 min at 95 °C and 40 cycles of 1 min at
60 °C, 15 s at 95 °C) on either of the ABI Prism 7700 or ABI 7900HT Sequence Detection Systems
(Applied Biosystems)2, using real-time data collection. Ct values lower than 40 indicated the presence
of T. palmi DNA.
4.2.2 COI sequence-based real-time PCR assay for Thrips palmi
This assay of Kox et al. (2005) was designed as a species-specific assay against T. palmi for use by the
phytosanitary authorities in the Netherlands. It was evaluated by screening the assay against 23 other
species of thrips, including 11 belonging to the genus Thrips (T. alliorum (Priesner), T. alni, T.
angusticeps Uzel, T. fuscipennis Haliday, T. latiareus Vierbergen, T. major, T. minutissimus, T.
parvispinus (Karny), T. tabaci, T. urticae, T. vulgatissimus). These were predominantly, but not
exclusively, European species.
Methodology
The Thrips palmi-specific PCR primers and TaqMan probe used in this assay are as follows:
PCR primer: Tpalmi 139F* (5′-TCA TGC TGG AAT TTC AGT AGA TTT AAC-3′)
PCR primer: Tpalmi 286R* (5′-TCA CAC RAA TAA TCT TAG TTT TTC TCT TG-3′)
TaqMan probe: TpP (6-FAM 5′-TAG CTG GGG TAT CCT CAA-3′ MGB).
* Primers have been adjusted for greater sensitivity since original publication.
(COI sequences that mismatch with the TaqMan probe in this assay have been deposited on GenBank
from a number of specimens from India identified as T. palmi on the basis of their morphology
(Asokan et al., 2007). These sequences would not produce a positive result using this assay. The
taxonomic or phylogenetic significance of this sequence differentiation currently remains unclear.)
The 25 μl reaction mixture contained 12.5 μl of 2x TaqMan Universal Master Mix (Applied
Biosystems)3, 0.9 μM each primer, 0.1 μM TaqMan probe, 1.0 μl DNA. The real-time PCR was
performed on either of the ABI Prism 7700 or ABI 7900HT Sequence Detection Systems (Applied
Biosystems)4 using the following conditions: 10 min at 95 °C; then 40 cycles of 1 min at 60 °C and 15
s at 94 °C. Ct values lower than 40 indicated the presence of T. palmi DNA.
4.2.3 ITS2 sequence-based PCR-RFLP assay for nine species of thrips including Thrips
palmi
This assay (Toda and Komazaki, 2002) was designed to separate nine species of thrips, including T.
palmi, that are found in fruit trees in Japan: Frankliniella occidentalis (Pergande), F. intonsa
(Trybom), T. hawaiiensis Morgan, T. coloratus Schmutz, T. flavus, T. tabaci, T. palmi, T. setosus
Moulton, Scirtothrips dorsalis Hood.
1, 2 The use of the brand Applied Biosystems for the TaqMan PCR core reagent kit and the ABI Prism 7700 or
ABI 7900HT Sequence Detection Systems in this diagnostic protocol implies no approval of them to the
exclusion of others that may also be suitable. This information is given for the convenience of users of this
protocol and does not constitute an endorsement by the CPM of the chemical, reagent and/or equipment named.
Equivalent products may be used if they can be shown to lead to the same results.
3, 4 The use the brand Applied Biosystems for the TaqMan Universal Master Mix and ABI Prism 7700 or ABI
7900HT Sequence Detection Systems in this diagnostic protocol implies no approval of them to the exclusion of
others that may also be suitable. This information is given for the convenience of users of this protocol and does
not constitute and endorsement by the CPM of the chemical, reagent and/or equipment named. Equivalent
products may be used if they can be shown to lead to the same results.
Methodology
The PCR primers (located in the 5.8 S and 28 S regions flanking the ITS2 region of ribosomal DNA)
used in this assay were as follows:
5′-TGTGAACTGCAGGACACATGA-3′
5′-GGTAATCTCACCTGAACTGAGGTC-3′.
T. palmi generated a 588-base-pair (bp) PCR product (longer or shorter fragments were produced from
the other species). The 20 μl reaction mixture was composed as follows: 1 μM each primer, 250 μM
dNTPs, 1 Unit of AmpliTaq Gold DNA polymerase (Applied Biosystems)5, 2 μl 10x reaction buffer
[with 25 mM MgCl2], 0.5 μl DNA. The PCR was performed in a 9600 DNA thermocycler (Applied
Biosytems)6, with the following conditions: 9 min at 95 °C, 35 cycles of 1 min at 94 °C, 30 s at 50 °C,
and 1 min at 72 °C, followed by a final extension for 7 min at 72 °C and quickly cooled to room
temperature. The PCR products were analysed by agarose gel electrophoresis.
5 μl of PCR product (without purification) was digested with the enzyme RsaI according to the
manufacturer’s instructions. Digested PCR products were separated by 2.0% agarose gel
electrophoresis.
Restriction fragment sizes produced by T. palmi when the ITS2 fragment is digested with RsaI were as
follows: 371, 98, 61 and 58 bp.
4.2.4 COI sequence-based PCR-RFLP assay for ten species of thrips including Thrips
palmi
This assay of Brunner et al. (2002) was designed to separate ten species of thrips, including T. palmi,
which are mostly, but not exclusively, pest species found in Europe: Anaphothrips obscurus (Müller),
Echinothrips americanus Morgan, Frankliniella occidentalis, Heliothrips haemorrhoidalis (Bouché),
Hercinothrips femoralis (Reuter), Parthenothrips dracaenae (Heeger), Taeniothrips picipes
(Zetterstedt), Thrips angusticeps Uzel, T. palmi, T. tabaci.
Methodology
The PCR primers (located in the mitochondrial COI gene sequence) used in this assay are as follows:
mtD-7.2F (5′-ATTAGGAGCHCCHGAYATAGCATT-3′)
mtD9.2R (5′-CAGGCAAGATTAAAATATAAACTTCTG-3′).
These primers amplified a 433-bp fragment in all the species separated by this assay. The 50 μl
reaction mixture was composed as follows: 0.76 μM each primer, 200 μM dNTPs, 1 Unit Taq DNA
polymerase, 5 μl 10X reaction buffer [with 15 mM MgCl2], 1 μl DNA. The PCR was performed in a
standard thermocycler with the following conditions: 1 min 94 °C, 40 cycles of 15 s at 94 °C, 30 s at
55 °C, and 45 s at 72 °C, followed by a final extension for 10 min at 72 °C and quickly cooled to room
temperature. To gauge the fragment size produced after amplification, 5 μl of the PCR products were
analysed by 1.0–2.0% agarose gel electrophoresis.
5 μl of PCR product (without purification) was digested with the enzymes AluI and Sau3AI in separate
reactions according to the manufacturer’s instructions. Digested PCR products were separated by
agarose gel electrophoresis.
5, 6 The use of the brand Applied Biosystems AmpliTaq Gold DNA polymerase and 9600 DNA thermocycler in
this diagnostic protocol implies no approval of them to the exclusion of others that may be suitable. This
information is given for the convenience of users of this protocol and does not constitute and endorsement by the
CPM of the chemical, reagent and/or equipment named. Equivalent products may be used if they can be shown
to lead to the same results.
Restriction fragment sizes produced by T. palmi when the COI fragment is digested with AluI and
Sau3AI are as follows:
AluI: 291 and 194 bp
Sau3AI: 293, 104, 70 and 18 bp.
5. Records
Records and evidence should be retained as described in section 2.5 of ISPM 27:2006.
In cases where other contracting parties may be adversely affected by the diagnosis, the records and
evidence (in particular, preserved or slide-mounted specimens, photographs of distinctive taxonomic
structures, DNA extracts and photographs of gels, as appropriate), should be kept for at least one year.
6. Contact points for further information
Entomology Section, National Reference Laboratory, Plant Protection Service, P.O. Box 9102, 6700
HC Wageningen, Netherlands. Telephone: +31 317 496824; e-mail: g.vierbergen@minlnv.nl;
fax: +31 317 423977.
Pest and Disease Identification Team, The Food and Environment Research Agency, Sand Hutton,
York YO41 1LZ, United Kingdom. Telephone: +44 1904 462215; e-mail:
dom.collins@fera.gsi.gov.uk; fax: +44 1904 462111.
Area EntomologÃa, Departamento Laboratorios Biológicos, Dirección General de Servicios AgrÃcolas,
MGAP, Av. Millán 4703, C. P. 12900, Montevideo, Uruguay. Telephone: +598 2304 3992; email:
ifrioni@mgap.gub.uy; fax: +598 2304 3992.
7. Acknowledgements
The first draft of this protocol was written by D.W. Collins, Pest and Disease Identification
Programme, The Food and Environment Research Agency, Sand Hutton, York, YO41 1LZ, United
Kingdom; G. Vierbergen, Dr. L.F.F. Kox, Plant Protection Service, Section of Entomology,
Wageningen, Netherlands; and Ing. Agr. N.C. Vaccaro, Sección EntomologÃa, INTA-EEA Concordia,
Argentina. Line drawings for Figure 5 were produced by S. Kobro, Norwegian Crop Protection
Institute, Norway.
8. References
Asokan, R., Krishna Kumar, N.K., Kumar, V. & Ranganath, H.R. 2007. Molecular differences in
the mitochondrial cytochrome oxidase I (mtCOI) gene and development of a species-specific
marker for onion thrips, Thrips tabaci Lindeman, and melon thrips, T. palmi Karny
(Thysanoptera: Thripidae), vectors of tospoviruses (Bunyaviridae). Bulletin of Entomological
Research, 97: 461–470.
Bhatti, J.S. 1980. Species of the genus Thrips from India (Thysanoptera). Systematic Entomology, 5:
109–166.
Bournier, J.P. 1983. Un insecte polyphage: Thrips palmi (Karny), important ravageur du cotonnier
aux Philippines. Cotonnier et Fibres Tropicales, 38: 286–288.
Brunner, P.C., Fleming, C. & Frey, J.E. 2002. A molecular identification key for economically
important thrips species (Thysanoptera: Thripidae) using direct sequencing and a PCR-RFLPbased
approach. Agricultural and Forest Entomology, 4: 127–136.
EPPO. 2008. URL: http://www.eppo.org/. Accessed 17 June 2008.
EPPO/CABI. 1997. Thrips palmi. In I.M. Smith, D.G. McNamara, P.R. Scott & M. Holderness, eds.
Quarantine pests for Europe, 2nd edition. Wallingford, UK, CAB International. 1425 pp.
Kox, L.F.F., van den Beld, H.E., Zijlstra, C. & Vierbergen, G. 2005. Real-time PCR assay for the
identification of Thrips palmi. Bulletin OEPP/EPPO Bulletin, 35: 141–148.
Mantel, W.P. & Vierbergen, G. 1996. Additional species to the Dutch list of Thysanoptera and new
intercepted Thysanoptera on imported plant material. Folia Entomologica Hungarica, 57
(Suppl.): 91–96.
Moritz, G., Mound, L.A., Morris, D.C. & Goldarazena, A. 2004. Pest thrips of the world: visual
and molecular identification of pest thrips (CD-ROM), Centre for Biological Information
Technology (CBIT), University of Brisbane. ISBN 1-86499-781-8.
Mound, L.A. & Azidah, A.A. 2009. Species of the genus Thrips (Thysanoptera) from Peninsular
Malaysia, with a checklist of recorded Thripidae. Zootaxa, 2023: 55–68.
Mound, L.A. & Kibby, G. 1998. Thysanoptera. An Identification Guide. 2nd edition. Wallingford,
UK, CAB International. 70 pp.
Mound, L.A. & Marullo, R. 1996. The thrips of Central and South America: an introduction (Insecta:
Thysanoptera). Memoirs on Entomology, International, 6: 1–488.
Mound, L.A. & Masumoto, M. 2005. The genus Thrips (Thysanoptera, Thripidae) in Australia, New
Caledonia and New Zealand. Zootaxa, 1020: 1–64.
Mound, L.A. & Morris, D.C. 2007. A new thrips pest of Myoporum cultivars in California, in a new
genus of leaf-galling Australian Phlaeothripidae (Thysanoptera). Zootaxa, 1495: 3545.
Murai, T. 2002. The pest and vector from the East: Thrips palmi. In R. Marullo, & L.A. Mound, eds.
Thrips and Tospoviruses: Proceedings of the 7th International Symposium on Thysanoptera.
Italy, 2–7 July 2001, pp. 19–32. Canberra, Australian National Insect Collection.
Nakahara, S. 1994. The genus Thrips Linnaeus (Thysanoptera: Thripidae) of the New World. USDA
Technical Bulletin No. 1822. 183 pp.
PaDIL. 2007. Pests and Diseases Image Library. URL: http://www.padil.gov.au. Accessed 18 Oct
2007.
Palmer, J.M. 1992. Thrips (Thysanoptera) from Pakistan to the Pacific: a review. Bulletin of the
British Museum (Natural History). Entomology Series, 61: 1–76.
Rugman-Jones, P.F., Hoddle, M.S., Mound, L.A. & Stouthamer, R. 2006. Molecular identification
key for pest species of Scirtothrips (Thysanoptera: Thripidae). Journal of Economic
Entomology, 99 (5): 1813–1819.
Sakimura, K., Nakahara, L.M. & Denmark, H.A. 1986. A thrips, Thrips palmi Karny
(Thysanoptera: Thripidae). Entomology Circular No. 280. Division of Plant Industry, Florida;
Dept. of Agriculture and Consumer Services. 4 pp.
Toda, S. & Komazaki, S. 2002. Identification of thrips species (Thysanoptera: Thripidae) on
Japanese fruit trees by polymerase chain reaction and restriction fragment length polymorphism
of the ribosomal ITS2 region. Bulletin of Entomological Research, 92: 359–363.
Walsh, K., Boonham, N., Barker, I. & Collins, D.W. 2005. Development of a sequence-specific
real-time PCR to the melon thrips Thrips palmi (Thysan., Thripidae). Journal of Applied
Entomology, 129 (5): 272–279.
zur Strassen, R. 1989. Was ist Thrips palmi? Ein neuer Quarantäne-Schädling in Europa. Gesunde
Pflanzen, 41: 63–67.
zur Strassen, R. 2003. Die terebranten Thysanopteren Europas und des Mittelmeer-Gebietes. In Die
Tierwelt Deutschlands. Begründet 1925 von Friedrich Dahl, 74: 5–277. Keltern, Goecke &
Evers.
Publication history
2006-04 CPM-1 added topic diagnostic protocol for Thrips palmi (2006-038)
2006-10 TPDP developed draft text
2007-05 SC approved draft text for MC
2007-06 Sent for MC under fast-track process
2007-10 SC-7 revised draft text
2007-11 SC requested TPDP to review
2008-11 SC noted draft text under TPDP review
2009-05 SC recalled draft text to TPDP
2009-11 SC approved revised draft for MC
2009-12 Sent for MC under fast-track process
2009-12 SC revised draft text for adoption via e-decision
2010-03 CPM-5 adopted Annex 1 to ISPM 27
ISPM 27. 2006: Annex 1 Thrips palmi Karny (2010)
Publication history: Last modified August 2011
