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EPPO Standards
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DIAGNOSTIC PROTOCOLS FOR REGULATED PESTS
THRIPS PALMI
PM 7/3(1) English
oepp
eppo
European and Mediterranean Plant Protection Organization
1, rue Le Nôtre, 75016 Paris, France
APPROVAL
EPPO Standards are approved by EPPO Council. The date of approval appears in each individual standard. In the terms
of Article II of the IPPC, EPPO Standards are Regional Standards for the members of EPPO.
REVIEW
EPPO Standards are subject to periodic review and amendment. The next review date for this EPPO Standard is decided
by the EPPO Working Party on Phytosanitary Regulations.
AMENDMENT RECORD
Amendments will be issued as necessary, numbered and dated. The dates of amendment appear in each individual
standard (as appropriate).
DISTRIBUTION
EPPO Standards are distributed by the EPPO Secretariat to all EPPO member governments. Copies are available to any
interested person under particular conditions upon request to the EPPO Secretariat.
SCOPE
EPPO Diagnostic Protocols for Regulated Pests are intended to be used by National Plant Protection Organizations, in
their capacity as bodies responsible for the application of phytosanitary measures, to detect and identify the regulated
pests of the EPPO and/or European Union lists.
In 1998, EPPO started a new programme to prepare diagnostic protocols for the regulated pests of the EPPO region
(including the EU). The work is conducted by the EPPO Panel on Diagnostics and other specialist Panels. The objective
of the programme is to develop an internationally agreed diagnostic protocol for each regulated pest. The protocols are
based on the many years of experience of EPPO experts. The first drafts are prepared by an assigned expert author(s).
They are written according to a “common format and content of a diagnostic protocol” agreed by the Panel on
Diagnostics, modified as necessary to fit individual pests. As a general rule, the protocol recommends a particular means
of detection or identification which is considered to have advantages (of reliability, ease of use etc.) over other methods.
Other methods may also be mentioned, giving their advantages/disadvantages. If a method not mentioned in the protocol
is used, it should be justified.
REFERENCES
EPPO/CABI (1996) Quarantine Pests for Europe, 2nd edn. CAB International, Wallingford (GB).
IPPC (1993) Principles of Plant Quarantine as Related to International Trade. ISPM no. 1. IPPC Secretariat, FAO,
Rome (IT).
IPPC (1999) Glossary of Phytosanitary Terms. ISPM no. 5. IPPC Secretariat, FAO, Rome (IT).
FAO (1997) International Plant Protection Convention (new revised text). FAO, Rome (IT).
OEPP/EPPO (1999) EPPO Standards PM 1/2(8) EPPO A1 and A2 lists of quarantine pests. In: EPPO Standards PM1
General phytosanitary measures, pp. 5-17. OEPP/EPPO, Paris (FR).
EU (2000) Council Directive 2000/29/EC of 8 May 2000 on protective measures against the introduction into the
Community of organisms harmful to plants or plant products and against their spread within the Community. Official
Journal of the European Communities L169, 1- 112.
DEFINITIONS
Regulated pest
A quarantine pest or regulated non-quarantine pest.
Quarantine pest
A pest of potential economic importance to the area endangered thereby and not yet present there, or present but not
widely distributed and being officially controlled.
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OUTLINE OF REQUIREMENTS
EPPO Diagnostic Protocols for Regulated Pests provide all the information necessary for a named pest to be detected
and positively identified by a general expert (i.e. an entomologist, mycologist, virologist, bacteriologist etc.) who is not
necessarily a specialist on the organism or its taxonomic group. Each protocol begins with some short general
information on the pest (its appearance, relationship with other organisms, host range, effects on host, geographical
distribution and its identity) and, then, gives details on the detection, identification, comparison with similar species,
requirements for a positive diagnosis, list of institutes or individuals where further information on that organism can be
obtained, references (on the diagnosis, detection/extraction method, test methods).
EXISTING EPPO STANDARDS IN THIS SERIES
This is a new series.
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EUROPEAN AND MEDITERRANEAN PLANT PROTECTION ORGANIZATION
ORGANISATION EUROPEENNE ET MEDITERRANEENNE POUR LA PROTECTION DES PLANTES
PM 7/3(1) English
Diagnostic protocols for regulated pests
THRIPS PALMI
Specific scope
Specific approval and amendment
This standard describes a diagnostic protocol for Thrips palmi.
First approved in 2000-09.
______________________________
Introduction
Thrips palmi is a polyphagous pest especially of Cucurbitaceae and Solanaceae. It appears to have originated in
Southern Asia and to have spread from there during the 20th century. It is now present throughout Asia and is
widespread in Central America and the Caribbean. Otherwise, it occurs locally in North and South America, Africa and
Oceania. It is not present in Europe but there have been several outbreaks in The Netherlands which were subsequently
eradicated. For more general information about T. palmi, see EPPO/CABI (1996).
T. palmi is almost completely yellow. Its identification is hampered by its small size and great similarity with other
yellow species of Thrips.
Identity
Name: Thrips palmi Karny
Synonyms: Thrips leucadophilus Priesner
Thrips gossipicola Ramakrishna & Margabandhu
Chloethrips aureus Ananthakrishnan & Jagadish
Thrips gracilis Ananthakrishnan & Jagadish
Taxonomic position: Insecta, Thysanoptera, Terebrantia, Thripidae, Thripini
Bayer computer code: THRIPL
Quarantine pest: EPPO A1 list no. 175; EU Annex designation I/A1
Detection
Where the climate is suitable, T. palmi is an outdoor pest of aubergine (Solanum melongena), white gourd (Benincasa
hispida), capsicum (Capsicum annuum), cotton (Gossypium spp.) cowpea (Vigna unguiculata), cucumber (Cucumis
sativus), courgette (Cucurbita pepo), melon (Cucumis melo), pea (Pisum sativum), phaseolus bean (Phaseolus vulgaris),
potato (Solanum tuberosum), sesame (Sesamum indicum), soybean (Glycine max), sunflower (Helianthus annuus),
tobacco (Nicotiana tabacum) and watermelon (Citrullus lanatus). In glasshouses, economically important hosts are
aubergine, capsicum, florists' chrysanthemum (Dendranthema x grandiflora), cucumber, Cyclamen, Ficus and
Orchidaceae. T. palmi can be carried on plants for planting and fruits of host species and on packing material.
During inspection of plant material for the presence of T. palmi, attention must be paid to silvery feeding scars on leaf
surfaces of host plants, especially alongside the mid-rib and veins. Heavily infested plants are characterized by silvered
or bronzed appearance of the leaves, stunted leaves and terminals, and scarred and deformed fruits.
T. palmi has six developmental stages, which are found in three different environments:
egg
: in the leaf, flower and fruit tissue;
larva I : on the leaves, flowers and fruits;
larva II : on the leaves, flowers and fruits;
propupa : in the soil;
pupa I : in the soil;
adult
: on the leaves, flowers and fruits.
Individual specimens can best be collected in a fluid called AGA which is a mixture of 10 parts of 60% ethyl alcohol
with 1 part glycerine and 1 part of acetic acid. To collect thrips specimens from plant parts such as cut flowers, the
Berlese method can be used. This uses a funnel with a sieve on top of which plant material is placed. The top of the
funnel is covered with netting. The bottom leads into a receptacle containing 10% alcohol. The funnel is placed under
an electric lamp (60 W) and the heat and light make any thrips present in the plants escape towards the receptacle. After
8 h (for cut flowers), the contents of the receptacle are checked under the microscope.
For storage, the specimens should be transferred to 60% ethyl alcohol and kept in the dark, preferably at temperatures
well below 0°C to prevent loss of colour.
Identification
Identification of thrips is performed on adults, since there are no adequate keys for the separation of species based on
the characteristics of eggs, larvae or pupae. However, the presence of larvae in samples can give important additional
information on development on host plants. For microscopic examination, adult thrips should be mounted on
microscope slides. For routine identifications, a water-soluble mountant is rapid and relatively inexpensive. The
following five steps for mounting thrips are according to Mound & Kibby (1998):
1. Transfer the specimens from the collecting fluid into clean 70% ethyl alcohol.
2. If the specimens are reasonably flexible, attempt to open the wings and straighten the antennae using micropins.
3. Place a drop of Hoyers Mountant (see below) on to a cover slip (e.g. 13 mm diameter). Place a thrips into this drop,
ventral side uppermost, and gently lower a slide onto the drop. Invert the slide as soon as the mountant has spread
sufficiently.
4. Place immediately into an oven at 35-40°C. Leave for 6 h before examining.
5. Leave in the oven for about 3 weeks to dry the mountant, then ring with nail varnish and label appropriately.
Hoyers Mountant (mixture) has the following composition (in 50 mL of water): gum arabic - 30 g, chloral hydrate 200 g, glycerine - 20 mL.
T. palmi belongs to the family Thripidae, which includes about 1700 species in 260 genera. In most species, the
antennae have seven or eight segments and the forewings (if present) are usually slender, with two longitudinal veins
each bearing a series of setae. The genus Thrips contains more than 200 species from all parts of the world. Members of
the genus have only 2 pairs of ocellar setae. The antennae have seven or eight segments and segments III and IV have
forked trichomes or sense cones. The pronotum has two pairs of major postero-angular setae. The tarsi are 2-segmented.
The abdominal tergites V-VIII have paired ctenidia laterally and the sternites and pleurotergites are set with or without
accessory setae (see Table 1; Figs 1 and 2).
Identification of the adults can be carried out with keys. Bhatti (1980) and Palmer (1992) published good and reliable
keys for the identification of species occurring in the Asian tropics. The key of Priesner (1964), including the European
species, covers T. flavus Schrank for the female and T. alni Uzel for the male. Palmer et al. (1989) give only 12 species
of economic importance. Nakahara (1994) provides keys for species from the Americas.
Detailed descriptions of T. palmi are given by Bournier (1983), Sakimura et al. (1986) and zur Strassen (1989).
Sakimura et al. (1986) give seven major diagnostic characters to distinguish T. palmi from the other known species of
the genus Thrips:
1. Clear yellow body without any greyish or brownish blotch, but with thick, blackish body setae.
2. Ocellar setae situated outside ocellar triangle.
3. Metanotal sculpture striated in the mesial area and converges posteriorly.
4. Abdominal tergite II with four lateral setae.
5. Abdominal sternites without accessory setae.
6. Abdominal tergite VIII with comb complete.
7. Male sternites III-VII each with a transverse glandular area.
See Table 2, and also Fig. 3 for diagrammatic representation of these and other diagnostic features.
Comparison with similar species
Very close to T. palmi are the Indian species T. alatus Bhatti and T. pallidulus Bagnall (Palmer, 1992). In T. alatus the
metanotal sculpture does not converge posteriorly and in T. pallidulus this sculpture is medially reticulate.
Common species occurring in Europe, which may be confused with T. palmi are T. alni Uzel, T. flavus Schrank and T.
tabaci Lindeman (zur Strassen, 1989). T. alni, only known from Alnus, differs from T. palmi in some characteristics of
the setation of the abdominal tergites in the female and the oval glandular areas on the abdominal sternites in the male
(T. palmi: broad transverse areas). T. flavus can be discriminated in having the ocellar setae inside the ocellar triangle.
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T. tabaci has three lateral setae on tergite II (T. palmi: 4) and lacks pores on the metanotum (T. palmi: two pores
present). The length of antennal segment VI for T. palmi is 42-48 µm, whereas for T. flavus it is 54-65 µm.
Like T. tabaci, T. nigropilosus Uzel, the chrysanthemum thrips, has three lateral setae on abdominal tergite II and has
no pores on the metanotum. Additionally T. nigropilosus has dark abdominal markings (T. palmi: no dark markings)
and it has abdominal tergites IV-V with 2 pairs of median setae more than 0.5 times as long as median length of these
tergites (T. palmi: less than 0.3 times).
Requirements for a positive diagnosis
The procedures for detection and identification described in this protocol should have been followed. The characters of
the genus Thrips (listed in the section Identification and in Table 1) should have been determined to be present. The
characters that distinguish T. palmi from similar species (listed in the section Identification and in Table 2) should have
been determined to be present.
Report on the diagnosis
A report on the execution of the protocol should include:
• information on the origin of the infested material;
• magnitude of the infestation (how many individual pests found; how much damaged tissue);
• measurements and drawings or photographs of the morphological features of the genus and species required for a
positive diagnosis;
• comments on the certainty or uncertainty of the identification.
Preserved specimens of the pest should be retained.
Further information
Further information on this organism can be obtained from:
Invertebrate Identification Team, Central Science Laboratory, Sand Hutton, York YO41 1LZ (UK).
Entomology Section, Plantenziektenkundige Dienst, P.O. Box 9102, 6700 HC Wageningen (Netherlands).
Acknowledgements
This protocol was originally drafted by:
G. Vierbergen, Entomology Section, Plantenziektenkundige Dienst, P.O. Box 9102, 6700 HC Wageningen
(Netherlands).
D. Collins, Invertebrate Identification Team, Central Science Laboratory, Sand Hutton, York, YO41 1LZ (UK).
References
Bhatti JS (1980) Species of the genus Thrips from India (Thysanoptera). Systematic Entomology 5, 109-166.
Bournier JP (1983) Un insect polyphage: Thrips palmi, important ravageur du cotonnier aux Philippines. Cotonnier et
Fibres Tropicales 38, 286-288.
EPPO/CABI (1996) Thrips palmi. In: Quarantine Pests for Europe, 2nd edn, pp. 538-542. CAB International,
Wallingford (GB).
Mound LA & Kibby G (1998) Thysanoptera. An Identification Guide, 2nd edn. CAB International, Wallingford (GB).
Nakahara S (1994) The genus Thrips of the New World. USDA Technical Bulletin no. 1822. USDA, Washington (US).
Palmer JM (1992) Thrips (Thysanoptera) from Pakistan to the Pacific: a review. Bulletin of the British Museum
(Natural History). Entomology Series 61, 1-76.
Palmer JM, Mound LA & du Heaume GJ (1989) CIE Guides to Insects of Importance to Man. Vol. 2. Thysanoptera.
CAB International, Wallingford (GB).
Priesner H (1964) Ordnung Thysanoptera (Fransenflugler, Thripse). Bestimmungsbucher zur Bodenfauna Europas 2, 1242 (in German).
Sakimura K, Nakahara LM & Denmark WA (1986) A thrips, Thrips palmi Karny (Thysanoptera: Thripidae).
Entomology Circular 280. Dept. of Agriculture and Consumer Services, Division of Plant Industry, Gainesville
(US).
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zur Strassen R (1989) [What is Thrips palmi? A new quarantine pest for Europe.] Gesunde Pflanzen 41, 63-67 (in
German).
Table 1 Characters of the genus Thrips
Antenna
Head
Pronotum
Forewing
Abdominal tergites V to VIII
Abdominal tergite VIII
Leg
Comprising 7 or 8 distinct segments; segments III and IV with (Fig 2.1; Fig 3.1)
forked (‘cow horn’) trichomes or sense cones
With 2 pairs of ocellar setae (II and III; pair I missing) and with (Fig 2.2)
line (undulating) of postocular setae
With 2 pairs of posteroangular setae
(Fig 2.3)
1st vein – row of setae with gaps (European species)
(Fig 2.4)
With ctenidia (combs – each comprising a series of ridges)
(Fig. 1)
With ctenidia posterior to and medial to the spiracles
(Fig 2.5)
Tarsi are two-segmented
Table 2 Characters of Thrips palmi
Body colour
Head: ocellar setae pair III
Antennal segment VI
Pronotum
Metanotum
Thrips palmi
Clear yellow with no dark areas on the
head, thorax or abdomen: antennal
segments I and II are pale
Situated outside the ocellar triangle (Fig
3.2)
42-48 µm in length (Fig. 3.1)
With 3 pairs of small equi-sized
posteromarginal setae
With a pair of metanotal pores
(campaniform sensillae); with striate
sculpturing, converging posteriorly (Fig
3.4)
Similar species
Situated inside the ocellar triangle - T.
flavus
54-65 µm in length - T. flavus
No pores - T. tabaci and T. nigropilosus
sculpturing does not converge posteriorly
- T. alatus
medially reticulate - T. pallidulus
Abdominal markings
No dark markings
Dark markings - T. nigropilosus
Abdominal tergite II
With 4 lateral setae (Fig 3.6)
3 lateral setae - T. tabaci, T. nigropilosus
Abdominal segment IV and V Tergite with 2 pairs of median setae less Tergite with 2 pairs of median setae more
than 0.3 times as long as median length of than 0.5 times as long as median length of
the tergite
the tergite - T. nigropilosus
Abdominal tergite VIII
With complete posteromarginal comb of
microtrichia (Fig 3.7)
Abdominal tergite IX
With 2 pairs of pores (anterior and
posterior) (Fig 3.8)
Abdominal pleurotergites
Ridges without microtrichia (Fig 3.5)
Forewing – vein I
With 3 (sometimes 2) distal setae (Fig 3.3)
Male : sternites III to VII
With transverse glandular areas (Fig 3.9)
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Fig. 1 Location of general characters of a terebrantian thrips.
antenna
ocellar setae
soies ocellaires
eye/oeil
ocelli
postocular setae
soies à l'arrière de l'oeil
pronotum
forewing
aile antérieure
posteromarginal setae
soies le long du bord
postérieur
1st vein
1ère nervure
mesonotum
2nd vein
2ème nervure
metanotum
central metanotal seta
soie au centre du métanotum
forewing setae
soies de l'aile antérieure
combs (ctenidia)
crêtes (cténides)
tergite (dorsal) sternite (ventral)
spiracle
pleurotergite
anal pore
pore anal
posteromarginal comb
crête le long du bord
postérieur
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Fig. 2 Characters of the genus Thrips sp.
(1) antenna: segments III et IV with
forked ("cowhorn") sense cones
antenne: segments III et IV avec
cônes sensitifs fourchus ("en
cornes de vache")
(2) head: with 2 pairs of ocellar setae
(pair I missing)
tête avec 2 paires de soies ocellaires
(paire I manquante)
ocellar setae pair III
paire III de soies ocellaires
ocellar setae pair II
paire II de soies ocellaires
forked sense cone
cône sensitif fourchu
(4) forewing: 1st vein - row of setae with gaps in
distal half
aile antérieure: 1ère nervure - rangée de soies
avec des espaces dans la moitié distale
(3) pronotum: 2 pairs of posteroangular setae
pronotum: 2 paires de soies aux angles
postérieurs
(5) abdominal
tergite
VIII:
spiracle
lying anterior and lateral to ctenidium
tergite
abdominal
VIII:
spiracle
antérieur et latéral au cténide
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Fig. 3 Characters of Thrips palmi.
(1) antenna: 7 segments; length of
segment VI = 42-48 µm
antenne: 7 segments; longueur du
segment VI = 42-48 µm
(2) head: position of ocellar setae pair III
tête: position de la paire III de soies ocellaires
(3) forewing: 3 distal setae on 1st vein
aile antérieure: 3 soies distales
sur la 1ère nervure
distal setae
soies distales
segments I and II pale
segments I et II pâles
(4) metanotum/métanotum
(9) male: glandular areas on
abdominal sternites III to VII
mâle: zones glandulaires sur les
sternites abdominaux III à VII
(5) pleurotergite
metanotal pore
pore du métanotum
striate sculpture converging
posteriorly/sculpture striée
convergeant vers l'arrière
(6) abdominal tergite II: 4 lateral setae
tergite abdominal II: 4 soies latérales
(8) abdominal tergite IX
tergite abdominal IX
(7) abdominal tergite VIII
tergite abdominal VIII
2 pairs of pores
2 paires de pores
posteromarginal comb complete
crête le long du bord postérieur complète
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