Thrips palmi Karny
New pathway from South America
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Name: Thrips palmi Karny
Animalia: Arthropoda: Insecta: Thysanoptera: Thripidae
Common Names: palm thrips; melon thrips
Palm thrips have been intercepted in Miami, Florida (U.S.A.) on roses from the Western Hemisphere for at least the second time. This has not previously been perceived as a high-risk pathway.
Issues of Concern: Palm thrips were intercepted on roses from Colombia by APHIS-PPQ in February 2000 and in January 1995. This species has been intercepted on roses from other parts of the world about 20 times. Palm thrips on new world commercial roses represents a new pathway; roses from the western hemisphere were previously viewed as low-risk. Specific methods used for the inspection of roses are considered critical to successful detections.
The spatial distribution of Thrips palmi in Korea is also apparently increasing (EPPO Reporting Service 2000, No. 11), "expanding towards the north, due to its wide host range and lack of effective control measures".
Hosts: Thrips palmi is polyphagous, primarily feeding on Orchidaceae, Cucurbitaceae and Solanaceae. It has been reported on aubergines (Solanum melongena), Benincasa hispida, Capsicum annuum, cotton (Gossypium spp.), cowpeas (Vigna unguiculata), cucumbers (Cucumis sativus), Cucurbita spp., melons (Cucumis melo), peas (Pisum sativum), Phaseolus vulgaris, potatoes (S. tuberosum), sesame (Sesamum indicum), soybeans (Glycine max), sunflowers (Helianthus annuus), tobacco (Nicotiana tabacum) and watermelons (Citrullus lanatus). Flowers: citrus, mango. Weeds: Vicia sativa, Cerastium glomeratum and Capsella bursa-pastoris. Greenhouses: aubergines, Capsicum annuum, chrysanthemums (Dendranthema morifolium), cucumbers, Cyclamen, Ficus and Orchidaceae.
Vector(s)/Dispersal: T. palmi is reported to be a vector of viruses related to TSWV in Japan and Taiwan.
Asia; Africa; Australasia; North America (Hawaii, Florida); Central America and Caribbean (Antigua, Barbuda, Barbados, Dominica, the Dominican Republic, Grenada, Guadeloupe, Haiti, Martinique, Puerto Rico, St. Lucia, St. Kitts and Nevis, Trinidad and Tobago); South America
Quarantines: Thrips palmi is an EPPO A1 quarantine pest and CPPC A2 pest.
T. palmi is difficult to detect at low densities in consignments. They are fast moving and extremely small (approx. 1.5 mm adult length). Pale thrips such as T. palmi need to be sampled on a dark surface; detections on cut flowers can be made by 'banging' flowers on a well-lit appropriately colored surface. Inspectors should collect specimens from the sampling surface using a paint brush moistened with alcohol from the vial into which they will be placed.
Larvae are very pale and cryptic, and are difficult to detect even on dark surfaces. This is also a life stage commonly encountered by inspectors. Since thrips are rapidly driven off fresh commodities by heat, a Berlese funnel technique may be preferable while also being less destructive to inspected ornamentals.
A Berlese technique for thrips detection has been successfully employed at the Port of San Francisco, California. A bank of 6 funnels is employed, and cut flowers are taken apart and inserted. Thrips can be detected in a matter of hours. This method is destructive, and is currently used only on commodities from customer baggage, which are already destined to be destroyed. This system does work well, and serves to increase inspector awareness.
Thrips palmi is one of several thrips species exhibiting high levels of pesticide resistance on ornamental plants. Insecticides with systemic activity may be preferable.
Source: APHIS-PPQ, Miami, Florida and Baltimore, Maryland (USA)
UF/FDACS Featured Creature
A pest data sheet is available in Quarantine Pests for Europe, Second Edition, 1997, pp. 538-542, CAB International, Wallingford UK.