Oct. 10, 2007
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Thrips specialist Cheryle O'Donnell is coordinating the UC Davis workshop. (Photo by Kathy Keatley Garvey) |
DAVIS—A three-day workshop on thrips, tiny winged insects that cause so much damage to flower and vegetable crops that they can pose a biosecurity threat, is scheduled Oct. 15-17 in the Harry Laidlaw Jr. Honey Bee Research Facility, University of California, Davis.
The workshop is funded by a biosecurity grant from the U.S. Department of Agriculture (USDA), awarded to two UC Davis entomologists—grant writer Cheryle O’Donnell and principal investigator Michael Parrella—and thrips biologist Gerald Moritz of the Martin-Luther University Halle-Wittenberg, Halle, Germany.
“Thrips cause billions of damage to our agricultural crops in the United States,” said O’Donnell, the workshop coordinator. Thrips puncture and suck nutrients from plants and also feed on other insects and mites.
In 1996, Cuba’s Fidel Castro accused the United States of aerially releasing Thrips palmi over potato fields.
“Of the more than 5000 species of thrips known in the world, some are serious pests, and some are beneficial as pollinators and predators,” said O’Donnell, who has studied thrips since 1997 and recently completed her doctorate in entomology from UC Davis. Some thrips transmit plant diseases, such as the tomato spotted wilt virus and the impatiens necrotic spot viruses.
“To monitor agricultural crops effectively, it’s important to be able to identify them, but it’s difficult to do so without understanding thrips taxonomy and identification,” she said.
The Thysanoptera Workshop (thrips belong to the scientific classification order, Thysanoptera) is geared toward agricultural identification inspectors at ports of entry, Extension specialists, general entomology diagnosticians and graduate students focusing on thrips or taxonomy.
O’Donnell, Parrella and Moritz and UC Davis entomologist Diane Ullman will be among the speakers at the workshop, along with USDA and California Department of Agriculture scientists and other specialists. Topics include the biology, ecology and identification and exotic species of concern to the United States; and USDA exotic pest interceptions.
“Thrips are so small—one millimeter long or less--that they’re like a speck,” O’Donnell said. “Inspectors see larvae, eggs and adults on plant material coming in, but unfortunately, the identification keys are built for the adult female. There are no distinctive morphological characteristics available to separate species at the life stage of eggs, larvae and adult males.”
“That’s why molecular information is a must to determine the species of individuals, especially those intercepted at ports of entry,” said O’Donnell, who works in the Parrella lab and also identifies thrips for the Bohart Museum of Entomology on the UC Davis campus.
The team will train diagnosticians on collecting, preparing the collection for molecular identification, and slide mounting. Training also will include identifying thrips using Lucid keys, a software management tool.
Enrollment is limited to 30 participants. Registration is $550. Only six slots remain, with registration closing Friday, Oct. 12.
For more information, e-mail O’Donnell or phone (530) 752-4784); access the online workshop; or access her interactive thrips identification tool, her master’s thesis.
 Thrips palmi
Common name: Melon thrips
Distribution: North America (Pacific United States and Florida), South America, Africa, Australia and Asia
Host Plants: Cucurbitaceae (cucumber, squash, pumpkin, melon family). Leguminosae (pea or bean family). Solanaceae (potato, eggplant, tomato, chili pepper, petunia family). Other hosts include chrysanthemum, cyclamen, dahlia, carnation and orchid.
Damage: Leaves become silvered, brown, curl, and become necrotic. Flowers distorted and drop prior to fruit development. Terminal shoots distorted and stunted. Fruits scarred by feeding during fruit development. (Photo and text by Cheryle O'Donnell) |
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 Heliothrips haemorrhoidalis
Common name: Greenhouse thrips
Distribution: Widespread in Europe, North America, South America, Australia, Africa and Asia.
Host Plants: Breeds on the leaves of a wide range of plants in the greenhouse and landscape, but not on herbs or soft leaves. Primarily feeds on the underside of leaves. Damage: Leaves become distorted, curled under, silvered and turn brown. Plants become stunted, flowers become discolored. Fruit surfaces become bronzed. (Photo and text by Cheryle O'Donnell)
Click to enlarge photos |
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--Kathy Keatley Garvey
Communications specialist
(530) 754-6894
