Flower Thrips (WFTs - Frankliniella occidentalis) are often a problem
year after year in greenhouse production. They are tough to manage during all
crop growing stages, but even more so when crops are flowering. They can be
very difficult to control, particularly in flowers and buds due to their
preference for tight, dark places. WFTs prefer feeding on pollen, young foliage,
flowers and buds. Feeding can cause curled, distorted, puckered and chlorotic
foliage. Typically, irregular white spots form, and the leaf surface may appear
silvery or have a stippled appearance. New growth and flowers typically are
deformed and discolored with feeding scars. WFTs also have the ability to
transmit viruses such as impatiens necrotic spot virus (INSV) and tomato
spotted wilt virus (TSWV).
Western Flower Thrips
the chance of high populations of WFTs resulting in crop injury, start control
measures early and use an integrated approach. Listed below are basic thrips
new shipments of plants and remove or treat plants that contain thrips.
with a clean growing area. Old plant material and “pet” plants are a perfect
place for thrips to hide out between crops. Remove stock plants and leftover
plants from the growing area. These can serve as not only as hosts for thrips
but also as reservoirs for viruses spread by thrips. Be sure to control weeds
in and around the perimeter of the greenhouse.
(opening size < 200 microns) on doors and vents can help prevent thrips from
moving into the greenhouse from outside crops or weeds.
crops regularly for the presence of thrips and physical damage caused by their feeding.
Use sticky cards to monitor populations early in the crop cycle, before flowers
or buds are present. Include Thripline™
ams pheromone lure from Bioline™ pest
control products with your sticky cards to increase thrips movement, which will
provide an earlier and more accurate population assessment.
use of chemical controls:
o Begin spray rotations
when populations are low and before flowers or buds are present.
o First apply products
that are effective on adults and immature stages such as Avid® miticide/insecticide,
and then rotate to an insect growth regulator following an appropriate
rotational program such as Scimitar® GC
and Flagship® 25WG insecticide on