Monday, December 16, 2013

Onion Thrips

As a common problem in the vegetable, onion thrips is a major insect pest not only of onions and leeks but also attacks broccoli, cabbage, carrots, cucumbers, garlic, melons, papaya, pineapple, squash and tomato. (Note - thrips refers to one or many.) 

The damage from the feeding results in whitish or silvery streaking on the leaves. Black droppings from the insect may also be seen. Thrips populations are often greater in the warmer months of the year.

There are predators and parasites that attack the thrips but often are not effective for proper control. Sometimes washing with a stream of water will help. Plants, of course, will tolerate a certain level of infestation causing only cosmetic damage. If injury threatens crops loss, then treatment is called for. Synthectic pyrethroid insecticides such as Warrior (lambdacyhalothrin) and Ammo (cypermethrin) are effective in controlling onion thrips.

Bulb Onion Production in Hawaii by R.Hamasaki and H. Valenzuela is a publication available on the CTAHR website.