White Flies

I have very limited growing space for vegetables. To remedy this, I created a raised bed along a narrow walkway that sits between my deck and a 6' cedar fence. The first year I had some success growing tomatos and peppers. This past year, I added herbs. However, the entire growing space was infested with what I think were white flies. I tried, a bit too late, to spray them with insecticidal soap, but the plants were just covered with hundreds maybe thousands of these tiny little flying insects. My main question is will they overwinter here in zone 5 and therefore come back this next growing season. If so, any ideas on how to get rid of them for good?

you may never get rid of them for good. they'll just appear every year on certain plants that they like. you want to spray with a lite summer oil, especially the undersides of the plant. the flying ones you see have already matured and done their damage. it's the little larvae still on the plant that causes the damage. since your garden is dormant right now, now is the time to spray with volck oil. this is the heavy, dormant oil which will smother everything in the bed. you can't use it once the weather warms up; it will cook the plants, kind of like a stir-fry!

I've had good luck with killer bugs such as lady bugs and those little parasite wasps. I used some of each so I'm not sure what worked, but I was able to eliminate them completely. I'm in Zone 5 (or maybe Zone 6 now) in Colorado.

--Kris

Thank you both for your response. I will have to be much more diligent early on in the growing season. I will definitely try the heavy oil when the snow stops flying. I really don't like to spray anything on my vegetables if I can help it, but I think I will have to use the oil in the growing season on a consistent basis and maybe I will have some luck in keeping them at bay. I would like to introduce more beneficials which is a good thing white flys or not!

Washing, i.e., spraying plants can sometimes be used to control whiteflies. Safer-Soap, for example, helps dislodge the whiteflies from the leaves (the underside usually) but follow the label directions carefully. Plants should be washed at least weekly and more frequently during periods of heavy infestations. Regarding organic controls, whiteflies are attacked by a number of predators and parasitic wasps. Whitefly nymphs are eaten by green lacewings, lady bugs, minute pirate bugs, big eyed bugs, and damsel bugs. Some of these can be purchased at organically minded nurseries. Research what plants the organic predator also likes to be around. Plant some of these such that, when you can release the oranic predators, you will make then stay in your garden (as opposed to nibble on whiteflies for a while and then leave).

And don't use the Safer Soap or other pesticides when you release the predators--the sprays will kill the good bugs too.