Question
I have a huge infestation of greenhouse white flies in my veg and flower garden. It seems almost hopeless this year. Do the flies return next year from the soil or will they go away after the hard winters in Pa. I live in Altoona, Pa.

Answer
A hard winter will normally kill them off. The only problem in mild winters is that their eggs will winter-over.

My recommendation is to use an insecticidal oil spray. These products are organic and will suffocate all existing whiteflies and their eggs. I always apply it as a dormant spray on bushes and evergreen plants in late winter, and on my vegetable plants as soon as they begin to flower in late spring. You can continue using it as needed according to the instructions all through the growing season if needed.

Gardens Alive, an on-line garden product company, sells several excellent organic sprays including Oil Away and Pyola. Both are just as effective, and can usually be applied throughout the growing season. Just follow the directions on the bottle.

Attached are the websites for each product. If you prefer, you can purchase similar products at your local garden center or nursery.

http://www.gardensalive.com/product.asp?pn=2340&ss=Oil%20Away

http://www.gardensalive.com/product.asp?pn=8101

By the way, you can also use an insecticidal soap. These products are made specifically for vegetables and houseplants, and will not burn the foliage. Attached is another link for this product.

http://www.gardensalive.com/product.asp?pn=2816&ss=insecticidal%20soap

Good luck, and please write again if I can ever be of assistance.

Regards,

Mike