As winter is upon us, there are things that growers can do to deal with winter pests. Of course, this is particularly important in winter production and here in Illinois, this is primarily done in high tunnels and greenhouses. In high tunnels, no pest is worse in winter production than aphids (photo to right, K. Athey, Illinois Extension 2024). Strawberry and leafy greens can be particularly vulnerable to aphids. In winter production, biological control and organic insecticide sprays can be combined. Parasitoid wasps, while quite effective against aphids, do not do very well in colder temperatures. They are definitely better used for summer production. 

There has been some research into winter pest control. Both biological control and organic insecticide sprays were tested. Lacewings (Chrysoperla carnea) reduced aphid numbers in spinach. Minute pirate bugs (Orius insidiosus) reduced aphids on strawberries. Both of these can be ordered from several different companies including Koppert, BioBee, and Biobest. For these two insect pests organic sprays, Neemix, Sil-Matrix, and Pyganic, did not harm the predators. Pyganic was the most effective insecticide in the field. It also has a zero day PHI.

There are conventional insecticides for aphids in winter greens, Actara, Admire, Assail, Fulfill, and Movento are good choices, but they all have longer PHIs than Pyganic. Make sure you always read and follow insecticide labels.