Thus far in the growing season (if we can call it that!), two vegetable problems have surfaced as the most common ones by far. First – cold temperature damage, and second – aphids in the greenhouse.
Most of the questions I have fielded relate to aphids on tomatoes in the greenhouse, and many growers want to know how to control them biologically. The Greenhouse Manager’s Guide to Integrated Pest Management in Northern New England (available online here, if you don’t have a hard copy) offers some useful suggestions about biological control of many pests including aphids, and our colleagues at the University of Massachusetts have put together a nice fact sheet on managing aphids in greenhouses.
The biggest trick for biological control of aphids is to know what species of aphid you are dealing with. But how am I to know whether it’s a foxglove aphid, a melon aphid, a green peach aphid, or a potato aphid?? You can’t tell by color, or size. But, it turns out that it’s not that difficult to tell them apart, assuming you have a dissecting microscope (which most of our extension offices do, if you don’t at your farm!). When I asked Alan Eaton, UNH Extension Entomologist, for some guidance, he not only helped me, but also volunteered to put it in a little video as a grower resource. The video is located here, on youtube… check it out, and then go scout for aphids. I hope you don’t find any!