Aphids, members of the order Homoptera, are probably the most notorious pests in the world. With well over 4000 species of aphids in this huge order, there is an aphid for everyone and nearly everyone in horticulture and agriculture may have to, at some point in time, deal with aphids. They are often one of the first pests to appear — usually very early in the season. Some of the reasons for this is due to their life-cycle but, perhaps, it is because they love tender new growth. Aphids are called plant lice by some people, though based on our experiences, this is not typical.
How They Become a Problem
The infestation process begins as winged adult aphids come in from their winter hideaways (usually the craggy bark of nearby trees) during early spring when weather is warm enough to allow their flight and migration, and this can be very early in the season. Exception to this rule, of course, will include human introductions where aphids are brought into a structure hitchhiking on purchased plants. Remember: scout new plant material thoroughly before bringing it into your greenhouse.
A Serious Pest
Winged aphids start the ball rolling. From that point on the aphids no longer have wings and those forms will not be present. If you detect some winged aphids, your population is probably in its beginning stages, however like everything else in the complicated world of pests, there are exceptions. In this case the exception is if your aphid population is in full swing, a brood of winged aphids will be developed. The reason for this is simple: the host plant is becoming overloaded and may not be able to support further aphid population growth. The colony wants to spread. In other words, if you detect plants loaded with aphids and some are winged forms, the problem is quickly going to affect nearby plants. There is no greater time to take advantage of the aphid control options available.
For the Scout
can be used preventively — which is highly recommended, especially when considering the awesome destructive potential of these pests. Chemical controls can also be effective, but great care must be taken as aphids can easily develop resistance to many pesticides.
In our opinion, if scouting is done right and if biocontrols are used preventively, aphids can be a non-issue issue for growers. Aphid control can be easily achieved, but only if aphids are understood and respected.