Some Background


They are often the first natural predators to appear — usually very early in the season. Some of the reasons for this are due to their aphid reproduction cycle but, perhaps, it is because they love tender plant growth. Aphids are called plant lice by some people, though based on our experiences, this is not typical for most aphids.
How They Become a Problem

They usually stay on the newest growth and follow it upward as the plant develops — through the budding and flowering stages.
The infestation process begins as winged adult aphids emerge from their winter hideaways (usually the craggy bark of nearby trees) during early spring when the weather is warm enough to allow their flight and migration. This can be very early in the season.
Of course, human introductions where aphids are brought into a structure by hitchhiking on purchased plants will be an exception to this rule.
Remember: scout new plant material thoroughly before bringing it into your greenhouse. If infected plants are introduced, you might face an infestation quickly.
Exponential Growth

To further compound the speed in which aphids can multiply, the nymphal or immature stages are entirely female and then reproduce further parthenogenetically, which means they have no need to mate.
Adding insult to the grower’s injury, the nymphal stages are born with the next brood within them already, a condition called paedogenesis.
To aphids, the combination of these abilities spell exponential growth potential — to growers it means trouble if counteraction to naturally repel aphids or get parasitic wasps involved is not taken immediately.
A Serious Pest

This last condition, if the aphid population grows large enough to support ants, can make organic control of woolly apple aphid or green peach aphid even more challenging.

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 winged forms, the problem is quickly going to affect nearby plants. There is no greater time to control aphids.
Some Advice to Control Aphids

Aphids aren’t usually difficult to spot, though they go undetected by too many growers. Unfortunately, growers notice the ants or cast skins before seeing the pests themselves.
This is unnecessary, though, as the first aphids should be easily noted with proper scouting. Early presence of aphid predators like beneficial insects or lady beetles can avert greater damage.
For the Scout

Since aphids tend to congregate on the growing tips and flower buds, they can be easier to spot, the scout should know where to look and not be stuck searching for tiny individuals. The color of these three to six mm pests can range from yellow to red, green and blue to gray, and even black to white and fuzzy-looking.
Most species have two horn-like structures, called cornicles, on the posterior end of their abdomens, flanking a small caudal tail (they have a total of three things on their butt).
Their antennae are rather long and are swept back toward their rear along the sides of their body. In combination, these features can aid in their identification and determine whether they are parasitized aphid forms.
Some Solutions for Aphid Control

Chemical controls, such as insecticidal soaps, horticultural oil, or neem oil, can also be effective, but great care must be taken as improper use can kill beneficial insects.
In our opinion, if scouting is done right and if ladybug larvae or green lacewing larvae are used preventively, aphids can be a non-issue for growers. Effective aphid reproduction management ensures healthy crops.
Aphid control can be easily achieved, but only if aphids are understood and respected.