Killing Aphids



What You May Not Know About Killing Aphids

There is more to killing aphids than merely spraying chemicals on your plants. In order to successfully exterminate aphids while minimizing the effects of chemicals on surrounding plants and insects, you need to understand what you are up against.



Aphids have long been the bane of farmers who, in trying to minimize widespread damage to commercial crops, have expended huge amounts of time and money trying to control the insect’s activities. Farmers can also testify to the havoc these bugs wreak amongst grain, vegetable and fruit crops, as well as the blight they pass along to alder, beech and hickory trees. 

Unlike insects such as the weevil or cutworm, who either go after one type of plant or cause a singular form of damage, aphids engage in several modes of destruction.

An aphid colony will attach itself to the underside of a leaf, and by so doing cause it to dry out- which in turn causes the leaf to curl downward. Not only does it ruin the leaf, but also provides increased cover for the insects.

Aphids rob plants of their sap, and exude a sticky substance that clogs leaf surfaces, which soon becomes a breeding ground for fungi and mold. The sticky honeydew coating aphids leave behind also reduces the effectiveness of applied fungicides.

Some types of aphids transmit viruses, while others harm vegetation with their toxic form of saliva.

Many experts in both the fields of entomology and horticulture stress the importance of not killing aphids just because they’re there, but letting nature take its course. For a time it was believed that the “honeydew” an aphid exudes had some sort of beneficial properties. Others now point to the fact that insects such as lacewings and ladybird beetles can control concentrated groups of aphids.



Environmental factors, including fungal infection and damp weather, should be counted on to stem the tide, as well. There are even some gardeners who swear by the “spray-em-with-wtaer” approach, which does guarantee the bugs won’t return to that particular bush. The problem is, they simply move on to another plant to continue feeding and destroying.

The same thing can be said for the pruning and disposal of discovered infestations. You’ve killed them after the fact. The key is to discover and destroy them when the colonies are still small, before they have a chance to spread.

In the end, farmers and gardeners have to rely on the only tried-and-true solution: killing aphids with chemical and/or biological agents. It seems the only way to deal with the aphid, an insect that breeds profusely, doesn’t scare easily when disturbed, and when finished destroying one crop will fly to the next to continue feeding.

Home remedies abound, but one of the best involves making a solution of lukewarm water and 2 teaspoons of mild soap, which you then spray under the leaves. This application will cause the aphids to dehydrate.

Another solution, which can be applied weekly, will clog the aphid’s respiratory spiracles. Mix together three parts water, a couple drops of soap, and one part vegetable oil.

Store-bought insecticidal soaps accomplish much the same thing, though in a different manner, by suffocating and dehydrating the aphids.

Commercially available IGR’s (insect growth regulators) such as Neemix and Azatin may take a little more time, but prevent aphids from molting and sexually maturing.

Pyretherins, which come in spray form, are also available.

Grow seedlings inside a covered and protected area. When they are later planted they are more likely able to resist aphid-related damage.

Before planting vegetables, inspect nearby vegetation such as mustard weeds for aphids. Also look for signs of ant trails. Ants tend to congregate around aphids and not only feed on the honeydew they exude, but protect the aphids from predators. To block the ants’ progress, attach one of several available forms of open-faced adhesives around the plant or tree, which will stop ants from traveling to the aphids.