Aphids, frequently referred to as plant lice, are one of our common insect pests of tobacco in South Carolina. The most common aphid on tobacco, and the one with which we are most concerned, is the tobacco aphid. This aphid is capable of transmitting PVY (potato virus-Y) in tobacco. This pest has been increasing in importance the past few years (with the exception of 1998), both due to increases in populations as well as virus transmission.
Aphids may occur at any time on tobacco, from the plant bed through harvest. However, it is not usually damaging in the plant beds in South Carolina. It may, however, be carried from the plant beds to the field during transplanting, and this should be avoided.
In addition to transmitting PVY, damage to tobacco by aphids is done in two ways. By sucking plant juices, the aphids make the leaves thin and light in weight. The aphids also damage the plants by depositing honeydew on the leaves as they feed. The honeydew, a sweet, sticky substance, accumulates on the leaves. A fungus, sooty mold, may develop on the honeydew. This results in improper curing. It also presents a problem in marketing, as the cured leaves may be black, crumbly, and stuck together, resulting in lower quality tobacco.
The tobacco aphid adult is a small, soft-bodied, green or red, smooth-looking aphid. It may or may not have wings. In the South, males are not needed for reproduction, and all of the aphids are females. All adult females are capable of bearing live young, called nymphs. These resemble the parent except that they are much smaller and always wingless. Populations peak around the last week of June.
Although the tobacco aphid is known to have many hosts, only a few of these are important to the aphid strain that feeds on tobacco. The most important wild host plant of the aphids in South Carolina appears to be wild mustard that grows in grain fields during late winter and early spring.
Different insecticides and different application methods are available for aphid control on tobacco. Since the list of labeled products is constantly changing, and since available products varies from state to state, there will be no mention of specific products. With all insecticides, read and follow label instructions carefully.