As the first cutting of alfalfa is approaching there are several insect species to scout and monitor for. While scouting alfalfa last week I encountered what at first I thought were large populations of potato leafhoppers. However, upon closer inspection using a hand lens it was clear that they weren’t potato leafhoppers but instead aster leafhoppers. In the previous newsletter, we discussed the presence of aster leafhoppers in winter wheat. These insects are not host specific, and they feed on a wide variety of plants including alfalfa. Unlike the potato leafhopper, the aster leafhopper does not cause extensive feeding injury to leaves (hopper burn) unless very large populations are present. Aster leafhopper feeding can usually be determined by observing white spots on the plants, which is referred to as stippling. However, this type of feeding injury can also be due to twospotted spider mites.
Profile & Appearance
Adult aster leafhoppers are small at approximately 1/8 of an inch long. They have the typical leafhopper wedge shaped body that is light green to yellow in color. The adult aster leafhoppers have clear wings that cover their abdomens (Figure 1). Although present on nymphs and adults, the two distinct spots present between the eyes when viewed from above are more easily observed on adults (Figure 2). The aster leafhopper is occasionally referred to as the six-spotted leaf hopper due to the presence of the six distinct black markings that are observed when observing the front of the head (Figure 3).
Figure 1. Aster leafhopper adult side view.
Figure 2. Aster leafhopper adult top view.
Figure 3. Aster leafhopper adult front view.
There are no management recommendations currently available for aster leafhoppers in alfalfa. Alfalfa infestations of this insect are typically due the aster leafhopper being attracted to green plants in the spring. The biggest concern with aster leafhoppers is their potential to vector the aster yellows phytoplasma. The symptoms associated with this disease include yellowing of the leaves. This disease has not been reported in alfalfa in South Dakota. If you have fields that you believe may be infested with aster leafhoppers please contact Adam Varenhorst.
Photos courtesy of Varenhorst.