While scouting winter wheat fields throughout Central and Eastern South Dakota last week, there were several fields that were exhibiting the tell-tale signs of leafhopper feeding injury. After a little additional scouting, it was determined that the fields were infested with large populations of the aster leafhopper (Figure 1). Aster leafhoppers are capable of producing feeding injury that is referred to as “hopper burn.” However, the severity of the injury from aster leafhoppers is much less than that observed when plants are fed on by potato leafhoppers. Populations of aster leafhoppers are normally small in the spring, but occasionally can reach large and observable populations. There are no set economic thresholds for this pest to date. Aster leafhoppers are generalists and will feed on many species of plants including grasses and some garden vegetables.
Figure 1. Aster leafhopper adult. Courtesy: A. Varenhorst.
Aster Leafhopper Description
Adult aster leafhoppers are small at approximately 1/8 of an inch long. They have a wedge-shaped body that is light green to yellow in color. The adult aster leafhoppers have clear wings that cover their abdomens. 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 2. Top view of the aster leafhopper adult head. Note the two-distinct black circular spots between the eyes. Courtesy: A. Varenhorst.
Figure 3. Front view of the aster leafhopper adult head.
Courtesy: A. Varenhorst.
Aster leafhoppers have piercing-sucking mouthparts that are used to feed on the phloem of plants. The aster leafhopper mouthparts disrupt plant cells during feeding which results in stippling (white or yellow spots on the leaves). Excessive feeding results in yellow discoloration of the leaf and the characteristic symptoms of “hopper burn”. Hopper burn often is mistaken for drought stress as the leaves of affected plants begin to turn yellow and will dry out beginning at the leaf tip (Figure 4).
Figure 4. Wheat leaf exhibiting aster leafhopper feeding injury (white spots).
Courtesy: D. Cottrill.
Vector of Aster Yellows Virus
Aster leafhoppers are also competent vectors of aster yellows phytoplasma. However, the presence of the leafhopper is not always an indicator that aster yellows will also be present. The adult leafhoppers must acquire the phytoplasma from previously infected plants during a 30 minute or longer feeding. The aster yellows phytoplamsa then takes approximately two weeks to incubate in the aster leafhopper before it can be transferred to new plants. Although acquisition of the phytoplasma takes a considerable time, once ingested and incubated aster leafhoppers remain infectious. Aster yellows symptoms are similar to those of Barley yellow dwarf virus (BYDV). Economic losses in wheat have been associated with Aster yellows infections in North Dakota, which were observed when large populations of the aster leaf hopper and high incidence of aster yellows were present.
There are currently no set management recommendations for aster leafhoppers. We recommend scouting wheat for their presence and making management decisions based on the presence of observable feeding injury or aster yellows symptoms. Direct feeding by the aster leafhopper hasn’t been associated with yield loss, but large populations may be an indicator of potential aster yellow issues.
- Knodel, J. 2015. Aster leafhoppers in winter wheat. North Dakota State University Extension.