DISTRIBUTION AND MOBILITY OF POTATO LEAFHOPPER IN COMMERCIAL ALFALFA FIELDS IN MICHIGAN

摘要

Potato Leafhopper (PLH) is one of the most important insect pests of alfalfa; it can cause significant loss of both yield and forage quality. We examined the distribution of PLH in commercial alfalfa fields in Michigan to see if the insect-plant system possessed characteristics amenable to precision control. We sampled PLH weekly using a sweep net, at stations located on a 4000 m2 grid in the fields. Measurements were repeated weekly throughout the growing season. Because of this repeated sampling, insect movement can be inferred from changes in population density. Damaging populations were observed at two of the three field sites and these populations were asymmetrically distributed in the fields. In addition, one of the fields, PLH populations showed significant concentrations and the alfalfa crop could tolerate low populations. The combination of these factors means that control by precision spraying may be possible. Additionally, the apparent mobility of the insects indicates that the "trap crop" concept currently being explored may be an excellent tool for eliminating residual PLH populations with minimal expense and insecticide use.