EVALUATION OF ELITE DRY BEAN GERMPLASM FOR RESISTANCE TO POTATO LEAFHOPPER, EMPOASCA FABAE, IN MICHIGAN

摘要

Empoasca fabae, also known as potato leafhopper (PLH), is currently the most abundant insect pest of dry beans in Michigan. In the 1980's PLH replaced tarnished plant bugs and aphids as the major insect pest of dry beans and they continue to be an annual threat that reduce bean seed yield and quality. By evaluating PLH incidence in a range of both commercial varieties and breeding lines, we can assess PLH preferences and determine possible sources of resistance to the pest. By monitoring the differences in the number of PLH nymph numbers present, inferences can be made as to oviposition (egg-laying) and feeding preferences of the insects (antixenosis interactions) (Schaafsma et al., 1998). In addition, the number of nymphs present can indicate antibiosis interactions where the bean genotype causes direct deleterious effects to the pest. Another method for assessing pest resistance is to evaluate plant damage caused by the pest. PLH causes a specific set of symptoms known collectively as "hopperburn" that are evaluated on a 1-5 scale for leaf curl and leaf burn (Murray et al., 2001).The objective of this study was to evaluate potato leafhopper feeding preference and/or avoidance in a diverse range of dry bean varieties and breeding lines under field conditions in Michigan.