Abstract: Potato Leafhopper
Small Group Session
Bill Lamp, an entomologist from Maryland, explained the life cycle, biology, and management of potato leafhopper, Empoasca fabae. The potato leafhopper is a pest of many agriculturally important plants, including potatoes, beans, alfalfa, soybeans, and apple. It overwinters in the southeastern U.S. on pine trees and moves north during the spring and summer. The early migrants reproduce best on deciduous trees, and the weather conditions during the migration and reproduction on trees influence the abundance of leafhoppers on crop plants. The amount of injury also depends on the occurrence of large populations of leafhoppers with susceptible stages of host plants. Densities of leafhoppers decline as natural enemies increase and host conditions decline in late summer.
Potato leafhopper injures plants by feeding on vascular tissues and injecting saliva into the plant veins. Mechanical damage and the saliva cause abnormal cell growth, disrupting the normal function of the phloem. This results in lower rates of photosynthesis and reduced yields, and sometimes even death of the plants and complete crop loss.
Preventive approaches for managing the potato leafhopper are limited. Natural enemies do not reduce pest numbers until after the damage has occurred. Host plant resistance exists in some crops, but it may not hold up in severe outbreaks. Cultural controls, such as changing times of planting or harvest or intercropping with non-hosts, have disadvantages. Because of the year-to-year variations in populations, the best strategy remains sampling the plants for leafhoppers and applying natural or synthetic insecticides if justified by leafhopper densities.
Discussion: Potato Leafhopper
Bill Lamp noted that red clover and alfalfa are good hosts for potato leafhoppers and that movement of leafhoppers into vegetable crops may be stimulated by cutting other hosts in neighboring fields.
Leafhoppers can be monitored by counting the nymphs per leaf, per sweep sample, or per sticky trap. However, because the adults are so highly mobile, area-wide measurements of leafhopper densities and information about weather systems bringing them north might be better predictors.
Wayne Hansen, an organic farmer from Connecticut, commented on potato varieties, such as ‘Kennebec’ and ‘Blossom’ that were most resistant to leafhopper damage in his experience.