Estimating the Potato Leafhopper <I>Empoasca fabae</I> (Homoptera: Cicadellidae) Overwintering Range and Spring Premigrant Development by Using Geographic Information System

Abstract

The potato leafhopper, Empoasca fabae (Harris), is a circular migratory pest of many crops in the United States that overwinters in the southern states. Northward migrant population arrival to the northern states occurs earlier in the north central states compared with northeastern states. Migrant leafhopper arrival to the north varies from year to year depending on factors influencing the development of spring migrants in the overwintering areas and on timing of weather systems capable of transporting the migrants northward. An estimate of the potato leafhopper minimum temperature survival, the geographic limits of the potato leafhopper overwintering range, leafhopper spring development in the overwintering areas, and the identification of the spring migration initiation northwards can help to predict the leafhopper arrival time in the northern states. In the current study, geographic information system (GIS) was used to estimate the potato leafhopper minimum temperature survival and premigrant development. The minimum winter temperature was estimated by overlaying minimum temperature isolines with potato leafhopper collection data taken during the winter, The geographic limits of the overwintering range were estimated using the minimum temperature survival to create a condition-based model by using ArcMap-GIS 8.2. The estimated overwintering range was larger and covered areas further north than previously estimated and included Missouri, Kansas, Kentucky, Virginia, and Maryland. The use of degree-day accumulation to estimate days of first adult emergence in the overwintering areas resulted in earliest adult emergence in the south central region. First adult emergence in south central and southeastern areas occurred before the detection of potato leafhoppers in the north central United States. These data suggested that the difference in population arrival between the north central states and the northeastern states was more dependent on factors affecting the migration and weather conditions encountered along the migration pathway.