Relation between Leafhopper Influxes and Synoptic Weather Conditions

Abstract

A study was made of the association of potato leafhopper influxes into Illinois with existing synoptic weather conditions. With data for 25 observed influxes during 1951?59, synoptic weather maps and climatological records were studied to obtain information during and preceding the flights on: wind conditions between the Louisiana source region and Illinois; the presence of fronts in Illinois; the extent and intensity of rainfall in the state; and prevailing temperature conditions. Results of the study indicated a strong relationship between synoptic weather conditions and leafhopper influxes. Typical meteorological conditions favoring influxes were found to be: a persistent southerly flow of maritime tropical air from the Gulf states into the Midwest for at least 36 hours prior to the Illinois influx; rainshowers or thundershowers on the days of influx; and, the presence of a front, usually a cold front, at the time of the recorded influx. From the above criteria, days favorable for influxes during 1960 were predicted. Excellent correspondence was obtained between indicated and actual dates of 1960 influxes.