Influence of Cultivar, Nitrogen, and Frequency of Insecticide Application on Vegetable Leafminer (Diptera: Agromyzidae) Population Density and Dispersion on Snap Beans

Effect of snap bean, Phaseolus vulgaris L., cultivar, nitrogen fertilizer level, and frequency of permethrin application on vegetable leafminer, Liriomyza sativae Blanchard, density and dispersion was investigated in field plots during the fall seasons of 1983 and 1984. ‘Eagle’ had significantly fewer leafmines than ‘Nemasnap’. Nitrogen fertilizer level did not significantly affect leafminer density, whereas frequency of permethrin application significantly affected leafminer density. Nitrogen, permethrin application, and leafminer density had no discernable effect on snap bean yield, although ‘Eagle’ produced a significantly greater yield than ‘Nemasnap’. Leafminer dispersion was quantified with Taylor’s power law and Iwao’s patchiness regression. Leafminer dispersion was slightly contagious and not influenced by cultivar, nitrogen level, or permethrin application. A sequential sampling plan was developed from pooled data of both seasons.