Seasonal Fluctuations of the Green Peach and Turnip Aphids on Commercial Greens Crops in Oklahoma1

Abstract

Aphids are among the most destructive pests on greens crops, particularly Myzus persicae on spinach and Rhopalosiphum pseudobrassicae on crucifers. M. persicae was active during the entire year, being present on spinach from Oct. to May, inclusive, and occurring in light infestations during the summer on a large number of cultivated and wild plants. The heaviest populations on spinach generally occurred on the winter and spring crops. This sp. was collected from 47 spp. of crop and wild plants. Collections of R. pseudobrassicae were limited to crucifers, lettuce and bush beans. It occurred on cruciferous greens crops from Aug. to Dec. and during the spring. Temperature was the critical factor in aphid development. Subnormal temperatures in the early fall, mid-fall, and spring, and above normal temperatures in the late fall and winter appeared to favor development. Sub-freezing temperatures did not cause an immediate reduction in the population unless they were near 0[degree]F.