Role of Natural Mortality in Boll Weevil (Coleoptera: Curculionidae) Management Programs

Abstract

Seasonal patterns of natural mortality of boll weevil, Anthonomus grandis grandis Boheman, were assessed throughout the cotton-growing season at seven East Texas locations in 1982. Proportions of mortality contributed by predators, parasites, desiccation and mortality in the egg stage varied between areas. For all sampling dates at all locations, mortality caused by predation was equal to or greater than any other mortality factor. The red imported fire ant, Solenopsis invicta Buren, was the major predator in six locations. The fire ant, Solenopsis geminate (F.), was the dominant predator in only one field. Percentage of predation was lower when increased desiccation occurred on the same sampling date. Mortality induced by desiccation fluctuated between 0 and 51%. Percentage of parasitism was 50% during August and early September. Total mortality exceeded 80% throughout the growing season at Austonio and Huntsville. Peak total mortality was >90% at all locations during August through early September. Mortality at Austonio decreased from 92% in mid-September to 44% in November. High summer mortality of the boll weevil contributes to the success of management strategies used against boll weevils in the spring and fall.