Mortality of life stages of cowpea weevil (Coleoptera: Bruchidae) exposed to low pressure at different temperatures.
Previous studies have shown that low pressure creates a low oxygen controlled atmosphere that can kill stored-product insects. The current study was conducted to determine the mortality of life stages of the cowpea weevil, Callosbruchus maculatus (F.) (Coleoptera: Bruchidae), exposed to different low pressures and temperatures for various exposure periods. The adults were the most susceptible life stage to low pressure; 99% mortality was achieved within 0.8 h at 32.5 mmHg, 30 degrees C. The pupae were the most tolerant life stage to low pressure, requiring exposure periods between 28.98 and 153.20 h at temperatures of 20-35 degrees C to achieve 99% mortality. Mortality increased with exposure time and also with increasing temperature in all life stages. Early stage eggs (3 h old) and late stage eggs (48 h old) experienced higher mortality (values for LT99 of 42.331 and 46.652 h, respectively) compared with intermediate aged eggs (24 h old; LT99 of 74.735 h) under the same conditions of low pressure and temperature. Dried beans, including cowpea, Vigna unguiculata (Walp.), are currently protected with fumigants. Application of low pressure as a pest management tool represents a potential nonchemical alternative to fumigants such as methyl bromide and phosphine for controlling the cowpea weevil and related bruchids.
Mbata
George N
GN
Department of Biology, Fort Valley State University, 1005 University Dr., Fort Valley, GA 31030, USA. mbatag@fvsu.edu
Johnson
Mario
M
Phillips
Thomas W
TW
Payton
Mark
M
D000818:Animals; D001517:Coleoptera / Q000254:growth & development*; D007300:Insect Control / Q000379:methods*; D010063:Ovum; D011312:Pressure; D011679:Pupa; D013696:Temperature; D013997:Time Factors