Residual Sprays to Control Insects in Warehouses, 1983

Abstract

Abstract Three representative building materials of low economy grade were used in warehouse tests to assess the relative effectiveness of encapsulated diazinon, diazinon emulsion, and malathion emulsion spray residues against laboratory-reared mature larvae of the warehouse beetle and young adults of the cigarette beetle, the confused flour beetle, and the sawtoothed grain beetle. Squares of aluminum with kraft paper backing 1 ft2 attached with double-stick tape to press board squares of the same size, the smooth side of press-board panels measuring 2 by 4 ft, and 18- in. square concrete stepping stones were sprayed with insecticides from a Namco compressed air sprayer with a fan nozzle (no. 800067). Surfaces were wet with spray as required by the different substrates, but application was stopped before run off. Sufficient substrate was treated with each concentration used to provide eight exposure replications with each test species for aging dates of 1, 7, 14, and 28 days. Sprays were applied and insects were exposed to treated surfaces in the early morning when the 6,300 ft3 warehouse was cool; residues were aged in the warehouse with extreme ambient climatic conditions ranging from low night temp of 58°F and 90% RH to the highest day temp of 112°F and 20% RH. Twenty-five specimens of each species were contained in 7.5-cm diam fluon-treated glass cylinders to keep insects on treated surfaces of each treatment replication. Cylinders on concrete surfaces were ringed at their base with a nontoxic caulking material to prevent escape of insects, and a filter paper cover was put on cylinders to prevent escape of flying cigarette beetles. After an exposure of 2 h on treated surfaces, test insects were removed and placed on food in fresh containers. Then they were held 7 days in a room maintained at 80°F and 50% RH before mortalities were recorded. Appropriate controls were included in the test and mortalities shown in the tabulation of results were corrected for natural mortality, although few insects died in control samples.