Relative retention of adult sawtoothed grain beetles in potential food baits

Abstract

Abstract Retention of adult sawtoothed grain beetles, Oryzaephilus surinamensis (L.), in freshly cracked corn, wheat and sorghum; rolled oats or freshly cut kibbled carobs, was evaluated in the laboratory via choice tests. Retention in a food mixture (cracked corn, cracked wheat, rolled oats and kibbled carobs; 1:1:1:0.2 parts by weight), used for detecting stored-product insects on farms and in country elevators in Kansas, was compared with that in cracked corn, cracked wheat, cracked sorghum, kibbled carobs and rolled oats. Choice tests were performed using 80 unsexed adults in 41.5 cm diameter wooden arenas with 5-g samples of one or more food materials in total darkness at 27°C and 45% rh . Retention of O. surinamensis adults in cracked corn and rolled oats was significantly and consistently higher than in cracked wheat, cracked sorghum or kibbled carobs. There were no significant differences in the number of adults retained in cracked corn and rolled oats in the majority of tests. Adult retention in the food mixture and cracked corn was similar, and twice as many adults were retained in these foods compared with rolled oats. Equal number of adults were retained in the food mixture with and without carobs. The consistent and high retention of adults in cracked corn or rolled oats indicated that these foods are promising as baits for detecting residual populations of O. surinamensis adults in empty grain stores, warehouses or outdoors.