Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 21, 2006
Publication Date: February 1, 2007
Citation: Arbogast, R.T. 2007. A wild strain of Plodia interpunctella (Hubner)(Lepidoptera:Pyralidae) from farm-stored maize in South Carolina: Development under different temperature, moisture, and dietary conditions. Journal of Stored Products Research. 43:160-166. Interpretive Summary: The need to reduce the risk posed by chemical pesticides to human health and the environment, and at the same time to protect food commodities from damage and contamination by insect pests, has prompted a substantial research effort to develop insect control strategies that reduce or eliminate the need for chemical application. Development of expert systems for predicting insect problems and recommending remedial action have made significant contributions towards this end. These computer systems incorporate the collective knowledge of many experts in a form that can be accessed and applied by those responsible for protecting food commodities. The systems also incorporate mathematical models capable of predicting population growth of storage pests. Unfortunately, relatively few population models have been developed for stored product insects, because the necessary data linking physical conditions of the storage environment to pest growth, development, and reproduction are incomplete. ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida, have determined how temperature and moisture conditions affect development and survival of the Indianmeal moth on stored corn. This moth is a major worldwide pest of granaries, food processing plants, warehouses, retail stores, and households. The information provided by this study will be used by scientists in building population models for incorporation into expert systems. These systems will in to turn be used by farmers, elevator operators, warehousemen, and extension workers to prevent or reduce damage and contamination of corn and corn products by means that will minimize pesticide risk.
Technical Abstract: The purpose of this study was to determine the duration of immature development and survivorship of Plodia interpunctella (Hübner) on maize over a range of temperatures and grain moisture contents encountered in maize stored on farms in the southeastern states (USA). Laboratory cultures were established with moths collected from farm-stored maize in South Carolina and maintained on cracked maize at 30°C and 60% r.h. The incubation period and percentage hatch of eggs was determined at 18 combinations of temperature and r.h. Hatch was < 1% at 15 and 40°C. In the range 20-35°C, percentage hatch declined as temperature increased, and the mean incubation period ranged from 3.1 to 8.5 d. Neither percentage hatch nor incubation period were affected by r.h. The relationship between mean developmental period (oviposition to adult eclosion) was well described by a quadratic polynomial that predicted a decline from 67.6 to 30.1 d as temperature increased from 20 to 31.1°C, followed by an increase to 38.5 d as temperature increased further to 35°C. The results suggest a lower temperature threshold for development near 15°C and an upper limit slightly greater than 35°C. Moisture content had a significant effect on developmental period at all the temperatures studied, but the pattern of variation with moisture depended upon the temperature.