Thermal death kinetics of fifth-instar Plodia interpunctella (Lepidoptera: Pyralidae).
Authors:
Johnson, J.A. Wang, S. Tang, J. USDA, ARS
Source:
Journal of economic entomology. 2003 Apr., v. 96, no. 2, p. 519-524.
NALT Subjects:
heat treatment radio waves insect control temperature duration heat tolerance mortality mathematical models diapause stored product protection
Issue Date:
Apr-2003
Abstract:
Heat treatments have been suggested as alternatives to chemical fumigants for control of postharvest insects in dried fruits and nuts. Conventional forced hot air treatments heat product too slowly to be practical, but radio frequency treatments are capable of more rapid product heating. While developing radio frequency heat treatments for dried fruits and nuts, the heat tolerance of nondiapausing and diapausing fifth-instar larvae of the Indianmeal moth, Plodia interpunctella (Hubner), was determined using a heating block system developed by Washington State University. Both a 0.5th order kinetic model and a classical empirical model were used to estimate lethal exposure times for temperatures of 44-52°C for nondiapausing fifth-instar larvae. We obtained 95% mortality at exposures suitable for practical radio frequency treatments (less than or equal to 5 min) with temperatures of 50 and 52°C. Diapausing larvae were significantly more tolerant than nondiapausing larvae at the lowest treatment temperature and shortest exposure, but differences were not significant at more extreme temperature-time combinations. Previous studies showed that fifth-instar larvae of the navel orangeworm, Amyelois transitella (Walker), were more heat tolerant than either diapausing or nondiapausing Indianmeal moth larvae. Consequently, efficacious treatments for navel orangeworm would also control Indianmeal moth.
