The Effects of Propylene oxide Fumigation on the Mortality of Plodia interpunctella (Hubner) (Lepidoptera: Pyralidae)

Abstract

This study was carried out in 2014-2015 at Kahramanmaraş Sütçü İmam University, Faculty of Agriculture, Department of Plant Protection, Entomology Laboratory. This study aims to evaluate the viability of propylene oxide (PPO) as an alternative fumigant to methyl bromide (MeBr) for the efficient control of Plodia interpunctella (Hubner) (Lepidoptera: Pyralidae) and to model the mortality rates of P. interpunctella insects using different regression techniques. The biological effectiveness of PPO was assessed across all life stages of P. interpunctella during a brief exposure period (4 hours) under three conditions: normal atmospheric pressure (PPO alone), low pressure (PPO+Vacuum), and an atmosphere enriched with carbon dioxide (CO2) (PPO+CO2). For all PPO treatments, PPO was directly introduced into the fumigation chamber at seven or more concentrations using different micro-syringes of different volume ranges: 2.5-25 µl l-1, 1.5-45 µl l-1, 1.5-30 µl l-1, and 0.5-15 µl l-1 for eggs, larvae, pupae, and adults, respectively. The results indicate that 100% mortality was observed in eggs at concentrations of 25 µl l-1, 20 µl l-1 and 20 µl l-1; in larvae at concentrations of 45 µl l-1, 30 µl l-1 and 40 µl l-1; in pupae at concentrations of 30 µl l-1, 15 µl l-1 and 25 µl l-1; and in adults at concentrations of 15 µl l-1, 10 µl l-1 and 10 µl l-1 for the PPO alone, PPO+Vacuum, and PPO+CO2 treatments, respectively. The results obtained from the developed regression models for insect mortality reveal that these models generally exhibited a better fit when described by exponential and third-order polynomial functions. In summary, this study indicates that PPO treatments hold significant promise for rapid insect control, particularly in the case of the Indian meal moth, rendering them invaluable for quarantine purposes.