Evaluating the Effectiveness of Treating Wheat Flour with ECO2-Fume Fumigant, Gamma Irradiation and Microwave Heating in Controlling Adults and Larvae of the Saw-Toothed Grain Beetle, Oryzaephilus surinamensis and the Effect of These Treatments on Some Flour Components

Abstract

The aim of this study was to evaluate the effectiveness of treating wheat flour with ECO₂-Fume® fumigant (mixture of phosphine and carbon dioxide), gamma irradiation, and microwave heating in controlling adults and larvae of the Suriname sawfly beetle. Wheat flour was exposed to ECO₂-Fume in Shona Qalyoub (Qalyubia Governorate, Egypt), and flour samples were exposed to gamma irradiation at the National Center for Radiation Research and Technology, and microwave oven under laboratory conditions. ECO₂-Fume fumigant at a concentration of 25, 30, 40 and 50 g/m³, with exposure for three days was used. The mortality rate was 100% for adults and larvae, when applied at a rate of 50 g/m³. The decline rate in the number of adults in the first generation was 100%, and there was no emergence of adults when treatment was made at the larval stage. Gamma irradiation was used at doses of 200, 400, 600, and 800 Gray. The highest mortality rate was 100% when adult insects were exposed to 800 Gray, ten days after treatment, and the larval mortality rate was 100%, five days after treatment at the concentrations of 800 and 600 Gray. In addition, population decrease rate (%) of adults of the first generation and larvae was 100% with all concentrations used. Microwave energy was used against adults and larvae of the Suriname saw beetle by exposing it to three different microwave powers, namely 180, 300, and 450 watts, for different exposure durations (20, 40, 60, 80, 100 and 120 seconds). The death rate reached 100% within 120 seconds with 450 watts. Regarding the effect of previous treatments on the main chemical components of wheat flour, the results generally showed slight differences in the protein, carbohydrates and fats content in wheat flour treated with gas at 50 g/m³ and gamma rays at 800 Gray. Whereas, in the case of microwave treatment at 450 W, significant differences in protein, carbohydrate and fat content were recorded when compared with the control treatment.

Keywords:

Stored products, insects, fumigant, radiation, microwave.