Suppression of Cadra cautella (Lepidoptera: Pyralidae) development by phytosanitary irradiation doses and their impacts on physiochemical and microbiological quality of dates.

Abstract

Cadra cautella is a serious insect pest of stored figs and dates. The irradiation sensitivity of different development stages of C. cautella and large-scale testing of the proposed irradiation quarantine doses (50-500 Gy), were investigated. The impact of a PI dose of 400 Gy on the physiochemical and microbiological quality of dry dates (Bartamoda cv.) stored at room temperature was also investigated. An irradiation dose of 100 Gy prevented egg hatching in the F1 generation when 1-3 days old eggs were irradiated. Irradiation doses of 200 and 300 Gy prevented adult emergence when 2^nd and 4^th instar larvae were irradiated. When the pupae stage was irradiated, an irradiation dose of 400 Gy prevented the hatchability of F1 generation, indicating that this stage was the most radio-tolerant. The results of large-scale testing of the proposed phytosanitary irradiation dose (400 Gy) applied to 18, 0000 pupae resulted in no reproduction (zero hatching of F1 generation). There were no significant differences in the physiochemical properties of stored dates during the storage period at room temperature. Stable ESR signal intensity was recorded for 6 months in all parts of the irradiated fruits, and the intensity was highest in the kernel. The PI dose of 400 Gy also slightly reduced all microorganisms' counts. In conclusion, the dose level of 400 Gy stopped the reproduction potential of C. cautella. and they maintained the quality characteristics of dry date Bartamoda fruits during storage at room temperature for 6 months in tightly closed packages.