Irradiation Disinfestation of Dry Dates and the Possibility of Using Combination Treatments

The disinfestation effect of 70-krad gamma radiation on artificially infested packed dates (Zahdi variety) relative to fumigation with methyl bromide, and the effect of combination treatment of gamma radiation (0, 35, 70, 105 krad) and heat (40°C) on Oryzaephilus surinamensis adult mortality, have been studied. Treatment with 70-krad gamma radiation, or fumigation with methyl bromide, led to a complete and satisfactory insect disinfestation of dates, though disinfestation by 70 krad required a comparatively long period to bring about 100 % mortality, in contrast to the more or less direct killing effect of methyl bromide. However, the combination treatment (particularly 35 krad + 40°C) appears very promising as it reduces by half the period of time required for killing all O. surinamensis adults, and simultaneously ensures full sterility and complete inhibition of reproduction in this insect. (author)