Comparison Between Two Physical Methods to Control the Stored Dates Fruit Mites, Tyrophagus putrescentiae (Schrank) and Rhizoglyphus robini Claparede (Astigmata: Acaridae)

Abstract

Date fruit is considered one of the most important fruits crop, that helps in the increment of national income. During storage, date fruits face a lot of problems such as infestation with insects, diseases and mites. The most damaging mite species are Tyrophagus putrescentiae (Schrank) (Astigmata: Acaridae) and Rhizoglyphus robini Claparede (Astigmata: Acaridae). Therefore, this work aims to evaluate two physical control methods, gamma radiation and ozone gas treatment in controlling these two mites. The two mites were irradiated with doses of 0 (control), 100, 200, 300 and 400 Gy in a source of Cobalt-60 type Indian Gamma cell with a dose rate of 0.7967 k Gy /hr. to control eggs and mobile stages. Obtained results concluded that the mites' mortality percentage increases by increasing irradiation doses and the dose for controlling 100% of the two tested mites' species was 400 Gy. While exposing the mites stages to concentrations of 0 (control), 100, 200, 300 and 400ppm of ozone gas, the results showed that the mites mortality percentage increases by increasing ozone concentrations and/or exposure period. The results indicated that ozone has the potential to control the tested mites, particularly at 200 ppm in just 4 hrs.exposure period and 99% at 400 ppm at the same exposure time. The results clearly showed that the mobile stages were more susceptible to radiation and ozone than the egg stage. Also, although radiation and ozone are safe and environmentally friendly methods of pest control, and effective to control the two mites' species with low risk but ozone control was faster and more efficient.