Possible control of fungal and insect infestation of date fruits using ozone

Saeed S. Al-Ahmadi, Reda A. Ibrahim and Salama A. Ouf      

Department of Biology, Faculty of Science, Taibah University, Madinah Mounawara, P.O. 30002 Saudi Arabia.

ABSTRACT: Fruits of ten date palm cultivars, collected from the area of Almadinah Almunawwarah, Saudi Arabia were tested for their fungal and insect infestation. Fifteeen fungal species and three insect pests were recorded from the tested cultivars. The fungal infestation of date cultivars can be arranged as follow: Baeiddy > Anbrah > Rothan > Berni > Ajwah > Shalaby > Safawy > Labban > Rabbiah > Sokai. Aspergillus, paecilomyces, Penicillium and Fusarium were the dominant genera. The recovered insects were Oryzaephilus surinamensis, Oryzaephilus Mercator, Cadra furcatella baptella. The highest insect damages were recorded in the case of Safway cultivar infested with C. furcatella baptella (8.16%) followed by Sokai and Barni cultivars infested with O. surinamensis (7.83 and 6.33%, respectively). The growth of most test fungi was significantly decrease on exposure to 4 ppm ozone for 120 minutes and steady drop in growth rate was achieved on dose elvevation to 8 ppm accompanied with extending the exposure time. Ozone concentration of 8 ppm was lethal for all fungal species, when the exposure time extended to 180 or 240 minutes. There was a steady increase in mortality of larvae and adults of O. surinamensis reaching 100% at 30 ppm ozone delivered for 6 hours. Eggs and pupae were relatively sensitive to ozone as compared to larvae and adults where 100% mortality was achieved using 7 ppm ozone for one hour.

KEYWORDS: Ozone; date fruits; infestation, fungi; insects; Oryzaephilus surinamensis

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