**2.1 Insect rearing technique**

Red palm weevil*, R. ferruginous* adults were obtained from cocoons collected from infested date palm trees in the Salhia district (Sharkiya governorate, Egypt). A large number of cocoons were put into oblong opaque –white plastic boxes ( 21 x10.5x 7 cm in length, width and high respectively) covered with tight-fitting and perforated lids. Cocoons were kept in wet toweling until adult emergence.The newly emerged adults were sexually differentiated. Newly laid eggs from the adult culture were collected using a 0.2 mm brush and inserted into round plastic Petri dishes (50 mm diameter x 20 mm high) containing tissue paper soaket in Benzoate solution, which was renewed daily. The Petri dish had a screw cap and uniformly spaced perforations (2 mm diameter) around the surface of the box including lid and bottom.

The hatched larvae were maintained in plastic cups (250 ml capacity) containing 5g of artificial diet as described by Rahalkar *et al.,* (1985). The plastic cups were covered with muslin cloth and kept at controlled laboratory conditions (27°C and 85% RH). Daily inspection was carried out until eggs hatched and the larval and pupal stages were completed. After emergence, adult weevils were transferred into wire screen cages containing pieces of suger cane as food.

### **2.2 Irradiated treatments**

Adults weevils, 2 weeks after emergence, irradiated with 15, 20 Gy of gamma radiation using gamma cell (60 Cobalt –Source), installed in the Middle Eastern Regional Radioisotope Center for the Arab Countries, Cairo, Egypt, with the dose rate of 1 Gy / 1.95 sec.
