Experiments in the treatment of Citrus fruit by fumigation with ethylene dibromide for the control of the damage caused by the Mediterranean Fruit-fly (Ceratitis capitata (Wied.)) were conducted during 1951–52 and 1952–53.

Jaffa and Valencia oranges were found to tolerate a concentration of 18 gm./m.3 at approximately 20°C. and exposure time of 2½ hours.

Grapefruit was found to tolerate a concentration of 15 gm./m.3 at approximately 20°C. for 2½ hours' exposure. When the exposure time is prolonged to 6 hours the maximum tolerance is 8 gm./m.3

A kill of 75 per cent. of the larvae of Ceratitis inside the Citrus fruits was obtained by exposure for 2½ hours at a concentration of 15 gm./m.3

Citrus fruit for export from Israel is normally fumigated with Decco (NC13) against certain fungus diseases. The exposure in this case is 6 hours. The possibility of combining the treatment with Decco and ethylene dibromide was examined. It was found that the treatments were compatible and that, at an exposure of 6 hours, a dosage of 6 gm./m.3 of ethylene dibromide gave a kill of up to 93·5 to 96·4 per cent.

Fumigation of fruit for export, in batches of 3,000 cases at a time, showed that 6 gm./m.3 of ethylene dibromide (all other conditions being equal) killed up to 98·5 per cent. of Ceratitis larvae (provided no gas leakage occurred in the fumigation chamber). This concentration did not cause injury to Jaffa and Valencia oranges. In the case of grapefruit, slight damage occurred—especially in over-ripe fruit (during the second half of April) which was not intended for shipping.