ECOLOGICAL STUDIES ON THE MEDFLY, CERATITIS CAPITATA IN APRICOT ORCHARDS IN RELATION TO NEIGHBOURING CITRUS ORCHARDS

The population fluctuation of the Mediterranean fruit fly, Ceratitis capitata (Wied.) (Diptera : Tephritidae) was studied in apricot orchards in relation to the neighbouring summer citrus orchards for three succes­sive seasons (1992 , 1993 and 1994) at Kalubia Governorate. In the meantime, the rate of larval infestation in apricot fruits was estimated in apricot orchards compared with those in adjacent citrus ones. Data of trap catches indicated that medfly population was higher in summer cit­rus orchards than in apricot orchards through the period from early March to mid-May / early June; then adults migrate to apricot orchards giving rise to high population until late July. Medfly male catches per trap per day "CTD" ranged 0.008 - 2.31,0.02 - 3.84 and 0.03-5.64 males in summer citurs orchards, while it ranged 0.0-5.24, 0.0-6.76 and 0.0 - 12.32 in apricot orchards during the three seasons respectively. The percentages of larval infestation in apricot orchards were higher in those near to citrus orchards than in far away ones during the three suc­cessive seasons. Mean percentages of medfly infestation in apricot fruits ranged 2.13 - 19_06, 1.64 - 27.55 and 12.63-77.38% in apricot or­chards neighbouring to citrus orchards compared with 0.58 - 8.17, 0.87 - 11.21 and 0.79 - 19.73% in apricot orchards far away from citrus or­chards during the three successive seasons, respectively.