Seasonal Occurrence of Fruit Flies and Their Infestation Rates on Pomegranate Fruits at Assuit and Fayoum Governorates

Abstract

The peach fruit fly, Bactrocera zonata (Saunders), and the Mediterranean fruit fly, Ceratitis capitata (Wiedmann) are harmful tephritid insects that infesting the Egyptian fruits. This study was conducted to determine the occurrence and damage rates of these fruit flies on pomegranate fruits at Assuit and Fayoum governorates under various cultivated types of mixed-host or aggregated orchards. Moreover, the study extended to estimate some biological aspects of B. zonata rearing on pomegranate fruits under laboratory conditions. At Assuit governorate, the highest peak of B. zonata and C. capitata populations were observed during the 3rd week of October and 4th week of October with means of 2.33 and 9.13 flies/trap/week on the mixed-host orchards, respectively, while, on the pomegranate aggregated orchards, the highest peak of B. zonata and C. capitata populations were observed during the 4th week of October and 3rd week of November with means of 3.42 and 3.17flies/trap/week, respectively. At Fayoum governorate, the highest peak of B. zonata and C. capitata populations were observed during the 2nd and 4th weeks of October with means of 10.17 and 8.17 flies/trap/week on the mixed-host orchards, respectively, while, on the pomegranate aggregated orchards, the highest peak of B. zonata and C. capitata populations were observed during the 4th week of September with means of 7.67 and 1.83 flies/trap/week, respectively. At the mixed-host orchards of Assuit, the infestation percentages averaged7.39,9.15 and 5.65% for Manfaloti, Baladi and Nab Al-Jaml varieties, respectively, while, on the aggregated orchards, the infestation percentages averaged 2.17, 5.45 and 6.04%, respectively for the same varieties. At Fayoum, the infestation percentagesaveraged6.40, 7.96 and 6.25% for Manfaloti, Baladi and Wonderful varieties, respectively on the mixed-host orchards, while, on the aggregated orchards, Baladi variety fruits were only infested with a mean percentage of 6.42%.Under laboratory conditions, B. zonata females were capable to attack pomegranate fruits that were in healthy state or that were wounded, while, C. capitata females failed to attack the healthy fruits and succeeded to infest only the wounded fruits of both two tested varieties. Also, a significant difference was observed among the mean no. of obtained pupae/ infested fruits of various pomegranate varieties after exposing to fertile females of B. zonata which may due to the significant difference among thier fruit firmness. The shortest and longest duration of total immature stages averaged 21.17 and 23.36 days on the Baladi and Taefi fruits, respectively. Despite the limited occurrence of both fruit flies and the low infestation rates, the study suggested that attention should be paid against pomegranate orchards by application of control procedures for avoiding rebuilding new generations of both fruit flies that could attack the successive ripe crops.