Distribution of Bactrocera cucurbitae (Coquillett) and its Natural Enemies in Sindh

Abstract

The Melon fruit fly Bactrocera cucurbitae (Coq.) is considered as one of the major insect pests of cucurbit vegetables throughout the world which mostly depends on host cues for its feeding and development. A proper monitoring and host suitability is key for its management. Hence, the present study was undertaken to assess the population fluctuation of B. cucurbitae and its natural enemies on different cucurbit vegetables at Hyderabad and Shaheed Benazirabad, two main vegetable growing areas of Sindh. Eight cucurbit vegetables i.e., pumpkin gourd, bottle gourd, sponge gourd, ridge gourd, Indian squash, bitter gourd, pointed gourd and cucumber were tested against B. cucurbitae and its parasitoids population because of their key role in its management. The obtained data indicated that the highest population of B. cucurbitae was recorded at district Shaheed Benazirabad as compared to district Hyderabad as relatively higher population of B. cucurbitae was observed during the year 2022 than 2023. Correlation results revealed that temperature (r=0.56 to 0.75) and relative humidity % (r=0.13 to 0.27) showed significant and positive effect on the population build-up of the flies on the cucurbits during both years. Moreover, two parasitoids, i.e., Trybliographa daci (Weld) and Diachasmimorpha longicaudata (Ashmead) were also recorded from the collected pupae of fruit flies. Trybliographa daci was found the dominant parasitoids over Diachasmimorpha longicaudata. It was also noted that maximum population of natural enemies were found at Hyderabad than Shaheed Benazirabad. As per correlation results, temperature showed a significant and positive influence on the B. cucubitae population recorded on various vegetables, whereas as weak to moderate effect of relative humidity was recorded. Therefore, it was concluded that maximum population of B. cucurbitae during both years was recorded on bottle gourd and sponge gourd, whereas Shaheed Benazirabad area suffered more damage than Hyderabad.