Regional Variation in Host Infestation and Larval Abundance of Cucurbit Fruit Flies in Major Cucurbit-Growing Areas of Bangladesh
Ruhul Amin
Department of Entomology, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.
Md. Mizanur Rahman
Department of Entomology, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.
Mohammed Sakhawat Hossain
Department of Entomology, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.
Ayesha Akter
Department of Entomology, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.
Fatema Begum
Department of Plant Pathology, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.
Rebaka Sultana
Department of Horticulture, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.
Md. Emam Hossain *
Department of Entomology, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.
*Author to whom correspondence should be addressed.
Abstract
Cucurbit fruit flies are among the most damaging insect pests of cucurbit vegetables, but comparative information on host-associated infestation across major production areas of Bangladesh remains limited. A field survey was conducted in 12 upazilas across six districts, namely Dhaka, Bogura, Narsingdi, Manikganj, Cumilla and Jashore to describe variation in plant infestation, fruit infestation and larval abundance among locally important cucurbit hosts. In each crop–location combination, 10 plants were examined, and fruit infestation and the number of larvae per infested fruit were recorded. Plant infestation ranged from 10 to 60%, whereas mean fruit infestation ranged from 14.75 to 39.03%. The highest fruit infestation was recorded in sponge gourd at Dhamrai, Dhaka (39.03 ± 15.75%), followed by sponge gourd at Singair, Manikganj (33.53 ± 4.04%), bitter gourd at Belabo, Narsingdi (32.07 ± 18.27%) and bitter gourd at Monirampur, Jashore (31.71 ± 10.24%). Sweet gourd repeatedly supported comparatively high larval abundances, reaching 2.40 ± 0.17 larvae fruit⁻¹ at Burichang, Cumilla, 2.33 ± 0.29 at Singair and 2.17 ± 0.29 at Belabo. In contrast, several crop–location combinations with high fruit infestation contained relatively few larvae per fruit, indicating that field infestation and larval abundance captured different components of host–pest association. The survey demonstrates marked spatial and host-associated variation and supports location-specific monitoring, sanitation, trapping, fruit protection and coordinated integrated pest management in cucurbit production in Bangladesh.
Keywords: Cucurbitaceae, Tephritidae, Bangladesh, cucurbit crops, host association, plant infestation, fruit infestation, larval abundance, field survey, integrated pest management