Seasonal abundance of the serpentine leaf miner Liriomyza trifolii and the bio efficiency of the larval ectoparasitoid Diglyphus isaea on cowpea in Alejelat region, Libya

The American serpentine leaf miner, L. trifolii (Burgess), is one of the most problematic insect pest species attacking a large number of vegetable crops, weeds, and ornamentals. The present study aimed to determine the natural abundance of the larval parasitoid D. isaea and the serpentine leaf miner L. trifolii. This study was carried out in Alejelat region during two summer seasons of 2018 and 2019 on cowpea. The highest monthly total numbers of L. trifolii larvae, D. isaea, host fed, and total killed larvae that occurred on August recording (1187, 535, 209, and 744), respectively. While the monthly average numbers recorded (862.5 ± 289.8, 341.7 ± 139.5, 123.75 ± 57.3, and 465.5 ± 194.8) for the former parameters during season 2018, respectively. On the other hand, the highest monthly total numbers of L. trifolii larvae, D. isaea, host fed, and the total killed larvae occurred on August recording (3211, 1264, 580, and 1844), respectively. While the monthly average numbers recorded (1517.5 ± 1299.6, 632 ± 438.5, 285.5, ± 201.8, and 917.5 ± 640.2) for the former parameters during season 2019, respectively. The percentage of total mortality reached 91.8%, and 87.6 in the first and the second season, respectively.