Population Abundance of the Serpentine Leaf Miner Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) on Four Winter Host Plants

Abstract

Background: The American serpentine leafminer, L. trifolii (Burgess), is one of the most problematic insect pest species attacking large number of vegetable crops, weeds and, ornamentals. Objectives: The purpose of this study is to investigate population abundance and host plant preference of L. trifolii on four winter host plants under Libyan conditions. Methods: Four winter host plants were studied [broad bean (Veciafaba), pea (Pisum sativum), fenugreek (trigonella finum gradum) and snow thistle (Sonchus oleraceus)]. The experimental field was about 1600m2 which divided to 12 equal plots (4 plots for each plant). Hundred leaflets infested with L. trifolii were taken from each host plant. Samples were kept in plastic bags and transferred to be examined in the laboratory. Number of living L. trifolii larvae were counted and recorded. Results: Four winter host plants were targeted for this study [broad bean (Veciafaba), pea (Pisum sativum), fenugreek (Trigonella foenum graecum) and snow thistle (Sonchus oleraceus)] during the growing season 2018/2019 in Alejelat region. L trifolii showed low populations in December on all studied host plants. then, developed high populations in February and March then the population decreased till the end of the growing season.  L trifolii recorded four peaks of abundance on all host plants, except snow thistle (3 peaks) the highest peak recorded 488, 322, 152 and 187 individuals/ 100 infested leaflets on broad bean, pea, fenugreek and snow thistle respectively. L. trifolii showed its highest monthly average numbers in February on Broad bean, Pea and, Fenugreek recording (383.25 ± 81.05, 256.75 ± 55.18 and, 101.5 ± 37.36 individuals / 100 infested leaflets) respectively and, (153.27 ± 27.10 individuals / 100 infested leaflets) for Snow thistle in April. On the other hand, the lowest monthly average numbers occurred in April on the four studied host plants recording (240.71 ± 113.11, 176.48 ± 59.22, 71.28 ± 24.05 and, 106.28 ± 47.73 individuals / 100 infested leaflets).