Life cycle of Thrips palmi (Thysanoptera: Thripidae) and host plant registered in the Cauca Valley

Abstract

In 1997, the presence of Thrips palmi was detected in watermelon in Roldanillo (Va­lle del Cauca, Colombia) and in cucumber in El Cerrito (also in Valle del Cauca). A survey was conducted of host plants of this polyphagous pest, and growth parameters of the insect were determined in several vegetable crops. Visits were made to vegetable cropping zones of Va­lle, located at different thermic levels, and samples of host plants with the insect were collected. Teachers and students of the Universidad Nacional de Colombia-Sede Palmira, identified the specimens. Samples were also sent to the taxonomist L. Mound (Britsh Museum, Londres) for confirmation. The biological studies of the insect were conducted under lab conditions (25 ± 5 °C, 70 ± 5 % RH) using green pepper, cucumber, eggplant, and tropical squash. First instar larvae were placed in plastic jars until they became adults. T palmi was found in 20 districts located between 800 and 2500 m.a.s.1., feeding on vegetables, especially lulo, eggplant, green pepper, tomato, tropical squash, watermelon, cucumber, and green beans. Development time from egg to adult was 14.8, 13.0, 11.4 days in eggplant, cucumber, green pepper, and tropical squash, respectively. Females were particularly fertile in eggplant (22.8 eggs/ female) and less fertile in green pepper (12.2 eggs/female). Parameter R. was 8.7, 8.5, 7.1, and 10.7, and parameter R. was 29.3, 35.0, 25.4, and 34.4 in eggplant, cucumber, green pepper, and tropical squash, respectively. The most common na­tural enemies were the following predators: Orius spp. (Hemiptera: Anthocoridae); Amblyseius spp. (Acari: Phytoseiidae), different species the Coccinellidae (Coleoptera) y Franklinotrips sp. (Thysanoptera: Aeolothripidae).