Examinando por Autor "Busuulwa, Allan"

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    Potential of mass trapping as a strategy for managing Diabrotica balteata (Coleoptera: Chrysomelidae) in beans (Phaseolus vulgaris L.).
    (Universidad EARTH, 2021-12) Busuulwa, Allan; Walter, Ndonkeu Tita
    The potential of mass trapping as a strategy for managing Diabrotica balteata (Coleoptera: Chrysomelidae) in beans (Phaseolus vulgaris L.) was evaluated as an alternative that can be integrated into insect pest management programs. An efficacy of control comparison was done between traps and two commonly used insecticides (contact and systematic). Initially, a laboratory bioassay was carried out to establish the efficacy of the two selected insecticides (REGENT® 20 SC and CONFIDOR 70 WG). Results from the laboratory assays indicated that CONFIDOR 70 WG was the most effective insecticide because it had the lowest Lethal dose (LD50) values of 0.75 µg/ml and LD90 of 40.0 µg/ml compared to those of REGENT® 20 SC, LD50 = 1.04 µg/ml and LD90 = 71.11 µg/ml. For the field study, a total of eight treatments including a control were formulated, based on doses recommended by the manufacturer (REGENT® 20 SC; 0.5, 0.6 and 0.7 kg/ha, CONFIDOR 70 WG; 0.17, 0.39 and 1.00 kg/ha) and traps baited with pheromones. Leaf defoliation was evaluated over a period of six weeks, and at the end of the growing season, dry weight of beans obtained from each treatment was evaluated. There were statistically significant differences (p < 0.05) between mean leaf defoliation of each treatment REGENT® 20 SC applied at a dosage 0.6 kg/ha had the lowest mean leaf defoliation value of 0.01 ± 0.002 while plots with the traps had the second highest mean leaf defoliation value of 0.05 ± 0.026. The control treatment had the highest mean leaf defoliation value of 0.07. The order of performance of the treatments from the treatment with the highest to the lowest leaf surface defoliation was Control > T1 > Traps > T2 > T3 > T4 > T6 > T5. There was a high correlation between leaf defoliation and dry weight of beans harvested. However, there were no statistical differences (p > 0.05) between the dry weight of beans in the various treatments. Treatment 5 (T5) had the lowest leaf defoliation value and illustrated the highest dry weight of beans of 0.18 ± 0.12 kg after harvesting which is equivalent to 236 kg of dry beans per hectare. Control had the lowest average yield with mean dry bean weight of 0.036 ± 0.03 kg, equivalent to 41.67 kg of dry beans per hectare. Various species of diabroticine beetles were observed in the field, these included Cerotoma ruficornis, Cerotoma atrofasciata and Omophita sp. Furthermore, traps were able to attract a variety of insect species ranging from insect pests of beans to important natural enemies. Insect pests captured were Diabrotica balteata and Agrosoma placetis, beneficial insects captured were stingless bees (Apidae: Meliponini), parasitoids (Hymenoptera: Braconidae), ladybugs (Coleoptera: Coccinellidae), parasitoids (Hymenoptera: Ichneumonidae), and spiders (Araneae: Clubionidae). Cost analysis revealed that control of D. balteata using REGENT® 20 SC was one of the most economical with a cost of USD 68 per hectare without taking into consideration other production costs.