Field Efficacy of Synthetic and Botanical-Derived Insecticides Against Melanaphis sacchari1, and Non-Target and Beneficial Species Associated with Cultivated Sorghum

Abstract

The purpose of the study was to investigate the field efficacy of commercial insecticides against Melanaphis sacchari (Zehntner) and determine the diversity of non-target species associated before and after treatment. Treatments were applied at 35 and 50 days after germination, and associated insects were sampled with yellow traps 48 hours after application of each product. Insect abundance differed significantly from the control that had 1,006 and 3,750 aphids on the first and second days of evaluation, with fewer aphids at the first sampling (35 days). The most effective products were flupyradifurone (Sivanto®), imidacloprid (Uniprid®), acephate (Unifate®), and Chenopodium ambrosioides botanical extract (Requiem®), with efficacies of 99.95% (0.5 aphids/plant), 99.05 (9.5 aphids/plant), 99.41% (6.0 aphids/plant), and 76.78% (233.5 aphids/plant) (Fn,3 = 19.78; df = 5,12; p < 0.001, r2 = 0.8918), respectively. At the second sampling (50 days), efficacy of flupyradifurone was 100%, and Ch. ambrosioides plant-derived product and spinetoram (Palgus®) were opposite (Fn,3 = 43.14; df = 5,12; p < 0.001, r2 = 0.9473). We collected 980 insects associated with sorghum, in five orders, 26 families, and 53 species of Coleoptera, Diptera, Hemiptera, Hymenoptera, and Neuroptera. Species richness increased as abundance decreased. Species richness and abundance were greatest at the first assessment. The Shannon-Wiener diversity index was between 1.2 and 1.6 for the first assessment and 1.8 and 2.4 for the second evaluation. Flupyradifurone, imidacloprid and acephate should be included in integrated management of M. sacchari, considering adequate use of the product.