Efficacy of insecticides from different chemical groups for control of soybean insect pests

Abstract

Soybean is the world’s most important vegetable oil crop with approximately 20% oil content and 40% protein. Soybean yields in Uganda have remained low over the years despite the increasing area under soybean production. This is attributed to several production constraints including damage due to field pests. Management of soybean pests has been majorly by use of chemical insecticides due to their immediate action on the target insect population. Many pesticides are available on the market; however, efficacy trials need to be conducted. The field experiment was conducted at Makerere University Agricultural Research Institute, Kabanyolo between April 2021 and July 2021 to evaluate the efficacy of pesticides from different chemical groups in control of insect pests of soybean and the variety Maksoy 3N was used. The experiment was set up in a randomized complete block design with five treatments including the Biopesticide (Azadirachtin 0.03%EC), Organophosphate (Dimethoate 40%EC), Aluminosilicate mineral (Kaolin WP), Neonicotinoid (Acetamiprid 20%SP), Carbamate (Methomyl) and the untreated control, each replicated three times. The results showed that all the tested insecticides had a significant effect (P<0.05) on all the pest parameters. Acetamiprid showed the highest efficacy against insect pests of soybean, followed by Dimethoate, Methomyl, Kaolin, Azadirachtin, and the control. Kaolin treated plots had the highest soybean biomass of 3333kg/ha followed by Acetamiprid and Azadirachtin treated plots (2963kg/ha). Kaolin and Azadirachtin recorded the highest soybean yield of 1556kg/ha. Soybean growth and development were considerably better in Acetamiprid treated plots. The neonicotinoid Acetamiprid seems to be a good option for insect pest management in soybean. Kaolin and Azadirachtin have the potential for increasing soybean yield. However, more research on the efficacy of other neonicotinoids available on the Ugandan market should be conducted.