Efficacy of ezoate 57ec containing emamactin benzoate on level of infestation of fall army worm on longe 10h maize variety in Uganda

Abstract

Fall army worm, FAW, is an insect pest native to tropical and subtropical regions of Americas. It is new to Africa and was first detected in central and West Africa in early 2016 and was reported in Uganda in June 2016 in the districts of Kayunga, Kasese, and Bukedea. By the end of 2017, the pest had spread to all the districts of Uganda. FAW is a migratory, and highly polyphagous pest capable of feeding on more than 80 plant species with cereals (maize and sorghum) being the most preferred hosts. The purpose of this study was to evaluate the efficacy of Emamectin benzoate (Ezoate 57EC) as a control measure against FAW on long10H Maize variety. Two field trials were conducted in two seasons of 2021B and 2022A at NaSARRI. Four concentrations levels of emamectin benzoate were used (11.3 ml, 9.4 ml, 4.5 ml and 3.4 ml) including 25ml of rocket used as a positive control and no spray used as a negative control. The chemicals were mixed in 15L of water. A completely randomised block design (RCBD) was used to set up the experiments with three replicates. Spraying was done once and data for FAW incidence, cob damage, yield and unshelled maize weight were collected before and after spray. Yield data collected was also used in computation of yield loss. The results obtained showed a significantly (<.001) high variation in the efficacy of different concentration of emamectin benzoate against the FAW in both seasons. The 11.3 ml concentration was superior to the rest of concentrations as it caused 90% percentage reduction in mean FAW incidence, lower mean percentage cob damage 3.69% and 6.04%, higher mean yield 6533.33Kg/H, 5866.67kg/H in both seasons, respectively. This is followed by 9.4ml of emamectin benzoate and 25ml of rocket that had no statistical difference in performance across all parameters studied in the two seasons. The 4.5ml and 3.4ml of emamectin benzoate were lower and had no statistical difference in performance across all parameters assessed in the two seasons. The plots were not sprayed had the worst performance in all parameters studied, low yield 1800.00kg/h and 1755.56kg/h were obtained in the respective seasons. It was observed that all concentration of emamectin benzoate had an effect on the FAW incidence, yield and cob damage, however spraying maize with concentration of emamectin benzoate varying between 9.4 ml and 11.5 ml per 15L of water is recommended. However, further research should be done to evaluate the effect of Emamectin benzoate against beneficial insects like bees, butterflies.