Assessing the Impact of Weather Variables on Maruca vitrata (F) Population Dynamics in Green Gram and Evaluating the Efficacy of Various Insecticides

Abstract

The research was conducted during the Kharif 2018 season at the Central Research Farm, SHUATS, situated in Naini, Prayagraj. It encompassed two pivotal experiments aimed at understanding the population dynamics of the spotted pod borer and assessing the efficacy of various insecticides for its control. In the initial experiment, a 10×5m separate plot was designated to monitor the population dynamics of the spotted pod borer. Weekly observations were conducted by randomly selecting five plants and recording the larvae count per plant. Activity of the pest was observed from the 32nd to the 40th Standard Meteorological Week (SMW), peaking during the 37th SMW (9.88 larvae per five plants). Correlation analysis unveiled significant associations, including a positive correlation with rainfall (r = 0.789**) and a negative correlation with maximum and minimum temperature (r = -0.027NS and 0.260NS), as well as wind velocity (r = -0.465NS). In the subsequent experiment, the efficacy of various insecticides was evaluated using a randomized block design (RBD) with three replications and eight treatments, including an untreated plot. Two applications of all selected insecticide molecules were made against the green gram spotted pod borer, with data recorded before spraying, on the 3rd, 7th, and 14th days post-spraying. The results showcased the highest pest reduction in the chloropyriphos-treated plot (69.60%), followed by Cypermethrin (64.74%), Imidacloprid (53.04%), Quinalphos (47.26%), Monocrotophos (46.06%), Spinosad (40.96%), and Indoxacarb (34.93%) Notably, Indoxacarb (1:2.24) emerged as the most effective and economical treatment, followed by Spinosad 45SC (1:1.94), Monocrotophos (1:1.80), Chloropyriphos (1:1.75), Quinalphos (1:1.66), Imidaclopride (1:1.60), and Cypermethrin (1:1.59). This comprehensive study provides valuable insights into the management strategies for controlling the spotted pod borer in green gram cultivation, crucial for ensuring crop health and productivity.