Efficacy of <em>Psidium guajava</em> (L.) Leaves Extract Against <em>Spodoptera frugiperda</em> J.E. Smith (Lepidoptera: Noctuidae) Larvae

Purpose: Fall armyworm (FAW) Spodoptera frugiperda J.E Smith is an invasive pest of maize crops that has been recently reported in Pakistan (2019). Synthetic insecticides are the main choice of local farmers to control this deadly pest, but with continuous use of these pesticides health and environmental issues have arisen, which demands an alternative control measure. Considering this pest’s significance, this study was conducted to determine the potentiality of Guava (Psidium guajava L.) against the third instar larvae of S. frugiperda; which is considered an effective repellent effect.Research Method: The P. guajava leaves were extracted with methanol, ethyl acetate, n-hexane, and chloroform; each extract was prepared at different concentrations of 125, 250, 500, and 1000 ppm. Later, the larval mortality was recorded at different intervals of 24, 48, 72, and 96 hrs, and antifeedant activity at 24 hrs.Findings: The highest mortality of 92.86% was observed on methanol extract at 1000ppm after 96 hrs. The mortality on all crude extracts and at every concentration increased at different intervals of the observation and reached the maximum at 96 hrs. However, the LC50 and LC90 values of 154.77 and 865.3ppm after 96 hrs were recorded in methanol. Similarly, the highest antifeedant activity was 87.5% recorded in methanol at 1000ppm, and the lowest antifeedant activity of 22.58% was noted in chloroform extracts at 125ppm concentration. It showed that the antifeedant activity relied on a concentrated dose; meanwhile, the P. guajava with methanol crude extracts successfully stopped the feeding activity of S. frugiperda.Originality/ Value: Therefore, based on the obtained results, the P. guajava leaf extracts are highly recommended, particularly for their extraction with methanol and n-hexane which showed the highest larval mortality and antifeedant activity of S. frugiperda.