Field Efficacy of Azadirachtin, Chlorfenapyr, and Bacillus thuringensis against Spodoptera exigua (Lepidoptera: Noctuidae) on Sugar Beet Crop

Abstract

 Spodoptera exigua (Hübner) is a highly dispersive and polyphagous species that can be a serious pest of vegetables such as sugar beet. Field experiments were conducted to evaluate the efficacy of azadirachtin, chlorfenapyr, and Bacillus thuringensis (Bt) against the pest population and its quantitative and qualitative damages on sugar beet during the cropping season 2014/2015 in Lorestan province, west of Iran. Samplings for estimation of S. exiguae densities were conducted 1 day before (DBT) treatment and 1, 3, 5, 7, and 10 days after treatment (DAT). Finally, total yield and sugar content of sugar beet in each treatment were recorded. Results showed that one day after treatment (DAT), chlorfenapyr significantly decreased the pest eggs and larvae densities, but azadirachtin and Bt did not significantly reduce the egg population. Similar performance of azadirachtin and Bt to reduce the larval population occurred with delayed effects at 5 and 7 DAT, respectively. Lastly, the result of yield and sugar value of sugar beet showed that azadirachtin was the most effective for controlling S. exigua population.