Assessment of Yield Loss of Sorghum and Pearl Millet due to Stem Borer Damage

Abstract

The stem borer species that infest sorghum and pearl millet are listed. At ICRISAT Center in India, loss in grain yield due to Chilo partellus damage in sorghum was estimated by two methods. These experiments involving the phased use of carbofuran, or artificial infestation using laboratory-reared first instar larvae showed that maximum grain yield loss occurred when infestation took place 15-30 days after crop emergence. The maximum number of deadhearts was formed when infestation took place during this period. Stem tunneling caused by later infestations did not cause a reduction in grain yield. In two studies at the ICRISAT Sahelian Center in Niger, results showed that under low levels of borer infestation (caused by Coniesta ignefusalis), a nonprotected pearl millet crop gave slightly higher yields than one that was protected by insecticide. In a date of sowing trial, losses were heavier on late-sown millet with an increase in proportion of nonproductive tillers. Yield loss caused by other borer species are also discussed