Preferred Stage Of The Crop For Cotton Stem Weevil Infestation And Scanning Electron Microscopic View Of Healthy And Infested Cotton Stem

Abstract

Cotton stem weevil, Pempherulus affinis Faust is the most destructive pest of the seedling stage of cotton in South India. Its habitat, inside the stem protects the pest from control measures and hence management of this pest is challenging. The pest occurred in the early stage of the crop, multiplied later, and continue the damage in grown-up crop until dislodging of galled plant and carry over to next season’s crop. Hence, the present study was carried out to identify and to generate information about the preferred stage of the crop for cotton stem weevil infestation to recommend timely management tactics as heavy yield loss occurs due to early infestation. Four staggered pot culture sowings at weekly intervals were done to attain four phonological stages of the crop viz.,15 Days After Sowing (DAS), 22 DAS, 29 DAS, and 36 DAS. Five pairs of weevils were released at each stage of the crop and the observation was made on the infestation level on different days after the release of the weevil. The mean percent infestation at different growth stages of the crop revealed that the highest percent infestation was found in fifteen days old crop (63.57). The present study revealed that the early stage (15 days old crop) are more prone to stem weevil infestation than compared to later stage.The contribution of this study is that the management tactics are advised to practice in early stage of the crop to reduce stem weevil infestation and to prevent yield loss.