Status of the flat grass scale, Aclerda takahashii Kuwana (Hemiptera: Aclerdidae) and morphological characters associated with resistance in wild sugarcane (Saccharum spontaneum L.)

Abstract

Status of the flat grass scale, Aclerda takahashii Kuwana (Hemiptera: Aclerdidae) and the morphological characters associated with resistance in the international collection of S. spontaneum maintained as a part of world sugarcane germplasm at the ICAR-Sugarcane Breeding Institute-Research Centre(SBI-RC), Kannur, Kerala was examined. The scale appeared in May coinciding with cane formation and the infestation increased during the post-monsoon period which continued until harvest. They were noticed in both internodal and nodal regions of the entire sugarcane stalks hidden inside the leaf sheath. The 79 accessions were grouped into three categories on the basis of infestation rate in which 62 were found to be least susceptible, 15 were moderately susceptible and 2 accessions were found as highly susceptible. In the least susceptible category, 27 accessions constituting about 34% of the total accessions were found to be totally free from the Aclerda takahashii attack under field condition. The highest infestation was recorded in the accession Djantoer 1. Non-parametric analysis of infestation parameters indicated that the accessions having different origin showed significant difference with respect to infestation rate and percent intensity. The highest and lowest infestation rate was recorded in Japan collections and US collections, respectively. Among quantitative stalk characteristics, leaf sheath length was found to be a significant morphological feature associated with infestation rate with positive correlation.