Abstract
Studies on sorghum tolerance of the stem borer, Chilo partellus Swinhoe, based on plant variety and time of attack were carried out under field conditions. More tillers were produced by the infested plants, with the plants infested two weeks after germination producing the most. The varieties differed significantly in their production of secondary tillers, with Serena, LC119/80-2 and PIO/I producing the most. In general, tillers from infested plants produced fewer panicles and had higher proportions of juvenile panicles. Plants infested two weeks after germination were the least effective and had higher proportions of juvenile panicles. Varieties did not differ significantly in their proportions of effective tillers and juvenile panicles; yield components were slightly reduced in the infested plants in all varieties, particularly those infested 2-4 weeks after germination, except in LCl19/80-3 where there were yield gains. There were direct relationships between yield and leaf damage in local Olusi and PIO/I varieties and also between yield and deadheart production in Serena and NES7360.
