An experiment was conducted during 1990 and 1991 in Kenya, to study the reaction of 27 sorghum genotypes to stem borer Chilo partellus damage under irrigated and drought conditions. Crop growth was maintained at irrigated and water-stressed (non-irrigated) conditions. Data were recorded on deadheart formation due to stem borer, leaf area damaged, number of larvae per 5 plants, peduncle damage, and recovery resistance under natural infestation. Analysis of variance indicated significant differences due to genotype, irrigation treatments and genotype x irrigation treatment interaction in plants with deadhearts, number of larvae, leaf feeding, peduncle damage and recovery resistance for genotypes, except in case of leaf area damage. Deadheart incidence was slightly lower (70.4%) in irrigated than non-irrigated plots. Leaf feeding was greater (94.7%) under irrigated than non-irrigated plots (91.5%), except in the case of genotypes (ICSV 88013, IS 8193, KAT 83368, IS 23509 and ICSV 112). Peduncle damage was lower (5.8) under irrigated than non-irrigated conditions. Plant recovery in response to stem borer damage was greater under irrigated (5.4) than non-irrigated (6.3) conditions, except for ICSH 89020, IS 23509 and ICSV-CM 865132. The number of stem borer larvae were greater (41.8 larvae per 5 plants) in irrigated than non-irrigated (27.3 larvae per 5 plants) plots. Irrigation reduced deadheart incidence, peduncle damage, and recovery resistance in sorghum due to stem borer infestation
