The efficacy of neem (A. indica A. Juss.) seed products for the control of the spottedrnstem borer, Chilo partelilis (Swinhoe) on H51l, ICZ3, ACV3, and Katumani maizerncultivars was investigated in two geographical locations. Maize plants were eitherrnartificially infested with blackhead stage egg batches of C. partel/lIs, .01' were initiallyrnleft unprotected for natnral infestation to take place before application of treatments.rnNeem seed powder (NSP) (3 g/plant), neem seed powder-sawdust mixtnre (NSP*SD) (6rng/plant), or 10 % aqueous neem seed extract (NSE) (500l/ha) were applied at fourrnweeks after crop emergence (W AE) with untreated controls. Dipterex (D PTX) (lrng/plant), or Sevin (500l/ha) were also used for comparison. Maize plants treated withrnneem seed products or chemical insecticides sustained much less borer holes, reducedrnleaf damage and stem tunneling than those in the controls in all the test cultivarsrn(P < 0.001). NSP provided comparable and effective protection ill par with Dipterex orrnSevin. NSP*SD and 10% NSE also showed more or less similar and appreciable effectsrnin reducing leaf damage and stem tunneling by C. partelilis larvae. Foliar applicationsrnof neem seed products and chemical insecticides effectively suppressed the densities ofrnC. partelills and subsequently improved the yield in all the test cultivars (P < 0.05).rnFoliar applications of neem seed products level to chemical insecticides in markedlyrnreducing primary crop damages, in effectively suppressing the level of infestation by C.rnpartelllls, and in improving yield in all the test cultivars. The findings unequivocallyrndemonstrated that applications of neem seed products effectively control C. partellllsrnand avert serious crop damages and yield loss in field sitnations.rnIn the laboratory, neonate C. panelills larvae were reared on artificial diet containingrnminute quantities of NSP (25, 50 or 100 ppm), 10% NSE (25, 50, or 100 ppm), orrnneem bitter concentrate (NBC) (5, 10, or 25 ppm). Artificial diet without neem seedrnproducts served as controls. Larvae were introduced singly into the cultnre vialsrncontaining 10 ml of artificial diet incorporating the treatment types and were eitherrnmaintained on the same diet or transferred to standard diet two weeks after inoculation.rnPer cent larval survival, pupal weight, per cent pupation and emergence as an adultrnwere examined and recorded. The duration of the developmental stages and totalrndevelopment periods were studied. Larval growth index (LGI) and Adult growth indexrn(AGI) values were also determined. NSP (100 ppm) significantly reduced survival ofrnlarvae to the pupal stage and to adult emergence as compared to the other treatmentrntypes (P