An overview of research on mechanisms of resistance in maize to spotted stem borer
1997
Kumar, H. (Agricultural Univ. (India))
The spotted stem borer Chilo partellus (Swinhoe) (Lepidoptera:Pyralidae) is an important pest of maize in several countries of Asia and Africa. Serious crop losses have been reported, mostly in experiments conducted under artificial infestations at experimental stations. In order to develop economical and environmentally friendly methods of pest management, a large number of maize genotypes with varying level of resistance to C. partellus have been identified. In the identified resistant germplasm, the three components of resistance, namely, non-preference, antibiosis, and tolerance, have been identified. In Asia, various studies have been conducted to elucidate the mechanism of resistance/ susceptibility in the two maize genotypes, Antigun Group 1 (Resistant) and Basi Local (Susceptible), against C. partellus. Several biological parameters including C. partellus larval and pupal survival, larval and pupal weights, larval and pupal period and fecundity were adversely affected due to unknown factors in the resistant source, but not on the susceptible one. An ethanolic extract of Mex 17 has also been reported to inhibit growth and development of C. partellus in comparison to the susceptible genotypes. The studies conducted in Africa show that ovipositional non preference by C. partellus on maize genotypes was due to trichomes and surface waxes. A genotype, ICZ-T, with trichomes on both the leaf surfaces was also developed. In some studies, using regression of grain yield reduction on foliar injury due to C. partellus attack on maize genotypes, namely, ICZ1-CM and ICZ2-CM, antibiosis and tolerance were reported to be the components of resistance. In more detailed studies in Africa, non- preference, antibiosis and tolerance types of resistance mechanisms have been reported to be operating within maize genotypes Mp704, Poza Rica7832 and ER - 29SVR.
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