MAIZE (ZEA-MAYS L) STEM BORER (CHILO-PARTELLUS SWINHOE) INFESTATION DAMAGE AND PLANT-RESISTANCE

Resistance/susceptibility of maize to the spotted stem borer attack is ascribed to a number of damage parameters but the effect of these in causing yield loss is not fully understood. The objective of this study was to determine the effect of artificial infestation on yield loss and if possible, to identify the most useful damage parameter in selecting for breeding purposes. Results obtained reveal that the overall effect of infestation is a general reduction in vigor exemplified by delay in flowering and reduction in height, number of ears harvested, length of ear and consequently, grain yield. The degree of damage caused was not commensurate with the yield loss however thus suggesting that breeding for tolerance rather than resistance per se would be more desirable. However, appropriate criteria to measure tolerance is required. Furthermore, the addition of the foliar lesion parameter, a visual damage trait would be useful in appreciating the presence of resistance.