The relationship between sowing date and the maize stalk borer,Busseola fusca(Fuller) in terms of infestation rate, and crop damage was studied using ten successive sowing dates between April and July in 1985 and 1986. Different degrees of infestation byB. fuscawere recorded from all sowing dates. Early sowing in April and the early part of May had significantly lower infestations of first generation larvae. Levels of infestation by second generation larvae were significantly higher on late sowing dates. High infestation by second generation larvae appeared to be connected with the high biotic potential of the moths of the first, non‐diapause generation. Second generation larvae caused crop loss ranging from 22–5 to 100% while it was only 0–22.6% due to the first generation. In conclusion, delay of sowing later than April may result in serious crop yield loss due to the second generation larvae ofB. fuscain Awassa.