Maize cob rot in Kenya and its association with stalk borer damage

Cob rots are a major cause of crop loss in areas such as western Kenya that experience-prolonged rainfall during the period of crop maturation. Cob ro t fungi cause spoilage of the grain and some of them produce mycotoxins whi ch can pose a health risk to humans and animals consuming foods prepared fr om contaminated grain. Surveys conducted in western Kenya in 1998 showed th at cob rot incidence exceeded 20%. In the following year when rainfall was greater around the harvest period, cob rot fungi affected 68% of cobs. In 1 998 stalk borer larvae (mainly Busseola fusca) damaged 12% of cobs and ther e was a strong correlation (R = 0.87) between cob rot incidence and borer d amage. In 1999 almost half of the cobs sampled showed evidence of borer dam age. The results indicate that the high cob rot incidence in this part of w estern Kenya is due to stalk borer damage, which predisposes the cobs to fu ngal infection, and that management of the borer would greatly decrease cob rot incidence. (C) 2000 Elsevier Science Ltd. All rights reserved.