Abstract:
Field trials were conducted at Kibaha and Morogoro in eastern Tanzania during two seasons
to evaluate the effect of nitrogen fertilization (0, 50, 75, 100 kg [N]/ha) on pest abundance, plant
damage and yield loss of maize due to stemborers. In general, ear and grain weights increased
linearly with nitrogen level. In the infested plot, grain weight increased 2.5 and 1.8 fold from 0 to
100 kg [N]/ha in the short and long rainy season, respectively, at Kibaha, and 1.4 and 1.6 times at
Morogoro. Yield loss decreased with an increase in nitrogen application and the effect was stronger
under high than low borer infestation levels. The results show the benefi cial effect of nitrogen on the
plant’s ability to compensate for borer damage. Analysis of economic benefi ts of applying fertilizer and
insecticide treatment indicated that using insecticides is not profi table under high-pest-low-soil fertility
conditions.
