Geographically, Kenya is a diverse country with many agro-ecological zones (AEZs). Maize (Zea mays L.) provides basic diet to millions of people in Kenya. Total land area under maize production is about 1.5 million hectares, with an annual average production estimated at 3.0 million metric tons, giving a national mean yield of 2 metric tons per hectare. Typically, yields range from 4 to 8 T/Ha in the high potential highlands of Kenya, representing only 50% (or less) of the genetic potentials of the hybrids. Highland maize varieties are grown on some 40-50% of the total maize area, representing 600,000 - 800,000 Ha. Constraints for maize production include drought, low soil fertility, pests and diseases. Foliar (leaf), stalk/ear rot diseases and stem-borers cause great losses in maize production in the humid transitional and high tropics of Kenya.