The most important field pests of common beans is bean flies. There is interaction of bean fly with root rot and Fusarium wilt disease complex in soils with depleted nutrients causing yield loss. Alternative management strategies were evaluated in Kenya in regions with severe decline in soil fertility to optimize yields. There was variation in bean fly infestation and damage in the cultivars and fertilizer rates during different seasons and locations. Plant resistance and response to fertilizer were influenced by environmental conditions, location specific and season. Phosphorus fertilizer increased growth and grain yield but didn’t reduce infestation and plant damage, while Organic manure did. Efficiency in P- Acquisition was determined to be important in plant tolerance to bean fly . Cultivar selection is important factor in developing IPM strategy for bean fly control. Resistant varieties have morphological, physiological or biochemical factors that when combined with soil fertility amendments are effective in control. This book is recommended for research scientist, agricultural extension service providers, and university and middle level agricultural college students.