Impact of Spillover Effects of Integrated Pest Management on Profitability of Non-mango Fruit Fly Infested Crops in Meru County, Kenya

The International Centre of Insect Physiology and Ecology (ICIPE) has recently developed and disseminated an integrated pest management (IPM) strategy for suppression of mango fruit flies among mango growing communities in Africa. Although the economic benefits of the fruit fly IPM strategy on the primary target crop (mango) are clearly demonstrated, the potential gains of the strategy on non- mango fruits hosts of the invasive fruit fly species in the same farm within which the IPM was introduced have not been quantified in the previous studies. These past studies failed to capture the widespread diffusion of the technology to other host cultivated plants which may essentially under estimate the actual impact of the fruit fly IPM on farm income. This study sought to examine the spillover effects of IPM strategy for suppression of mango fruit fly on profitability of other fruit crops. The focus was on four alternative cultivated hosts; namely, avocado, pawpaw, citrus and bananas of this major quarantine pest that are predominantly grown in Meru County, Kenya where the fly population has been observed to occur in large numbers. Using a semi-structured questionnaire, data were collected through a survey from 371 households and key informant interviews. Propensity score matching (PSM) using kernel based matching and radius matching were used to examine the indirect (spillover) impact of participating in IPM strategy on profitability of aforementioned enterprises. The results showed positive and significant cross-commodity spillover effect of the fruit fly IPM strategy on pawpaw and citrus. The strategy increased the average gross margins of citrus and pawpaw by approximately 27 percent and 38 percent per year per hectare respectively. Spillover effects were not observed for avocado and bananas at the farm level. The effort to disseminate IPM strategy would therefore yield more impact to farmers who cultivate a combination of mango, citrus and pawpaw in increasing their farm incomes.