Essays on the economic evaluation of integrated pest management extension in Nicaragua.

摘要

This dissertation assesses the economic impact of delivering integrated pest management (IPM) training through farmer field schools (FFS) in Nicaragua. The three essays are based on a cross sectional survey of 436 bean growers. The first essay presents evidence that prior experience with the environmental and health (E&H) effects of pesticides affect household decisions about pest management, but only when farmers are using toxic or highly toxic pesticides. When facing high health risks, farmers also tend to use protective strategies like hiring pesticide applicators.;The second essay evaluates FFS impacts on households' pest management, bean crop income and E&H outcomes. The E&H outcomes are represented by changes in the incidence of acute health symptoms and changes in the observed level of beneficial insects. One analytical complication is that FFS participants are not randomly selected from the population of farmers; they tend to be better managers on average. Results show that failing to correct econometrically for the endogeneity effects of this nonrandom selection associated with FFS participation can exaggerate the impacts of FFS. After correction for endogeneity this dissertation finds FFS performance to be inferior to other IPM training programs, at inducing IPM adoption, raising net income from beans and improving E&H outcomes.;The third essay explores the causes of poor FFS performance in Nicaragua by evaluating whether FFS impacts are influenced by the characteristics of the specific non-governmental organizations (NGOs) that implemented FFS. Two categories of NGO-specific effects make a difference, their institutional characteristics and the characteristics of their FFS on-farm research. Effective NGOs conducting successful FFS have many years of experience working with the targeted farmers, they have more extensionists, and most of their extensionists are trained in IPM (not necessary in FFS). When NGOs deviate from the original FFS focus on IPM training and shift the FFS focus to other institutional interests like promotion of credit programs, the FFS become less effective at disseminating IPM and improving farm benefits. Given the participatory research focus of FFS, the outcomes of on-farm FFS field experiments were also important. Farmers who observed higher yields or net incomes in the IPM plot compared with the conventional pest control plot were more likely to adopt IPM and reduce pesticide use. However, most comparisons between an IPM plot and a conventional plot resulted in lower yields and lower net revenues in the IPM plots.