Developing the research and education components for an integrated pest management program for sweet onions in Honduras

My thesis focuses on finding workable solutions to farmers' production constraints in Integrated Pest Management (IPM) for sweet onions ( Allium cepa) in Honduras. First, I researched the biological and economic components of onion thrips (Thrips tabaci) management. The use of action thresholds (AT) as a decision tool for timing insecticide applications is better than the grower's standard practice of calendar applications. Onions grown under favorable climatic conditions with thrips infestations under 1 thrips per leaf per day do not affect yield. The AT range for the dry season is between 0.5 and 1.6 thrips per leaf (TL). The analysis indicated that with the 1.6 AT farmers will get back their investment in control cost, however, with the 0.5 AT farmers will maximize their investment in thrips control. Experiments were conducted to develop a Thrips Insecticide Bioassay System know as 'TIBS.' In this bioassay, thrips are collected directly from the onion plants in the field into the bioassay vials coated with an insecticide. TIBS is sensitive enough to detect differences in susceptibility to different insecticides, thrips life stages and periods of the onion growing season. Data collected suggest that there are not serious problems with thrips insecticide-resistance in the main onion growing regions of Honduras and Nicaragua, with the possible exception of cypermethrin in Nicaragua.;The second component of my work was an IPM extension effort to develop and refine the control practices for sweet onion pest problems. The technical results of the IPM extension efforts are summarized in the Sweet Onion IPM Manual which should be considered an Integrated Crop Management (ICM) manual. "Non-traditional" IPM topics were incorporated in the manual because they relate in a direct or indirect manner to the control or prevention of pest problems. The last component of this thesis is a chapter that traces the evolving definition of IPM, examines some differences between IPM programs in large- and small-scale farming, and assesses the role of farmers and the larger society in shaping IPM programs. Implications of these evolutionary changes from an educational perspective are also examined.