Numerous studies have been carried out on pesticide handling practices in agriculture, but drivers of farmers' intentions to use pesticides are not well documented. The main purpose of this study was to explore farmers' intention to use pesticides in agriculture, based on an expanded version of the theory of planned behavior (TPB), with knowledge about pesticides and moral norms as additional constructs in the original TPB model. A sample of 400 cereal farmers of irrigated farmlands of Moghan plain, Iran was selected using multistage cluster sampling. Knowledge about pesticides hazards was the most important variable affecting farmers' intention to use pesticides. Knowledge mainly impacted perceived behavioral control of pesticide use and attitude towards pesticides. Thus, high levels of knowledge about pesticides were linked with greater influence of attitudes towards pesticides on farmers' intention. In turn, perceived behavioral control of pesticide use was affected by moral norms, subjective norms, and attitudes towards pesticide use. Moral norms and subjective norms also affected attitudes towards pesticides. Findings offer new evidence on the interrelationship of several variables in forming farmers' intention to use pesticides in the context of the widely used model of the TPB, for which no data are available in the literature. Promoting knowledge about pesticides is a fundamental step for regulating pesticide use among farmers, probably by stabilizing and rendering farmers' attitudes resistant to change. Moral norms and subjective norms can play a role mainly by affecting perceived behavioral control and attitudes towards pesticides. Combination of educational interventions for upgrading general knowledge about pesticides, with training courses, disincentives, and public awareness campaigns relating to pesticides may improve our ability to affect farmers' behavior.
