Assessment of organophosphate insecticide application practices among smallholder tomato growers in central Kenya

Abstract:

Organophosphate insecticides remain the dominant pest control measure among tomato growers in sub-Saharan Africa, yet comprehensive data on their application practices at the smallholder level are limited. This research investigated the insecticide usage patterns, application frequency, protective behavior, and information sources among 240 smallholder tomato farmers across three sub-counties in central Kenya during the 2025-2026 growing seasons. A structured questionnaire complemented by field observations was employed to collect primary data. Descriptive statistics, chi-square tests, and Pearson correlation analysis were applied. The results revealed that organophosphates constituted the most widely used insecticide category (38.4%), followed by pyrethroids (27.6%) and carbamates (18.2%). Agrochemical dealers served as the primary source of pest management information for 34.2% of respondents, while only 19.5% consulted government extension officers. A moderate positive correlation (r = 0.61, p<0.01) was observed between farming experience and spray frequency per season. Personal protective equipment usage was inadequate, with only 12.7% of farmers wearing goggles during application. The findings demonstrate that insecticide selection among smallholder tomato growers in central Kenya is predominantly influenced by product availability and dealer recommendations rather than technical suitability, underscoring the need for targeted extension services and farmer education programs.