Tailor-made solutions to tackle rodent pests of rice through community-based management approaches in Cambodia

Abstract

Rodents are a major pest of rice throughout Southeast Asia, causing both pre- and post-harvest losses. In Cambodia, where 90% of the cultivated land is used for rice production, rodent damage to rice can cause significant impacts to smallholder farmers’ livelihoods and to food security. To help smallholder farmers minimize yield losses from rodent pests, adaptive research experiments were established in two villages in Takeo province. In each village, three replicate 5-ha sites were selected for treatment and three for control. In each treatment site, groups of farmers implemented ecologically-based rodent management (EBRM) methods over two rice cropping seasons. The management methods were adapted based on the local situation and preferred practices of farmers and included maintaining basic hygiene in field margins, synchronous planting of rice crops, community rat hunts, no electric fencing and the implementation of a Community Trap Barrier System (CTBS) along with a Linear Trap Barrier System (LTBS) in an area of intensive rice monoculture, and a LTBS with targeted and limited bromadiolone rodenticide in an area growing recession rice on lake margins. Over 130 rats were caught at each treatment site per season and rodent damage levels were reduced from a mean of 22–34% per site and season in the non-treatment sites to less than 6% in the treatment sites. Following the implementation of EBRM, rice yields were, on average, 20–32% higher in the treatment sites than in the non-treatment sites, giving a 53–169% increase in net income and a benefit-cost ratio ranging from 3:1 to 11:1 per season. We show that rodent damage to rice in Cambodia and the associated yield loss can be significantly reduced following the implementation of cost-efficient EBRM approaches that were locally adapted to village-specific agro-ecological and social conditions. We conclude by discussing incentives that support the adoption of these practices by smallholder farming communities.