Impact of spatio-temporal simulations of rat damage on yield of rice (Oryza sativa L.) and implications for rodent pest management

Abstract

Rodents often damage crops throughout the growing season, from germination to harvest, thus making it difficult to understand the cumulative effects of rodent damage for crops such as rice that are able to partially compensate for damage. Compensation can make it difficult to understand the impact of variable rodent damage in terms of when the damage occurs, its severity and thus when, whether and how rodent pests should be controlled. The compensatory responses of rice to simulated rat damage carried out at different growth stages and at different spatial levels of severity showed that higher yield was recorded during the wet season in comparison to the dry season. However, yield loss was observed during all cropping stages for all levels of simulated damage for wet and dry season crops, with significant compensation noted at the transplanting [14 days after sowing (DAS)] and vegetative (45 DAS) stages. Only damage at the maturity (110 DAS) stage resulted in significant reductions in rice crop yield. Seasonal differences suggest water availability was an important factor that perhaps enhanced rice production. The ability of rice to compensate for early rodent damage could potentially reduce a farmer’s perception of damage. However, failing to control rodents at these earlier crop growth stages could lead to increased rodent populations at the time of maturity when compensatory effects are limited.