Protection of stored plant products from rodent pests using chlorophacinone

Abstract

Apart from some preventive measures, advisably taken during construction of storage facilities or at the time of product storage, treatments with chemical rodenticides have been the most widely practiced method of controlling commensal rodents. Their control in storages is normally carried out after animal presence has been observed, and treatments from early autumn onwards, throughout the season, provide the best effect. The paper shows the effects of baits with lower content of the active ingredient chlorophacinone than recommended for protecting stored plant products from rodents. The experiments were set up using the relevant OEPP/EPPO method. Different contents (0.005% and 0.0075%) of the active ingredient chlorophacinone were used in a ready for use (RB) paste bait formulation. Baits were laid in boxes along rodent routes, underneath pallets with sacks and in places where major damage was observed. Baits for house mice were placed at a rate of 10-20 g per 1-3 m, while 30-50 g of baits for brown rats were laid at specific points. Daily bait intake was monitored over a period of 10 d and the portions were replaced with new ones as needed. Placebo baits were laid in identical boxes for 4 d before the experiment began. The abundance of house mice was estimated based on the highest and lowest daily intake of bait divided by the species’ daily food requirement. The data in this experiment show that 0.005% and 0.0075% chorophacinone contents in RB baits changed neither palatability nor bait efficacy in controlling house mouse and brown rat indoors. The average efficacy of chorophacinone was 87-93% against house mouse and 90-100% against brown rat.

Keywords: Chlorophacinone, Rodent, Storage, Efficacy