RODENTS AS AGRICULTURAL PESTS IN MEXICO—NATIONAL RODENT CAMPAIGN

Since 1973, through the Ministry of Agriculture and Water Resources, the Mexican Government has established a general campaign against the most important groups of vertebrate pests, which cause severe damage to growing crops, stored products and mechanical damage to agricultural and irrigation schemes. To achieve information on this subject, presently the main office of the program is engaged on several activities such as the evaluation of the damage, trapping, species involved, research on population structure (densities and fluctuations to prevent sudden increase of rodent population), sex proportion, pregnancy (number of embryos), bait formulation, distribution methods, etc. Sigmodon spp., Oryzomys spp., Peromyscus sp., Rattus spp., Mus sp., Microtus spp. and several members of the Geomyidae have been found to be of a great importance under field conditions