The response of Meriones shawi to seven rodenticides was investigated in laboratory feeding tests. The species proved to be much less susceptible to anticoagulants than most other species of rodent pests. Brodifacoum (at 0·005%), although giving complete mortality after only 8 days' continuous feeding, was more toxic than warfarin (0·025%), coumatetralyl (0·0375%), difenacoum (0·005%) and bromadiolone (0·005%). Calciferol (0·1%), though toxic, was significantly unpalatable. Zinc phosphide (5·0%) presented for 2 days in a choice test against unpoisoned food gave 80% mortality and appears to be the most suitable of these compounds for the control of M. shawi in the field.

A single application of the male chemosterilant, α-chlorhydrin, to a problem sewer rat infestation resulted in reductions of rat numbers and distribution which was comparable to effects of warfarin baiting methods. Rat numbers were reduced by more than 85% by both methods. More rapid mortality and recruitment were evident for warfarin effects; the α-chlorhydrin treated population had a longer lag phase of growth so that reinfestation of sewer habitat to pre-treatment numbers, and distribution over a 40 square block area, required approximately 1·5–2 times longer after α-chlorhydrin treatment when compared with warfarin treatment. Comparisons of changes in rat densities in infested sewers following the two treatments indicate that recovery of warfarin treated populations is achieved by reproductive recruitment followed by dispersal while α-chlorhydrin treated populations recover by slower immigration and later reproductive recruitment. Alpha-chlorohydrin should be a useful addition to a limited arsenal of rat control agents because of its specificity for the Norway rat, its single dose effectiveness as a toxicant-chemosterilant, and its short environmental half-life.