The impact of granular formulations of phorate, terbufos, carbofuran, carbosulfan and thiofanox on newly sown Italian ryegrass (Lolium multiflorum)

The effect of applying granular formulations of phorate, terbufos and carbofuran to grass at the time of sowing at a range of dose rates ‘in furrow’ (i.e. drilled with the seed down the coulter tube into the drill row) or broadcast was assessed at two sites in each of two years. The effects of carbosulfan and thiofanox were assessed at one site in one year. All of the chemicals except thiofanox enhanced yield in one or more experiments by a sufficient amount to be economically viable. Much of the yield benefit seemed to derive from the control of frit fly larvae. Earthworms are an important component of the grassland fauna and checks were made of the effects of the chemical on their numbers. Their populations were affected initially in some experiments by phorate, terbufos and carbofuran, but their numbers recovered subsequently. There was a trend for treatments made ‘in-furrow’ to make more economic use of the pesticides compared with broadcasting them.