Field experiments were conducted in Michigan, Minnesota, and Wisconsin to evaluate injurious interactions between nicosulfuron herbicide applied POST and nine insecticides applied at planting on ‘Pioneer 3751’ field corn in 1991. Insecticides were applied in-furrow, T-band, and surface band at planting. Corn injury from nicosulfuron and terbufos applications was more severe in Wisconsin than in Michigan. No corn injury was observed in Minnesota. Terbufos 15% ai granule (15G) or 20% ai controlled release granule (20CR) increased nicosulfuron injury to corn in Wisconsin. Nicosulfuron at 35 g ai/ha caused the greatest vigor reduction following terbufos 15G, intermediate vigor reduction following terbufos 20CR, phorate 20G, or phorate 20CR, and the least vigor reduction following fonofos, chlorpyrifos, chlorethoxyfos, tefluthrin, or carbofuran in Wisconsin.

Field and greenhouse experiments in 1981 and 1982 determined the potential interactions of three preemergence and three postemergence herbicides with four granular insecticides in soybeans [Glycine max (L.) Merr.]. Generally, metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one] increased soybean injury and lowered yields when applied to plots treated with an organophosphate insecticide at planting. Soybean injury from these treatments and from aldicarb [2-methyl-2-(methylthio)-propionaldehyde-o-(methylcarbamoyl)oxime] plus metribuzin applied in the field was greater in 1982 than 1981 due to excessive rainfall immediately after planting. Oryzalin (3,5-dinitro-N4,N4 -dipropylsulfanilamide) plus several of the in-furrow insecticide treatments in the greenhouse increased injury to soybeans. Other than this, the method of insecticide application, banded or in-furrow, had no effect on that caused by each pesticide combination.

Disulfoton and phorate applied in the seed furrow greatly reduce clomazone phytotoxicity to cotton in the field, whereas aldicarb does not. An experiment was conducted to determine the effect of aldicarb, disulfoton, and phorate on 14C-clomazone absorption, translocation, and metabolism by cotton grown in a sandy loam soil. Clomazone at 0.87 μg g−1 of soil alone or in combination with aldicarb at 0.6 μg g−1 of soil reduced cotton root and shoot growth 26 to 33%. Root and shoot growth were not reduced by clomazone plus disulfoton or phorate at 0.6 μg g−1 of soil. Protection of cotton against injury by clomazone was not explained by reduced absorption or translocation of clomazone or a metabolite to the shoot. Clomazone metabolism was reduced by disulfoton and phorate, thus indicating a clomazone metabolite may be more toxic to cotton.

A simple method for the insecticide bioassay of liposcelids is outlined. The contact toxicity of five organophosphorus insecticides (OPs) and two carbamate insecticides (CBMs) was ascertained for Liposcelis bostrychophila and L. entomophila. Liposcelis entomophila was more tolerant to all the insecticides tested than the other species. Malathion was the least toxic OPs to both species, while chlorpyrifos-methyl was the most toxic insecticide tested against L. bostrychophila. These findings are discussed in relation to the infestation of these liposcelids in rice storages.