Effects of Insecticide-Herbicide Interactions on Soybean Plants Grown on Eight Louisiana Soils.

In 1979, a study was initiated to determine if selected rates of aldicarb(2-methyl-2(methylthio)propionaldehyde O-(methylcarbamoyl oxime), trifluralin (a,a,a-Trifluoro-2, 6-dinitro-N, N-dipropyl-p-toluidine) and metribuzin (4-amino-6-(1, 1-dimethylethyl)-3-(methylthio)-1, 2, 4-triazin-5(4H)-one), applied alone and in combination, resulted in phytotoxic reactions in soybeans, Glycine max (L.) Merr. var. Davis. The three greenhouse studies and one field-greenhouse study were conducted on eight selected Louisiana soils to determine to what extent the soil characteristics affected the biological activity of these combinations. The trifluralin-containing treatments used in this study, generally, produced stunted, thick-stemmed plants with smaller and fewer nodules than the non-treated check plants. However, N(,2) C(,2) H(,2) activity was significantly reduced in only 1.5% of the total observations made, a clear indication of the soybean plant\u27s ability to overcome adverse conditions. The addition of metribuzin and/or aldicarb to trifluralin-containing treatments did not substantially increase the detrimental effects above those demonstrated by the trifluralin alone. Applied alone, metribuzin and aldicarb produced very few adverse effects. The wide array of soils utilized in this study appeared to have little effect on the biological activities of these pesticide compounds. The insect and arthropod populations monitored in this study varied in their susceptibility to aldicarb