Effect of Fungicides, Herbicides and Combinations on Root Growth of Cotton1

Abstract

AbstractWe studied the effect of soil‐applied herbicides and fungicides on cotton (Gossypium hirsutum L.) root growth under ambient greenhouse conditions. Root growth of cotton was not affected by soil treatment with the fungicides 1‐Chloro‐2‐Nitropropane (Lanstan)3 or Pentachloronitrobenzen+ e 5‐Ethoxy‐3‐trichloromethyl‐l‐l‐l,2,4‐thiadiazole (Terraclor Super X)3. Trifluralin (α,α,α, trifluoro‐ 2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) applied at 0.84 kg/ha did not affect cotton roots when applied preplant and incorporated; however, the higher rate (1.68 kg/ha) significantly reduced total root growth. Fluometuron [l,l‐dimethyl‐3‐(α,α,α,‐trifluoro‐m‐tolyl)urea] was not injurious to cotton at the rate evaluated. Root growth of cotton was significantly reduced by treatment with 3.36 kg/ha of prometryne [2‐4‐bis(isopropylamino)‐6‐(methylthio)‐s‐triazine] applied as a preemergence spray. There were no significant interactions between fungicides and herbicides; however, interaction as evidenced by a reduction in total growth did occur between trifluralin and prometryne. Based on pesticides evaluated in this series of experiments, deleterious interactions as have been reported by other researchers to occur between herbicides and insecticides do not occur.