Evaluation of fungicides for the management of sclerotinia blight of peanut

Abstract

Three trials were conducted in the Burnett region of southern Queensland, Australia, in the 1993–94 and 1994–95 seasons to determine the efficacy of fluazinam, procymidone, and iprodione for managing sclerotinia blight of peanut. Different combinations of rates, nozzle types, and spraying times were used in each trial. Two or 3 sprays of fluazinam at 0.75 and 1.0 kg a.i./ha, and of procymidone at 0.688 and 0.75 kg a.i./ha, were the most effective combinations that reduced disease incidence and increased yield. Iprodione at rates up to 0.5 kg a.i./ha did not significantly improve the yield compared with unsprayed treatments in any trial. In one trial at Tingoora in 1994–95, pre-infection treatments in which the first spray of fluazinam or procymidone was applied before symptoms appeared were more effective than post-infection treatments in which the first spray was applied soon after symptoms were seen. At J. Bjelke-Petersen Research Station (JBPRS) in 1994–95, a banded spray of procymidone at 0.688 kg a.i./ha using a single flat-fan 8004VB nozzle centred over the row significantly increased yield and reduced disease incidence compared with a spray using 3 hollow-cone nozzles (HB4-70) per row, with 1 nozzle over the row and 1 drop nozzle on each side of the row directed at the bases of the plants. At JBPRS in 1993–94, a band spray of fluazinam at 0.333 kg a.i./120 L.ha, applied with a single flat-fan 80015EVB nozzle immediately after the appearance of symptoms, was as effective in reducing the rate of disease development for 3 weeks, as was a directed application using three 80015EVB nozzles at the same time and concentration, but at 3 times the rate per area (1.0 kg a.i./360 L.ha).