Evaluation of fungicides for the management of sclerotinia blight of peanut

Three trials were conducted in the Burnett region of southern Queensland, A ustralia, in the 1993-94 and 1994-95 seasons to determine the efficacy of f luazinam, procymidone, and iprodione for managing sclerotinia blight of pea nut. 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./h a, 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 comp ared with unsprayed treatments in any trial. In one trial at Tingoora in 19 94-95, pre-infection treatments in which the first spray of fluazinam or pr ocymidone was applied before symptoms appeared were more effective than pos t-infection treatments in which the first spray was applied soon after symp toms 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 8 004VB nozzle centred over the row significantly increased yield and reduced disease incidence compared with a spray using 3 hollow-cone nozzles (HB4-7 0) per row, with 1 nozzle over the row and 1 drop nozzle on each side of th e row directed at the bases of the plants. At JBPRS in 1993-94, a band spra y of fluazinam at 0.333 kg a.i./120 L.ha, applied with a single flat-fan 80 015EVB nozzle immediately after the appearance of symptoms, was as effectiv e in reducing the rate of disease development for 3 weeks, as was a directe d application using three 80015EVB nozzles at the same time and concentrati on, but at 3 times the rate per area (1.0 kg a.i./360 L.ha).