Reduced Fungicide Inputs in Winter Wheat

Abstract

Nine trials were conducted over three years at three sites to evaluate the efficacy of reduced rates of various fungicide products for their biological efficacy in controlling stem, foliar and ear diseases of winter wheat as well as their effects on yield and grain quality, and to compare the relative profitability of full and reduced rates of fungicides. The results show that the use of half rates can give an economic benefit over that of full rates in many situations. In circumstances where variety or seasonal factors resulted in low to moderate foliar disease pressure the use of half rates gave similar yields to that of full rates. Where foliar disease pressure was high, half rates generally gave lower yields than full rates but the amount of the reduction varied with the fungicide product used. The use of spray additives improved the yield response of the half rate treatments in most cases. Disease levels (septoria) were higher in treatments where half rates were used, compared with the corresponding full rates, but the used of spray additives improved the disease control in the half rate treatments. The timing of spray applications is critical when half rates of fungicides are being used. Reduced rate treatments need to be applied more frequently. In these trials reduced rate treatments were applied as a three-spray programme rather than the conventional two-spray programme.