Test of Toxicity of Fungicides and Screening for Synergistic Effect Ratio of Mixtures against Fusarium proliferatum Causing Mango Malformation

In order to control mango malformation which was a new disease of mango in China and identified to be caused by Fusarium proliferatum,toxicities of nine fungicides against F.proliferatum were tested using the mycelia growth rate method.Both the EC50 value and slope rate of toxicity regression equation of each fungicide were determined.Prochloraz with EC50 value of 0.075 μg/mL and slope rate of 0.85,and carbendazim with EC50 value of 0.3 μg/mL and slope rate of 3.69,showed the highest application potential,followed by tebuconazole(EC50 0.36 μg/mL),propiconazole(EC50 0.84 μg/mL),flusilazole(EC50 0.84 μg/mL),carbendazim-thiram-bromothalonil(EC50 1.27 μg/mL)and thiophanate-methyl(EC50 1.74 μg/mL).Among 29 combinations of nine fungicides,three ratios were showed synergistic effect.The combination between propiconazole and carbendazim-thiram-bromothalonil at a 2 ∶ 3 showed the largest synergistic effect.Combinations between prochloraz and carbendazim-thiram-bromothalonil in the ratios 1 ∶ 4,carbendazim-thiram-bromothalonil and thiophanate-methyl in the ratios 2:3 also showed synergistic effects.The rest combinations had additive or antagonistic effect.