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[Objective]The paper was to study biological characteristics of Fusarium oxysporum f.sp.niveum in watermelon cultivated in plastic greenhouse in Hainan Province of China and to determine indoor toxicity of fungicides.[Method]Effects of various factors on mycelial growth and spore germination were studied,and the lethal temperature of spores and indoor toxicity of fungicides were also determined.[Result]The fungal mycelium had a better growth rate on watermelon juice medium than the others.The optimum temperature for mycelial growth and spore germination were 28℃and 30℃,and the optimum pH values were7-8 and 7-9,respectively.Light-dark alternation was conducive for mycelial growth.The lethal temperature of spore was 60℃for 5 min.The fungal mycelium grew better while taking fructose and glucose as carbon sources and yeast extract and peptone as nitrogen sources.Toxicity determination showed that 50%prochloraz-manganese chloride complex WP had the greatest inhibition effect on mycelial growth,with the EC50value of 0.730 9μg/mL;followed by 32.5%benzoic azoxystrobin SC,30%benzoylate·propiconazol EC,10%difenoconazole WG,25%bromothalonil·carbendazim WP and 25%bromothalonil WP,with the EC50values from 1.884 7μg/mL to 8.161 0μg/mL.[Conclusion]The study provided basic data for field control against F.oxysporum f.sp.niveum on watermelon cultivated in plastic greenhouse in Hainan Province.
[Objective] The paper was to study biological characteristics of Fusarium oxysporum f.sp.niveum in watermelon cultivated in plastic greenhouse in Hainan Province of China and to determine indoor toxicity of fungicides. [Method] Effects of various factors on mycelial growth and spore germination were studied, and the lethal temperature of spores and indoor toxicity of fungicides were also determined. [Result] The fungal mycelium had a better growth rate on watermelon juice medium than the others. optimum temperature for mycelial growth and spore germination were 28 ° C and 30 ° C, and the optimum pH values were 7-8 and 7-9, respectively. Light-dark alternation was conducive for mycelial growth. The lethal temperature of spore was 60 ° C for 5 min. The fungal mycelium grew better while taking fructose and glucose as carbon sources and yeast extract and peptone as nitrogen sources. Toxicity determination showed that 50% prochloraz-manganese chloride complex WP had the greatest inhibition effect on myceli followed by 32.5% benzoic azoxystrobin SC, 30% benzoylate propiconazol EC, 10% difenoconazole WG, 25% bromothalonil carbendazim WP and 25% bromothalonil WP, with the EC50 value of 1.884 7 μg / mL to 8.161 0 μg / mL. [Conclusion] The study provided basic data for field control against F. oxysporum f.sp.niveum on watermelon cultivated in plastic greenhouse in Hainan Province.