Biological Characteristics of <i>Alternaria</i> Leaf Blight of <i>Scaevola taccada </i>and Screening of Fungicides <i>in vitro</i>
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Chinese Journal of Tropical Crops ›› 2020, Vol. 41 ›› Issue (8): 1634-1641.DOI: 10.3969/j.issn.1000-2561.2020.08.018

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Biological Characteristics of Alternaria Leaf Blight of Scaevola taccada and Screening of Fungicides in vitro

WANG Yi1,2,HU Meijiao2,LI Min2,GAO Zhaoyin2,HONG Xiaoyu2,ZHANG Shaogang1,2,ZHAO Chao1,*()   

  1. 1. School of Life and Pharmaceutical Sciences, Hainan University / Key Laboratory of Tropical Biological Resources of Ministry of Education, Haikou, Hainan 570228, China
    2. Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences / Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Haikou, Hainan 571101, China
  • Received:2019-09-11 Revised:2019-11-03 Online:2020-08-25 Published:2020-09-17
  • Contact: ZHAO Chao


Alternaria leaf blight of Scaevola taccada is a common and serious disease in Xisha Island. The pathogen of the disease was identified as Alternaria longipes. To further clarify the biological characteristics of the pathogen and its sensitivity to fungicides. Therefore, in this study, the biological characteristics of A. longipes were preliminarily studied by the mycelium growth rate method, and the toxicological test of 13 fungicides such as difenoconazole to this pathogen was determined. The optimum growth medium was potato dextrose agar medium (PDA), followed by potato sugar agar medium (PSA). The suitable growth temperature was 25 to 30℃, and the optimum growth temperature was 28℃. The suitable pH value was 5.0 to 7.0, and the optimum pH value was 6.0. The optimal carbon source was sucrose, while fructose was not conducive to colony growth. The optimal nitrogen source was glycine, while urea was not conducive to colony growth. Light time had no significant effect on colony growth. Laboratory toxicity test showed that the best inhibition effect was found in difenoconazole water-dispersible granular with EC50 value of 0.15 μg/mL, followed by flusilazole emulsion, hexazolium suspension agent and penconazole emulsion, with EC50 values of 0.37, 0.44 and 0.51 μg/mL, respectively, while azoxystrobin suspension agent and carbendazol wettable powder had the worst inhibitory effect, with an EC50 value of more than 3000 μg/mL.

Key words: Scaevola taccada, Alternaria longipes, biological characteristics, fungicide, toxicological test

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