| 【Objective】The study was conducted to identify the pathogen causing anthracnose of Chrysanthemum
in Huaiji of Guangdong province, and to screen the best control agents in the field in order to provide guidance
for the prevention and control of Chrysanthemum anthracnose.【Method】Diseased samples (flowers and leaves)
of Chrysanthemum with anthracnose symptoms collected from Huaiji of Guangdong were isolated and cultured
conventionally. Fungal strains Cg1-1, Cg1-2 and Cg1-3 were isolated and obtained. The pathogenicity of above
strains were determined by the Koch’s postulates with in vivo and in vitro inoculation of conidial suspension on plants
of Chrysanthemum. The spores sizes and myelium morphologies of Cg1-1, Cg1-2 and Cg1-3 were observed under
microscope and polygene molecular identification was conducted with ribosomal transcription spacer (ITS), large subunit (LSU)、Chitin synthase (CHS1) and actin (ACT). Finally, Mega7.0.18 was used to construct the phylogenetic tree of Cg1-
1, Cg1-2 and Cg1-3 with the maximum natural method. Difenoconazole, Prochloraz, 30% Thifluzamide (Liangzun), 430 g/L
Tebuconazole (Cuijian) and 40% Thifluzamide·Trifloxystrobin (Runxiu) were used to control Chrysanthemum anthracnose
in the field.【Result】Through the analysis of the biological characteristics of pathogen and the identification of polygene
molecular biology, the anthracnose pathogen on Chrysanthemum in Huaiji of Guangdong Province is Colletotrichum
gloeosporioides. The field efficacy test results showed that 1 500 times Difenoconazole and 1 500 times Prochloraz has the
best control effects on the disease in the field. Attention should be paid to effective application of agents after the rain and
in the rapid growing season of Chrysanthemum.【Conclusion】C. gloeosporioides is the causative agent of anthracnose
on Chrysanthemum in Huaiji of Guangdong. 1 500 times Difenoconazole and 1 500 times Prochloraz can be used as
recommended agents for field control. |
