Identification,Biological Characteristics And Prevention And Control Technology Of Grapevine Anthracnose

Anthracnose,caused by a fungus of the genus Colletotrichum spp.is an important disease in grape production and is widespread in vine growing regions worldwide.The fungus can infect fruit,leaves and branches,causing fruit rot and branch dieback.In recent years,the occurrence of grapevine anthracnose has increased year by year with the expansion of grape cultivation in Ningxia,the extension of cultivation years and the northward shift of rainbands,but few studies have been reported on the identification and control of the pathogen of grapevine anthracnose in the region.In this study,grapevine anthrax samples were collected and isolated in Ningxia from June to October 2022,and the pathogenic species were identified through morphological identification,pathogenicity determination and multi-gene phylogenetic analysis.On this basis,we carried out research on the chemical and biological control technologies of grapevine anthracnose to provide theoretical basis and basic support for the control of grapevine anthracnose in Ningxia.The main research results are as follows:1.A total of 24 purified pathogenic strains were obtained by tissue isolation from grapevines and leaves suspected of being infected with anthracnose,and their pathogenic species were identified by morphological identification,pathogenicity determination and multi-gene phylogenetic analysis.The results showed that Colletotrichum destructivum,C.fructicola and C.siamense were the main pathogens of grapevine anthracnose in Ningxia,and that the pathogenicity of C.siamense was significantly higher than that of C.fructicola and C.destructivum using the prick inoculation method.The pathogenicity of C.siamense was significantly stronger than that of C.fructicola and C.destructivum.2.The three representative strains of C.fioriniae and four exogenous anthrax species were used as materials.C.plurivorum,C.sichuanense and C.cymbidiicola can cause grapes to exhibit symptoms similar to those of anthracnose.The results showed that the strains grew well on media with fructose,maltose,soluble starch and glucose as carbon sources,but less well on media with mannitol as carbon source;the strains grew well on media with peptone,yeast paste and tryptone as nitrogen sources,but less well on media with potassium as nitrate source.All strains grew well at pH 4 to 10.The lethal temperature was 52℃ for C.destructivum,C.fructicola,C.siamense and C.fioriniae,and 55℃ for C.sichuanense,C.cymbidiicola and C.plurivorum.3.The virulence of different fungicides and their combinations against Colletotrichum siamense was determined by the mycelial growth rate method,and the effectiveness of the combinations on the control of grapevine anthracnose was evaluated in an in vitro test.The results showed that 500 g/L fludioxonil suspension inhibited the mycelial growth of grapevine anthracnose with an EC50 value of 0.0638 μg/mL;the inhibition effect of fludioxonil and tebuconazole was significantly stronger than that of fludioxonil and tebuconazole alone with an SR of 10.3772.In vitro control effect,the best preventive effect was achieved when fludioxonil was combined with tebuconazole at a mass ratio of 1:3,with a prevention efficiency of 85.99%.And the best curative effect was achieved when fludioxonil was combined with tebuconazole at a mass ratio of 1:1,with a curative effect of 88.89%.4.The eight endophytic fungal strains of bitter bean seeds were used as antagonistic screening materials,and the grapevine anthracnose pathogen(C.siamense)was used as the target fungus to investigate the inhibitory activity of the eight endophytic fungal strains of bitter bean seeds against grapevine anthracnose using the in-dish standoff method,mycelial growth rate method,spore germination method and in vitro efficacy test.The results showed that all eight strains of bitter bean endophytic fungi showed significant inhibitory effect on grapevine anthracnose.The inoculation of the endophytic fungus strain HD35(Alternaria alternata)for 3 d before inoculation with the pathogenic fungus showed the highest inhibition rate of 85.47%;the fermentation filtrate of strain HD35 at a concentration of 25%showed the highest inhibition rate of 80.25%against the mycelial growth of C.siamense;the fermentation filtrate of strain HD31(Fusarium solani)showed the highest inhibition rate of 80.25%.The HD31(Fusarium solani)strain had the highest inhibition rate of 83.07%on germination of C.siamense spores at a concentration of 40%in the fermentation filtrate;the volatile material produced by the HD31 strain at 6 d pre-inoculation had the highest inhibition rate of 82.09%on C.siamense.The results of the isolated efficacy test showed that the HD31 strain was the most effective in controlling grapevine anthracnose 7 d after the grape isolates had been wounded and inoculated with grapevine anthracnose cake,with an efficacy of 85.59%.This indicates that strain HD13 is a good starting bacterium for research on green control technology of grapevine anthracnose.