Synergy of the mixture of Curvularia eragrostidis strain QZ-2000 and low-rate herbicide to Digitaria sanguinalis indicated by some physiological parameters.

Curvularia eragrostidis strain QZ-2000 has a potential for biological control of large crabgrass(Digitaria sanguinalis).Its control efficacy,which is affected by environmental humidity conditions,can be improved and the dependence on the environment can be reduced through application of the mixture of Curvularia eragrostidis strain QZ-2000 conidia and low-rate herbicide.It is difficult to assess conidia or herbicide playing a main role in synergy only based on injured morphological symptoms of large crabgrass.The chlorophyll,soluble protein and MDA content in treated large crabgrass leaves were tested to enunciate the change of those physiological parameters and analyze the synergistic mechanism.The results showed chlorophyll and soluble protein content decreased and MDA content increased in all treatments.The mixture of conidia and low-rate herbicide demonstrated the most significant decrease of chlorophyll and soluble protein content while the most significant increase of MDA content.This indicated that there was synergy between conidia and low-rate herbicide,in which conidia played the predominant role.