It's mainly because the effect of biocontrol agents is not as good as chemical fungicide and the fermentation technology of biocontrol agents is not so perfect.

Downy mildew is one of the most serious grape diseases, the usual treatment method presently is the application of chemical fungicide, but excessive spray brings many severe problems.

Fungicide a chemical that inhibits fungal growth. they are used to prevent fungal infection as well as to deal with existing infections.