Microbes in Human Welfare

$Trichoderma$ species are free-living fungi that are very common in root ecosystems; they are effective biocontrol agents of several plant pathogens (i.e., of plant diseases).
Baculoviruses (genus $Nucleopolyhedrovirus$) are pathogens that attack insects and other arthropods; they control insect pests, not plant diseases.
$Bacillus\ thuringiensis$ is used to control butterfly caterpillars (insect pests).
$Glomus$ is a mycorrhizal fungus used as a biofertiliser.
Hence the common biocontrol agent for plant diseases is $Trichoderma$.

Organic farming uses biofertilisers and natural processes in place of chemical fertilisers.
$Glomus$ is a fungus that forms mycorrhiza and helps the plant to absorb phosphorus.
$Oscillatoria$ is a nitrogen-fixing cyanobacterium that adds organic matter and nitrogen to the soil.
Earthworms break down organic matter and are used to make vermicompost.
Snails are not used; they feed on crop plants and are pests.
Hence the snail is not used in organic farming.