Fungi found in cotton can decrease root knot nematode galling
(PHYSorg.com Biology)

Texas A&M University scientists found that a surprising number of fungi naturally associated with cultivated cotton were capable of curtailing the negative effects of a plant parasite known as the Southern root knot nematode, an economically damaging pest of cotton with the ability to significantly reduce yields. These fungi live in the soil or even inside of the cotton plants themselves but their effects on plant health have been mostly overlooked.