Fungal Endophytes and Their Ecological Roles in Cotton: Evaluation of Potential Antagonistic Activity against Plant Parasitic Nematodes and Insect Herbivores

Abstract

Results showed that both endophytes could negatively affect root-knot nematode infection and reproduction in cotton under greenhouse conditions. Further, endophytic C. globosum was also shown to negatively affect the fecundity of both cotton aphids and beet armyworms in greenhouse trials. C. globosum as an endophyte in cotton also affected the development rates and growth of beet armyworm larvae. This was the first study to demonstrate the negative effects of a since fungal endophyte, C. globosum, on insect herbivores feeding above-ground as well as plant parasitic nematodes feeding below-ground, using the same host plant species.

Across two years of field trials evaluating efficacy of the endophytes against nematodes, no significant effects of either P. lilacinum or C. globosum were detected on root-knot or reniform nematode populations. However, positive effects on cotton plant growth and yields were observed in some treatments combinations of endophyte genotype, seed treatment and plant genotype at some sites, indicating the importance of ontext dependency in determining the outcome of cotton-endophyte-nematode interactions in the field.

The results of this study indicate that the presence of fungal endophytes in crops can be manipulated and many have the potential to be incorporated as part of an IPM strategy to protect plants against both insect herbivores and plant parasitic nematodes. This novel approach may help provide an environmentally-sound and sustainable tool for pest management in agricultural systems in which the application of pesticides is currently the most commonly utilized control tactic.