Negative Effects of the Entomopathogenic Fungal Endophytes Paecilomyces Lilacinus and Beauveria Bassiana On Cotton Aphid Reproduction in Greenhouse and Field Conditions

The effects of two entomopathogenic fungal endophytes, Beauveria bassiana and Paecilomyces lilacinus, on the reproduction of cotton aphid, Aphis gossypii Glover (Homoptera:Aphididae), were assessed after 7 and 14 days feeding on endophyte-colonized cotton in greenhouse conditions and at 14 days in field conditions. We provide the first report of a negative effect of endophytic P. lilacinus on an insect herbivore, as well as novel demonstrations of the negative endophytic effects of both P. lilacinus and B. bassiana on cotton aphids when tested in whole plant assays inoculated as seed treatments. In the greenhouse experiment, there was a significant decrease in aphid reproduction among insects feeding on plants inoculated with P. lilacinus after 7 days and at 14 days on plants inoculated with B. bassiana. Field trials showed a significant decrease in aphid numbers after 14 days on plants colonized with B. bassiana, but no decrease in aphid numbers on plants inoculated with P. lilacinus. Our results demonstrate the establishment of two entomopathogenic fungi as endophytes in cotton seedlings via seed inoculation and provide evidence of negative effects of these fungi as endophytes on cotton aphid reproduction. Our results illustrate the potential use of these fungal endophytes in planta as a biological control tool against other insect pests.