Fungal Endophytes As a Control Method for Western Flower Thrips? A Study of Seven Candidate Fungi and Their Effect on Thrips Feeding and Reproduction in Cotton

Control of Western Flower Thrips(WFT), Frankliniella occidentalis, in early stage cotton has largely been dependent on insecticide usage. Resistance to insecticides as well as environmental concerns requires new approaches to be taken in controlling WFT. One possible control method is through the use of fungal endophytes. Previous studies have shown negative reproductive effects on many insect pest species when feeding on plants inoculated with fungal endophytes. For this study, the effects of seven independent fungal species were assessed on the feeding and reproduction of WFT in cotyledon stage cotton. Individual female WFT were exposed to inoculated cotton cotyledons for three days using a novel caging technique, then removed to count total feeding area. Four days later, the total number of emerged larvae was counted. The exposed leaf tissue was then stained to count inviable eggs that did not hatch. The remaining plant tissue was used to confirm positive colonization of the candidate endophyte. There was a significant overall effect of endophyte treatment on the total feeding area and number of hatched eggs per plant.  The results indicate that WFT can be adversely impacted by the selective inoculation of fungal endophytes in early stage cotton.  However, additional studies are need to confirm efficacy in the field.