Role of endophytic entomopathogenic fungi in mediating host selection, biology, behavior, and management of tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae)

Authors: George, Justin; Glover, James; Perera, Omaththage; Reddy, Gadi V.P.

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2024
Publication Date: 7/23/2024
Citation: George, J., Glover, J.P., Perera, O.P., Reddy, G.V. 2024. Role of endophytic entomopathogenic fungi in mediating host selection, biology, behavior, and management of tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae). Plants. 13(15):1-17. https://doi.org/10.3390/plants13152012.
DOI: https://doi.org/10.3390/plants13152012

Interpretive Summary: Fungal endophytes can act as entomopathogens and play an essential role as biocontrol agents against a myriad of insect pests. They pose little or no harm to non-target insects and other beneficial organisms. This study investigated the potential of different endophytic, precisely Beauveria bassiana strains, in colonizing cotton plants and their efficacy against the tarnished plant bug Lygus lineolaris. The effect of endophytes on plant growth parameters and cotton yield were measured during different plant growth stages. The entomopathogenicity of these fungi was studied in diet cup bioassays using L. lineolaris adults. The behavior of adult males and females toward endophytic cotton squares was analyzed using olfactometer assays. Experiments showed that the fungal endophytes colonized the plant structures of cotton plants, which resulted in an increase in the number of cotton squares, plant height, and weight compared to control plants. B. bassiana strains/isolates such as GHA, NI-8, and JG-1 showed significant mortality in Lygus adults compared to controls. Also, male and female Lygus adults exhibited repellence behavior towards endophytic cotton squares containing JG-1 isolate of B. bassiana and to other B. bassiana strains such as NI-8, GHA, and SPE-120. No differences were observed in the survival and development of L. lineolaris 2nd instar nymphs on endophytic cotton, and no yield differences were observed in the field experiments. Our greenhouse and field experiments showed that these fungal endophytes can colonize different plant parts, impact the plant growth of cotton, and affect the biology and behavior of L. lineolaris adults and nymphs.

Technical Abstract: Non-insecticidal control strategies using entomopathogens, nematodes, and endophytes provide sustainable and safer alternatives for managing crop pests. This study investigated the potential of different endophytic, precisely Beauveria bassiana strains, in colonizing cotton plants and their efficacy against a tarnished plant bug, Lygus lineolaris. The effect of endophytes on plant growth parameters and cotton yield were measured during different plant growth stages. The entomopathogenicity of these fungi was studied in diet cup bioassays using L. lineolaris adults. The behavior of adult males and females toward endophytic cotton squares was analyzed using olfactometer assays. Experiments showed that the fungal endophytes colonized the plant structures of cotton plants, which resulted in an increase in the number of cotton squares, plant height, and weight compared to control plants. B. bassiana strains/isolates such as GHA, NI-8, and JG-1 showed significant mortality in Lygus adults compared to controls. Also, male and female Lygus adults exhibited repellence behavior towards endophytic cotton squares containing JG-1 isolate of B. bassiana and to other B. bassiana strains such as NI-8, GHA, and SPE-120. No differences were observed in the survival and development of L. lineolaris 2nd instar nymphs on endophytic cotton, and no yield differences were observed in the field experiments.