Initial Studies on Beneficial Fungi that Can Live Inside Pecan Trees and Provide Protection from Insects and Disease

Authors: Shapiro Ilan, David; RAMAKUWELA, TSHIMANGADZO - Agricultural Research Council Of South Africa; Bock, Clive; HATTING, JUSTIN - Aapresid; Vega, Fernando; WELLS, LENNY - University Of Georgia; MBATA, GEORGE - Fort Valley State University

Submitted to: Pecan Grower
Publication Type: Trade Journal
Publication Acceptance Date: 9/24/2020
Publication Date: 10/1/2020
Citation: Shapiro Ilan, D.I., Ramakuwela, T., Bock, C.H., Hatting, J., Vega, F.E., Wells, L., Mbata, G. 2020. Initial Studies on Beneficial Fungi that Can Live Inside Pecan Trees and Provide Protection from Insects and Disease. Pecan Grower. 23(5): 50-58.

Interpretive Summary: Entomopathogenic (aka beneficial) fungi are commercially available as biopesticides that are used to control a wide variety of economically important insect pests in various cropping systems. Some of these fungi, including Beauveria bassiana, can kill pecan pests such as pecan weevil and pecan aphids. When used commercially, the beneficial fungi are generally applied to the crop using standard spray equipment. However, certain beneficial fungi, for example, B. bassiana, have also been found to kill insect pests when living inside plants as endophytes. An endophyte is a microorganism (often fungi or bacteria) that lives inside a plant without causing disease. Conceivably, if endophytic fungi can protect a plant from insects or disease, then treatment costs may be lower compared with spray programs. We discovered that two beneficial fungal species (B. bassiana and Metarhizium brunneum) can be inoculated into pecan tree seedlings and subsequently exist as endophytes. Moreover, we discovered that the established endophytic fungi can provide protection to pecan. In laboratory and greenhouse tests we observed reduced survival in pecan aphids and reduced growth of the pecan disease, Phytophthora shuck and kernel rot. In future research we will expand our studies to determine the potential for the endophyte approach under field conditions.

Technical Abstract: Entomopathogenic fungi are used to control a wide variety of economically important insect pests in various cropping systems. Some of these fungi, including Beauveria bassiana, can kill pecan pests such as pecan weevil (Curculio caryae) and pecan aphids. When used commercially, the beneficial fungi are generally applied to the crop using standard spray equipment. However, certain beneficial fungi, for example, B. bassiana, have also been found to kill insect pests when living inside plants as endophytes. Conceivably, if endophytic fungi can protect a plant from insects or disease, then treatment costs may be lower compared with spray programs. We discovered that two beneficial fungal species (B. bassiana and Metarhizium brunneum) can be inoculated into pecan tree seedlings and subsequently exist as endophytes. Moreover, we discovered that the established endophytic fungi can provide protection to pecan. In laboratory and greenhouse tests we observed reduced survival in pecan aphids and reduced growth of the pecan disease, Phytophthora shuck and kernel rot. In future research we will expand our studies to determine the potential for the endophyte approach under field conditions.