In vitro efficacy of fungal endophytes and silver pyrazolate against Raffaelea lauricola, causal agent of laurel wilt of avocado

Authors

Kiara Taibi-Briz, Agroecology Program, Earth and Environment Department, Florida International University,Follow
Krish Jayachandran, Agroecology Program, Earth and Environment Department, Florida International University,Follow
Raphael G. Raptis, Department of Chemistry and Biochemistry and the Biomolecular Sciences Institute, Florida International UniversityFollow
Kateel G. Shetty, Agroecology Program, Earth and Environment Department, Florida International University,Follow

Faculty Advisor

Kateel G. Shetty

Author Biographical Statement

Kiara Taibi-Briz graduated from FIU in Spring 2022 with a Bachelor of Science in Environmental Studies focusing on agroecology. During her time at FIU, she served as the Garden Club President from Fall 2021 to Spring 2022 and as the Garden Manager in Spring 2022. Kiara has been working under the guidance of Dr. Kateel Shetty in the agroecology microbiology lab since Fall 2018. Kiara has presented in the 2021 and 2022 FIU Honors Undergraduate Research Conference. Kiara hopes to continue her education and receive a master’s degree in Environmental Studies in the near future.

Abstract

The South Florida avocado industry is being severely impacted by laurel wilt disease. Laurel wilt disease of avocado is caused by the fungal pathogen, Raffaelea lauricola (RL) and is vectored by ambrosia beetle, Xyleborus glabratus. Treatments options are limited, economically not sustainable, and require reapplication fungicides every couple of years. There is a crucial need for developing multiple modes of control using novel biological and chemical agents. The ambrosia beetle associated pathogenic fungi are known to outcompete other microorganisms by taking advantage of ethanol produced by the pathogen and the stressed tree. Endophytes, which reside inside the host plant tissue are part of the plant microbiome represent source of new potential biological control agents. In this study, three ethanol tolerant endophytic fungal species, isolated from avocado bark, were evaluated using in vitro dual culture assay and colonization tube (packed with bark/sapwood shaving) against RL. The endophytic isolates Tricoderma crissum, Tricoderma simmonsii, Lasiodiplodia theobromae were found to be highly capable of suppressing the mycelial colony growth of RL. The results suggest that combined abilities of ethanol tolerance and competitive colonization can provide useful criteria for identifying potential biocontrol agents. In vitro anti-RL activity of silver pyrazolate compound was assessed in both agar and liquid medium. Silver pyrazolate at levels of 30 and 45 ppm were found to be highly effective against RL. Further in planta research is needed to study the effects of endophytic fungal isolates and silver pyrazolate to assess their potential as additional tools for management of laurel wilt.

DOI

10.25148/URJ.010323

Recommended Citation

Taibi-Briz, Kiara; Jayachandran, Krish; Raptis, Raphael G.; and Shetty, Kateel G. (2023) "In vitro efficacy of fungal endophytes and silver pyrazolate against Raffaelea lauricola, causal agent of laurel wilt of avocado," FIU Undergraduate Research Journal: Vol. 1: Iss. 1, Article 4.
DOI: 10.25148/URJ.010323
Available at: https://digitalcommons.fiu.edu/undergraduate-journal/vol1/iss1/4