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ASSESSING AND IMPLEMENTING SUSTAINABLE ALTERNATIVES FOR POTATO PLANT PROTECTION
Thesis   Open access

ASSESSING AND IMPLEMENTING SUSTAINABLE ALTERNATIVES FOR POTATO PLANT PROTECTION

lora Lee keyte
Washington State University
Master of Science (MS), Washington State University
05/2025
DOI:
https://doi.org/10.7273/000007399
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Open Access CC BY V4.0

Abstract

biopesticide Cellulose nanofiber CNF kaki-tannin persimmon-derived tannin potato Botany
Potatoes (Solanum tuberosum L.) are an important economic crop in the U.S., particularly in the Pacific Northwest. However, early blight and late blight caused by Alternaria solani and Phytophthora infestans, respectively - both polycyclic diseases can cause severe yield losses. Current disease management relies heavily on synthetic chemical pesticides, which face challenges including development of pathogen strains resistant to pesticides, high costs, and concerns over environmental and human health impacts. Thus, this study explores sustainable alternatives by evaluating the potential of cellulose nanofiber (CNF) and persimmon-derived tannin (TANP) as biopesticides. CNF, derived from plant material, is an inert and elastic biomaterial widely used in various industries. The two types of CNF used in this study were derived from wood pulp or bamboo, and produced a low-resolution material and high-resolution material respectively. TANP, also known as kaki-tannin, exhibits strong antioxidant and antimicrobial properties. The hypothesis in this study is that CNF and TANP can protect plants from a range of potato diseases. The efficacy of CNF and TANP against A. solani and P. infestans was assessed using detached leaf assays, alongside evaluations of their effects on soil microbial communities and potential phytotoxicity. Results showed that neither treatment negatively impacted soil microbiota. While TANP have no adverse effects on plant growth or development, lower-resolution CNF caused foliar curling, whereas higher-resolution CNF did not significantly affect plant growth. Detached leaf assays revealed that TANP significantly suppressed infection by P. infestans in a dose-dependent manner but was likely ineffective against A. solani at the concentrations tested. In contrast, CNF did not provide protection against either pathogen and, in some detached leaf assays it appeared to inconsistently increase infection levels of both pathogens. In vivo assays suggest that CNF is not a viable candidate for managing early blight and late blight, whereas TANP holds promise as a biopesticide for controlling P. infestans, offering a potential environmentally sound alternative to synthetic fungicides. Future greenhouse and field trials will be necessary to further validate TANP’s efficacy and feasibility for integration into commercial agricultural practices.

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