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POSTERS: Biological control

The potential of herbal essential oils to control pulse crop pathogens.
Lipi Parikh - Montana State University. Bright Agindotan- Montana State University, Mary Burrows- Montana State University

The cultivation of chickpea, lentil, and dry peas (pulse crops) are on the rise in the United States, from 1.4M acres in 2013 to 2.5M acres in 2018. Many major diseases of these pulse crops are fungal in origin. These diseases reduce seed quality, crop establishment, and potential yield. Currently, these diseases are controlled primarily by chemical fungicides where resistant varieties are not available. The market for organically produced chickpea and pea is growing with different uses leading to an increase in demand. In the current study, 38 commercially available essential oils were screened to evaluate their in vitro inhibitory effects on Aphanomyces euteiches, Botrytis cinerea, Collectotrichum truncatum, Didymella pisi, D. rabiei, D. lentis, Fusarium avenaceum, Pythium ultimum, Stemphyllium globosum, and Sclerotinia sclerotiorum. Essential oil-infused agar toxicity method was used to determine the percent fungal growth inhibition, and essential oils with >60% pathogen inhibition across 10 pathogens were evaluated for inhibition of spore germination and the fungicidal/fungistatic effects of their volatile in inverted petri-plate assay. Palmarosa, oregano, clove, cinnamon, lemongrass, citronella, and thyme oils showed 100% growth inhibition of the fungi at concentrations ranging from 1/1000 to 1/4000. These essential oils also inhibited spore germination by 22-100%. The oils were either fungistatic or fungicidal. The herbal oils with efficacy in vitro are currently being investigated for use in vivo for potential use in organic and conventional production systems.