Developing integrated pest management (IPM) strategies for hemp russet mite (Aculops cannabicola Farkas) on hemp (Cannabis sativa L.)
Date
2022
Authors
Hayes, Christopher, author
Nachappa, Punya, advisor
Cranshaw, Whitney, advisor
Prenni, Jessica, committee member
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Abstract
Cannabis sativa L. is a plant that is rapidly becoming a crop of global agricultural importance. However, because of the historical peculiar regulatory status of this crop little has been developed on the pests and pest management needs of the crop. Among the more serious pests that have become established with this plant is hemp russet mite (HRM) Aculops cannabicola Farkas (Acari: Eriophyidae). In order to assess the efficacy of various IPM approaches to mitigating HRM infestations, a series of field and lab experiments were conducted including: 1) evaluation of the effects of sprays of sulfur on control of hemp russet mite, yield, and cannabinoid produduction; 2) evaluation of the efficacy of field release of the phytoseiid mites Amblyseius andersoni, A. swirskii, Neoseiulus fallacis, and N. californicus on HRM-infested hemp plants; and 3) evaluation of hot water immersion as a potential disinfestation method for HRM-infested cuttings used in propagation. The results of the sulfur sprays in field trials showed excellent ability to suppress HRM by up to 98%. Yields of treated plants improved by up to 33% and there was a further increase in the percentage of phytocannabinoids by up to 45% relative to untreated plants. Greatest effects were seen in all trials with plants receiving two applications, one during the vegetative period in July and the second at the initiation of flower production in August. Mass releases of N. fallacis and A. swirskii, but not N. californicus and A. amblysieus, did produce a significant reduction in HRM populations, but no treatments significantly affected yield or percentage of phytocannabinoids, relative to untreated plants. No reproduction was observed of any of the released mites on HRM-infested plants. Immersion treatments to disinfest cuttings included use of a water bath at temperatures of 106°F or 109°F for 10 or 15 minutes, and dips in room temperature surfactant solution of Dr. Bonner's Pure-Castile lavender soap at 1.0% and 0.1% concentrations. All treatments were able to cause significant reduction of HRM on infested hemp cuttings, although none caused complete elimination. No phytotoxicity, as evidenced by effects on subsequent rooting, were observed with any treatment. This study provides novel effective approaches to mitigating HRM at multiple stages in hemp production operations. Outcomes of this research may provide hemp producers and other stakeholders with key pest management strategies needed to produce hemp plants that are free of HRM.
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Subject
Cannabis sativa
hemp russet mite
IPM
hemp
Aculops cannabicola
industrial hemp