Semester of Graduation

Summer 2022

Degree

Master of Science (MS)

Department

Entomology

Document Type

Thesis

Abstract

Hemp, Cannabis sativa (L.) (Rosales: Cannabaceae), is defined as a plant in the genus Cannabis with a delta-9 3 tetrahydrocannabinol (THC) concentration of not more than 0.3% on a dry weight basis. Domestic acreage of this crop has increased in response to the ratification of the Agricultural Act of 2014 and the Agricultural Improvement Act of 2018. In 2021, 21,915 hectares of hemp were planted in the United States with a production value of $712 million. There is a current lack of literature on insect related research in this reemerging crop system in the state of Louisiana. Therefore, this present study aimed to 1) Conduct a faunistic survey of hemp in Louisiana 2) Evaluate hemp as an alternative host plant for polyphagous lepidopterans in the family Noctuidae that are present in the Louisiana agroecosystem 3) Conduct laboratory-based efficacy tests of registered pesticides available to growers against these noctuid pests.

Arthropod sampling of hemp revealed a diverse complex of specimens with polyphagous associations to hemp and a robust group of natural enemies that hemp growers should be aware of when making pest management decisions. Life history studies evaluating the host plant viability of Chrysodeixis includens (Walker), Spodoptera frugiperda (J.E. Smith), and Spodoptera exigua (Hübner) revealed consumption of hemp leaf material resulted in shorter preadult developmental times and positively impacted select life history parameters when compared to documented host plants. Diet overlay and leaf dip laboratory bioassays were conducted to provide Louisiana hemp growers with efficacy data for currently registered pesticides for use against these three noctuid pests. Products containing the active ingredients azadirachtin, potassium salts of fatty acids, and Bacillus thuringiensis (Bt) ssp. kurstaki resulted in high levels of control for these noctuid pests on treated artificial diet. Consumption of leaf material treated with products containing the active ingredients Bt ssp. kurstaki and azadirachtin resulted in high levels of mortality for C. includens and S. frugiperda five days after treatment. Leaf material treated with products containing pure neem oil azadirachtin, and Bt ssp. kurstaki resulted in high levels of mortality for S. exigua five days after treatment.

Date

7-15-2022

Committee Chair

Davis, Jeffrey A.

DOI

10.31390/gradschool_theses.5614

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