Browsing by Author "Pulkoski, Melissa"

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    Influence of Fungicide Application on Rhizosphere Microbiota Structure and Microbial Secreted Enzymes in Diverse Cannabinoid-Rich Hemp Cultivars
    Xu, Junhuan; Knight, Tyson; Boone, Donchel; Saleem, Muhammad; Finley, Sheree J.; Gauthier, Nicole; Ayariga, Joseph A.; Akinrinlola, Rufus; Pulkoski, Melissa; Britt, Kadie; Tolosa, Tigist; Rosado-Rivera, Yara I.; Iddrisu, Ibrahim; Thweatt, Ivy; Li, Ting; Zebelo, Simon; Burrack, Hannah; Thiessen, Lindsey; Hansen, Zachariah; Bernard, Ernest; Kuhar, Thomas; Samuel-Foo, Michelle; Ajayi, Olufemi S. (MDPI, 2024-05-28)
    Microbes and enzymes play essential roles in soil and plant rhizosphere ecosystem functioning. However, fungicides and plant root secretions may impact the diversity and abundance of microbiota structure and enzymatic activities in the plant rhizosphere. In this study, we analyzed soil samples from the rhizosphere of four cannabinoid-rich hemp (Cannabis sativa) cultivars (Otto II, BaOx, Cherry Citrus, and Wife) subjected to three different treatments (natural infection, fungal inoculation, and fungicide treatment). DNA was extracted from the soil samples, 16S rDNA was sequenced, and data were analyzed for diversity and abundance among different fungicide treatments and hemp cultivars. Fungicide treatment significantly impacted the diversity and abundance of the hemp rhizosphere microbiota structure, and it substantially increased the abundance of the phyla Archaea and Rokubacteria. However, the abundances of the phyla Pseudomonadota and Gemmatimonadetes were substantially decreased in treatments with fungicides compared to those without fungicides in the four hemp cultivars. In addition, the diversity and abundance of the rhizosphere microbiota structure were influenced by hemp cultivars. The influence of Cherry Citrus on the diversity and abundance of the hemp rhizosphere microbiota structure was less compared to the other three hemp cultivars (Otto II, BaOx, and Wife). Moreover, fungicide treatment affected enzymatic activities in the hemp rhizosphere. The application of fungicides significantly decreased enzyme abundance in the rhizosphere of all four hemp cultivars. Enzymes such as dehydrogenase, dioxygenase, hydrolase, transferase, oxidase, carboxylase, and peptidase significantly decreased in all the four hemp rhizosphere treated with fungicides compared to those not treated. These enzymes may be involved in the function of metabolizing organic matter and degrading xenobiotics. The ecological significance of these findings lies in the recognition that fungicides impact enzymes, microbiota structure, and the overall ecosystem within the hemp rhizosphere.
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    Pest Management Needs and Limitations for Corn Earworm (Lepidoptera: Noctuidae), an Emergent Key Pest of Hemp in the United States
    Britt, Kadie E.; Kuhar, Thomas P.; Cranshaw, Whitney; McCullough, Christopher T.; Taylor, Sally V.; Arends, Benjamin R.; Burrack, Hannah; Pulkoski, Melissa; Owens, David; Tolosa, Tigist A.; Zebelo, Simon; Kesheimer, Katelyn A.; Ajayi, Olufemi S.; Samuel-Foo, Michelle; Davis, Jeffrey A.; Arey, Nathan; Doughty, Hélène; Jones, Joanne; Bolt, Marguerite; Fritz, Bradley J.; Grant, Jerome F.; Cosner, Julian; Schreiner, Melissa (Oxford University Press, 2021-09-11)
    Corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), has emerged as an injurious insect pest to hemp, Cannabis sativa L., a crop newly reintroduced to the United States. Growing hemp presents a potential alternative economic opportunity for farmers but can be challenging with a market that is unstable and just developing. One of the most notable production challenges is managing corn earworm, an insect pest that is particularly damaging when it feeds on flower buds produced in cannabinoid varieties, creating extensive bud tunneling and wounds that allow entry of pathogens that can aid development and presence of bud rot. Damage to seeds is of lesser concern in hemp cultivars grown for grain and minimal risk is associated with hemp grown for fiber. Our ability to research hemp has only recently been allowed as production was largely suspended following World War II and, as such, there has been limited opportunity to develop information for empirically-based pest management recommendations. Further complicating development of integrated pest management (IPM) strategies are regulatory challenges associated with providing registration support to add hemp to pesticide labels, as it was not formally recognized as a crop by U.S. regulatory agencies until late 2019. Research needs and challenges to develop effective IPM programs for corn earworm on hemp are discussed here.