Recipient Organization
COLORADO STATE UNIVERSITY
(N/A)
FORT COLLINS,CO 80523
Performing Department
Agricultural Biology
Non Technical Summary
The recent passage of the Hemp Access and Consumer Safety Act has cleared the way for organic farmers to increase hemp acreage and organic brands to develop and diversify new organic hemp products. However, there are many challenges to producing an organic hemp crop, particularly with regards to pest management strategies. For instance, lack of knowledge on the impact of organic management on crop resistance to hemp pests, and lack of information on efficacy of OMRI-approved insecticides. Hence, the long-term goal of this multi-disciplinary project is to create a robust and resilient organic hemp production system against arthropod pests which will provide growers with management tools to improve crop health and sustainability.The long-term goals will be accomplished by the four specific objectives:Objective 1. Quantify the effects of organic production systems on plant resistance to hemp pests through changes in rhizosphere microbiome.Objective 2. Evaluate hemp cultivars for resistance to hemp pests in organic production systems.Objective 3. Determine the effectiveness of OMRI-approved insecticides in combination with biological control for suppression of hemp pests.Objective 4: Develop effective methods to provide research-based information to hemp growers and other stakeholders.These objectives will be addressed through field experiments in certified organic hemp fields that has been under organic production for over 19 years at the Agricultural Research, Development and Education Center at Colorado State University. The research we propose addresses USDA-OREI program priorities: (1) and (6) and legislated goals (1), (2) and (3).
Animal Health Component
20%
Research Effort Categories
Basic
60%
Applied
20%
Developmental
20%
Goals / Objectives
Long-term and short-term goalsOur long-term goal is to create a robust and resilient organic hemp production system against arthropod pests which will provide organic hemp growers with management tools to improve crop health and sustainability. To achieve this, our proposal will focus on the short-term goals of understanding the role of rhizosphere microbiome associated with plant resistance to pests, impact of organic inputs (resistant cultivars, OMRI-approved insecticides, and natural enemies) in reducing pest populations, and dissemination of these results (Fig. 2).The short-term goals of the project will be accomplished by the following four objectives:Objective 1. Quantify the effects of organic production systems on plant resistance to hemp pests through changes in rhizosphere microbiome. Hypothesis: Organic production improves plant resistance to arthropod pests through changes in rhizosphere microbial communities.Objective 2. Evaluate hemp cultivars for resistance to hemp pests in organic production systems. Hypothesis: There will be variability among hemp cultivars in host plant resistance to hemp pests in organic systems.Objective 3. Determine the effectiveness of OMRI-approved insecticides in combination with biological control for suppression of hemp pests. Hypothesis: Organic insecticides augmented by biological control can suppress key pests of hemp below damaging levels.Objective 4: Develop effective methods to provide research-based information to hemp growers and other stakeholders. Hypothesis: Access to information and recommendations for pest suppression in organic hemp production will increase adoption of sustainable pest management practices withing the context of IPM
Project Methods
Objective 1. Quantify the effects of organic production systems on plant resistance to hemp pests through changes in the rhizosphere microbiome.Methods and feasibility. The experimental design will be a completely randomized block with three replications/plots of each treatment (organic and conventional). For organic and conventional production, rooted clones of a certified CBD cultivar (Unicorn) will be excised from mother plants grown in the greenhouse at CSU and planted in the field at the end of May/first week of June. In each replicate or plot, seedlings will be transplanted into rows separated by 76 cm, and 91 cm spacing between each plant with 12 rows and 12 plants in each row.Pest, natural enemy sampling, and phytohormone analysis. At each field, 20 arbitrarily selected plants will be sampled for the two key hemp pest populations (cannabis aphids and hemp russet mites), natural enemies, leaf tissue and flowers, and rhizosphere sampling. Arthropod populations will be sampled three weeks after transplanting (early vegetative), 4-6 weeks (late vegetative), 6-8 weeks (flowering or anthesis) and 10-12 weeks (at harvest). Arthropods will be sampled by manually examining 10 leaves per plant and samples will be bagged and frozen until arthropods are sorted and counted (Fig. 8).During arthropod sampling, approximately 100 mg of developmentally similar true leaves from three hemp plants per field will be removed for phytohormone analysis. There will be a total of 72 plants sampled [2 treatments (organic vs conventional) x 3 plants x 4 sampling times x 3 replicates]. The samples will be stored in the -80°C until phytohormone analysis. Absolute quantitation of 18 phytohormones will be determined using an established targeted LC-MS assay developed in Co-PI Prenni's lab (Sheflin et al. 2019).Plant yield and cannabinoid analysis. At maturity, plant biomass will be measured as the mass of the aboveground portion of all the plants in each row. Plants will be cut at the soil surface and air-dried for a minimum of 30 days. The plants (including flowers and leaves without stem and branches) will then be weighed to determine yield. To analyze cannabinoid levels, hemp flower samples will be collected from six plants per replicate. Hence, a total of 2 treatments x 6 plants x 3 replicates =36 plants). Dried flower samples will be homogenized using a bead beater and phytochemicals will be extracted using established protocols in Co-PI Prenni lab. Samples will be analyzed using a targeted liquid chromatography mass spectrometry (LC-MS) quantitative assay for 20 cannabinoids (Bowen et al. 2021) (Fig. 8). Individual plants within each replication/plot will be pooled for yield and quality determination.Rhizosphere sampling. In each replication/plot, the same 20 plants sampled for pest and natural enemies will be targeted for rhizosphere sampling. The loosely attached soil on the roots will be carefully removed. The rhizosphere soil will be collected by gently brushing the remaining soil adhering to the roots using brush pencils. There will be a total of 120 samples [2 treatments (organic vs conventional) x 20 plants x 3 replicates]. DNA will be extracted using Qiagen PowerSoil® DNA isolation kit following the manufacturer's instructions. Extracted DNA will be quantified using Qubit and stored at -80°C until further use. PCR will be performed targeting the V4 region of the bacterial 16S rRNA gene using primer-pair 515F?806R (Caporaso et al. 2012) and sequencing will be done at the Colorado State University Next Generation Sequencing facility (Fort Collins, USA) through Illumina MiSeq 2x 300 bp paired end sequencing.Objective 2. Evaluate hemp cultivars for resistance to hemp pests in organic production systems. Methods and feasibility.The experiment will be comprised of 30 different hemp lines, planted in a randomized complete block design with three replications/plots. Each plot will consist of 30 plants planted in six row that are 6.1 m in length with approximately 0.25 m spacing between rows. Plants will be naturally infested with pests throughout the season. We will monitor populations of hemp russet mite and cannabis aphids at the same time-points described in Objective 1: early vegetative, late-vegetative, flowering or anthesis and at harvest (Fig. 8). At maturity, plant biomass will be measured as the mass of the aboveground portion of all the plants in a plot. The dried hemp flower samples from three plants per replicate/plot will be combined and submitted for cannabinoid analysis , hence a total of 90 plants (30 lines x 3 replications) (Bowen et al. 2021).Objective 3. Determine the effectiveness of organic insecticides in combination with biological control for suppression of hemp pests. Methods and feasibility. The experiments will be conducted on certified organic hemp fields at the CSU ARDEC Research Center over two growing seasons in 2024 and 2025. The experimental design will be a split plot design with three OMRI-approved insecticides (rosemary oil - TetraCURB Max, sulfur - MicroThiol Dispress, mineral oil - Suff-Oil) and untreated control as whole plot factors, and presence or absence of natural enemies (commercially purchased minute pirate bugs, predatory mites, and lacewing larvae will be released - 10 of each predator species per plant - two days after pest infestations) as the split plot factors. Each treatment combination will be replicated three times with 20 plants per plot (n=480). Insecticide treatments will be applied one month after transplanting (mid-July) and pest and natural enemy densities will be counted weekly thereafter for seven weeks. Arthropod sampling and counts will be conducted as described in Obj. 1 (Fig. 8). At maturity, plant biomass will be measured as the mass of the aboveground portion of all the plants in a plot. Plants will be cut at the soil surface and air-dried for a minimum of 30 days to determine yield.Objective 4: Develop outreach and educational materials that can be disseminated to hemp growers, industry agronomists, crop consultants, diagnostic labs, researchers and other stakeholders.Hemp Resource Center/ Hemp Insect Website and social media. The Hemp Resource Center/ Hemp Insect Website will serve as a centralized repository for all extension and outreach materials (posters, factsheets, videos, press releases, etc.) and to receive feedback from stakeholders. The website will be hosted at the CSU Hemp Resource Center website (http://hemp.agsci.colostate.edu/).Meetings. A second means of distributing information is through in-person meetings. The principal investigators will meet with Advisory Committee comprising of grower participants and industry representative twice a year to discuss research progress and outreach needs. The CSU Extension service workshops, annual field days organized as in-person and virtual format, the High Plains Organic Conference, pest management professionals meeting, CSU Agricultural Extension Service (AES) meetings will also be used as means to disseminate information. Researchers will present project findings at professional meetings such as Entomological Society of America (ESA) Pacific and North Central branch meetings and annual meetings.Publications. Lastly, information will be communicated via extension and scientific publications. Outreach materials will include state-specific extension factsheets, local newsletter articles, popular press articles, posters and presentations at regional and national meetings/field days will be deposited in the Hemp Resource Center website. At least one Extension factsheet will be developed for each of the research objective, and quarterly updates will be disseminated through press releases. Further, research findings will be published in peer-reviewed journals.