Source: COLORADO STATE UNIVERSITY submitted to NRP
BUILDING RESILIENT PEST MANAGEMENT STRATEGIES FOR ORGANIC HEMP SYSTEMS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
Reporting Frequency
Annual
Accession No.
1029067
Grant No.
2022-51300-38010
Cumulative Award Amt.
$749,999.00
Proposal No.
2022-04053
Multistate No.
(N/A)
Project Start Date
Sep 1, 2022
Project End Date
Aug 31, 2026
Grant Year
2022
Program Code
[113.A]- Organic Agriculture Research & Extension Initiative
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%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
21117301130100%
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.

Progress 09/01/22 to 08/31/23

Outputs
Target Audience:The target audience were hemp growers, industry agronomists, crop consultants, diagnostic labs, researchers, and other stakeholders. Outreach and education were fully integrated into our project at each step of development and execution of the objectives. Diverse and numerous multimedia and presentation strategies were used to reach our most diverse stakeholders. We targeted hemp producers, as well as crop advisors, crop consultants, extension personnel and hemp industry personnel (seed, genetics) with a variety of digital and traditional media. We used three main channels by which this information was disseminated: 1) CSU hemp entomology website (https://www.csuhempentomology.com/), 2) in-person meetings, and 3) publications. The CSU hemp entomology webiste serves as a centralized repository for all extension and outreach materials (posters, factsheets publications etc) and to receive feedback from stakeholders. We gave the following presentations: Schmidtbauer, M., Jessica, P., Szczepaniec, A., Uchanski, M.,Nachappa P. Don't panic, it's organic: Building resilient pest management strategies for organic hemp systems.Entomological Society of America Conference, 2024, Phoenix, AZ. Schmidtbauer, M., Jessica, P., Szczepaniec, A., Uchanski, M.,Nachappa P. Don't panic, it's organic: Building resilient pest management strategies for organic hemp systems. North Central Branch-Entomological Society of America Conference, 2024, Fort Collins, CO. Changes/Problems:We were awarded the grant on September 1, 2022, but we missed the 2022 field season. Hence, we requested a no-cost extension until August 31, 2026, so we can have three field seasons and time to analyze the data and write publications. There is no change in the scope of work, and we will complete all the goals and objectives delineated in the grant. What opportunities for training and professional development has the project provided?We trained one Postdoctoral Fellow, one PhDstudent, and one undergraduate student. The postdoctoral fellow has been trained in metabolomics, data analysis, grant and manuscript writing. The MS student has been trained in experimental design, insect identification, metabolomics,statistical analysis, and manuscript writing. The undergraduate student has been trained ininsect identification and data collection. How have the results been disseminated to communities of interest?The target audience were hemp growers, industry agronomists, crop consultants, diagnostic labs, researchers, and other stakeholders. Outreach and education were fully integrated into our project at each step of development and execution of the objectives. Diverse and numerous multimedia and presentation strategies were used to reach our most diverse stakeholders. We targeted hemp producers, as well as crop advisors, crop consultants, extension personnel and hemp industry personnel (seed, genetics) with a variety of digital and traditional media. We used three main channels by which this information was disseminated: 1) CSU hemp entomology website (https://www.csuhempentomology.com/), 2) in-person meetings, and 3) publications. The CSU hemp entomology webiste serves as a centralized repository for all extension and outreach materials (posters, factsheets publications etc) and to receive feedback from stakeholders. We gave the following presentations: Schmidtbauer, M., Jessica, P., Szczepaniec, A., Uchanski, M.,Nachappa P. Don't panic, it's organic: Building resilient pest management strategies for organic hemp systems. Entomological Society of America Conference, 2024, Phoenix, AZ. Schmidtbauer, M., Jessica, P., Szczepaniec, A., Uchanski, M.,Nachappa P. Don't panic, it's organic: Building resilient pest management strategies for organic hemp systems. North Central Branch-Entomological Society of America Conference, 2024, Fort Collins, CO. What do you plan to do during the next reporting period to accomplish the goals?We are in the midst of our third field season, during which we plan to repeat experiments related to Objective 3. We will also disseminate results through various avenues and publish results we have obtained so far.

Impacts
What was accomplished under these goals? Objective 1. In 2023 and 2024, pest and beneficial insect populations were significantly higher in the organic field. A total of 4,098 pests were recorded in the organic plots, compared to 2,583 in the conventional plots. Similarly, natural enemy abundance was elevated in the organic field, with 729 individuals observed versus 184 in the conventional field. Key pest taxa enriched in the organic system included plant bugs (Miridae) (42 ± 9, p = 0.002), leaf beetles (Chrysomelidae) (8 ± 2, p = 0.004), and owlet moths (Noctuidae) (4 ± 1, p = 0.003). Grasshoppers (Acrididae) (5 ± 1, p = 0.003) were the only pest taxon found in greater abundance in the conventional field. Prominent natural enemies in the organic field included minute pirate bugs (Anthocoridae) (27 ± 5, p < 0.0001), damsel bugs (Nabidae) (22 ± 5, p = 0.002), and lady beetles (Coccinellidae) (19 ± 3, p < 0.001). A similar pattern was observed in 2024, with 4,014 pest captures and 914 natural enemies recorded in the organic field. In contrast, both pest and beneficial insect counts declined in the conventional field, with only 370 of each observed. Cannabis aphids (Aphididae) (475 ± 170, p = 0.019), thrips (Thripidae) (33 ± 9, p = 0.007), and leaf beetles (Chrysomelidae) (21 ± 3, p < 0.001) were significantly more abundant in the organic field. Meanwhile, chalcid wasps (Chalcidoidea) (80 ± 14, p < 0.001), lady beetles (Coccinellidae) (4 ± 1, p < 0.001), green lacewings (Chrysopidae) (3 ± 1, p = 0.003), and syrphid flies (Syrphidae) (2 ± 1, p = 0.010) were also enriched in the organic field. Damsel bugs (Nabidae) (3 ± 1, p = 0.019) were the only beneficials found in greater numbers in the conventional field. Despite increased pest pressure, the organic field consistently produced greater yields across both years. Specifically, yield was assessed using three metrics: total biomass, flower, and fiber. In 2023, fiber yield was significantly greater in the organic field compared to the conventional field (54.6 ± 25.1, p = 0.034), while flower and total biomass were also higher, though not statistically significant. In 2024, all three yield metrics, total biomass (304.6 ± 116.7, p = 0.005), flower (210.5 ± 74.2, p = 0.003), and fiber (94.1 ± 46.5, p = 0.024), were significantly increased in the organic field relative to the conventional field. Phytohormone levels also differed between management systems. Phytohormone analysis was conducted at three developmental stages: vegetative, flowering, and harvest. Salicylic acid levels were elevated in the organic field during the vegetative timepoint (2347 ± 1273, p = 0.049). Abscisic acid was significantly increased in the organic field during both the flowering (25,467 ± 13,217, p = 0.043) and harvest timepoints (39,967 ± 13,763, p = 0.009). Dihydrophaseic acid was consistently higher in the organic field across all three timepoints: vegetative (140,733 ± 47,613, p = 0.008), flowering (25,383 ± 12,661, p = 0.038), and harvest (26,523 ± 9,092, p = 0.009), as was phosphatidic acid: vegetative (13,757 ± 5,638, p = 0.019), flowering (8,083 ± 2,560, p = 0.006), and harvest (6,960 ± 2,211, p = 0.006). In contrast, methyl jasmonic acid (121.7 ± 59.4, p = 0.035) was elevated in the conventional field during the vegetative stage. Additionally, 12-oxo-phytodienoic acid (20,982 ± 9,530, p = 0.028) and jasmonic acid (4,913 ± 2,009, p = 0.019) were significantly higher in the conventional field during flowering. Finally, 1-aminocyclopropane-1-carboxylic acid (673 ± 348, p = 0.042) was elevated in the conventional field at harvest. Phytohormone samples from the 2024 season have been submitted, and results are pending. In 2023, cannabinoid profiles showed limited variation between the two field treatments. Of the 18 cannabinoids analyzed, CBCO, CBCV, CBDV, CBL, CBN, CBT, and THCV were not detected. No significant differences were observed between fields in the levels of CBDA, CBD, Δ?-THCA, Δ?-THC, CBCA/CBLA, CBC, CBDVA, CBGA, CBNA, or THCVA. The only significant difference detected was for CBG (0.0033 ± 0.0016, p = 0.033), which was more abundant in the conventional field during the flowering timepoint. Cannabinoid samples from the 2024 season have been submitted, and results are pending. Preliminary results from the 2023 microbiome analysis suggest differences in microbial community composition between the organic and conventional fields. The conventional field exhibited significantly higher Shannon entropy (0.303 ± 0.110, p = 0.011) and observed amplicon sequence variants (ASV) (87 ± 36, p = 0.021), while Pielou's evenness did not differ between treatments. Despite higher alpha diversity in the conventional field, ANCOM (analysis of composition of microbiomes) indicated a greater abundance of nitrogen-fixing microbial taxa in the organic field, which may help explain the observed yield advantages. Microbiome samples from the 2024 season are scheduled for preparation and submission by the end of June 2025. Objective 2. In 2023, all experimental plots experienced comparable levels of cannabis aphid infestation during the flowering timepoint. While some genotypes showed clear resistance, others were severely impacted, with near-total mortality. Due to this uniform infestation pressure, aphid abundance alone was not a reliable indicator of plant quality. Instead, yield performance under infestation was used to identify genotypes with potential aphid resistance. For example, genotype 7550 consistently exhibited high biomass yield compared to genotypes 8259 (169.1±58.9, p= 0.045), 7619 (203.1±57, p=0.024), 4473 (182.9±61, p= 0.040), and 3583 (185.8±56.8, p= 0.031) to name a few. Although aphid counts varied by genotype, 7550 consistently showed lower infestation levels, consistently high biomass yield, and is a strong candidate for transcriptomic analysis to uncover mechanisms of insect resistance. Objective 3. In 2024, insecticide applications affected aphid and beneficial insect populations in the field. Field level aphid counts were recorded across nine sampling timepoints, with corresponding insect samples currently in cold storage. These samples are being processed and will provide greater resolution to support the field observations. Preliminary findings suggest that certain insecticides reduce cannabis aphid infestations while remaining compatible with beneficial insect releases. Although azadirachtin treatments (AzaGuard) appeared to increase overall yield, the increase was not statistically significant compared to the untreated control. Hemp flower samples have been submitted for cannabinoid profiling to evaluate whether pest pressure influences cannabinoid content, or if cannabinoid levels contribute to pest resistance. These trials are scheduled to be repeated in the summer of 2025. ?Objective 4. To foster engagement and promote hemp research, findings from these experiments have been shared at both national and regional Entomological Society of America meetings, as well as the Cannabis Research Conference. To broaden outreach to stakeholders, the Colorado State University Hemp Entomology website (https://www.csuhempentomology.com) was developed to serve as a central repository for research updates and extension materials.

Publications