ASHS 2025 Conference

Tomato fruit quality is directly related to marketability and consumer appeal. Unfortunately, consumers are increasingly discontent with the flavor and quality of the product they are purchasing and requesting tomatoes with improved flavor, aroma, texture, and appearance making it a high priority for breeding programs. Traditionally, the selection for fruit quality traits in breeding programs has been done using conventional phenotyping approaches, in which large populations need to be screened. Although this approach has resulted in the release of high quality-high yielding cultivars, it is very time-consuming, delaying cultivar release. An alternative approach to improve breeding efficiency involves the use of modern molecular breeding techniques. In this study, a diverse panel of 305 tomato genotypes, including 284 tomato breeding lines developed by Texas A

Septoria Leaf Spot (SLS), caused by the fungal pathogen Septoria lycopersici, is a highly destructive foliar disease affecting tomatoes. SLS is most severe in the Northeast USA and North Carolina during periods of high humidity and elevated temperatures, which can lead to catastrophic yield loss. No quantitative trait loci (QTL) associated with SLS resistance have been reported. Therefore, the objective of this study was to map the QTL related to SLS resistance in tomatoes. An F2:4 mapping population consisting of 189 individuals derived from NC123S (susceptible) x Wisconsin 55 (moderately resistant) was assessed under both field and greenhouse conditions through artificial inoculation with a spore concentration of 15.3 x 10^4/mL at the Mountain Horticultural Crops Research and Extension Center, Mills River, NC, and Mountain Research Station, Waynesville, NC. The population was genotyped using the SPET (single primer enrichment technology) Allegro targeted genotyping method. SPET-derived SNP (single nucleotide polymorphism) molecular markers were used to construct a linkage map spanning 3810.2 cM. QTL analysis identified 12 QTLs associated with SLS resistance, including two major effects and ten minor effects, typical for at least two environments identified across the genome, explaining phenotypic variation (R² value) ranging from 3.7% to 13.5%. These results demonstrate that the genetic control of SLS resistance is polygenic. This study may provide a foundation for understanding the genetics of SLS resistance and marker-assisted selection (MAS) for transferring SLS resistance genes into elite tomato breeding lines.

Drought is a major abiotic stressor that significantly reduces the growth and yield of tomato (Solanum lycopersicum L.). To mitigate its adverse effects, the development and utilization of drought-tolerant cultivars, combined with advanced breeding strategies, offer sustainable solutions. In this study, a total of 157 USDA tomato accessions were evaluated under controlled greenhouse conditions using a randomized complete block design with four replications, incorporating both a water-deficit treatment and a well-watered control group. The results identified ten accessions, including PI 487624, PI 127828, PI 379018, PI 365903, PI 390515, PI 390663, PI 128657, PI 266376, PI 126444, and PI 298933, as drought tolerant, with leaf wilting and leaf rolling scores of less than four. Broad-sense heritability estimates ranged from 50 percent to approximately 58 percent, indicating a moderate genetic influence on drought tolerance. Correlation analysis revealed strong positive associations ranging from 0.50 to 0.99 among leaf wilting, leaf rolling, plant freshness, leaf thickness, and SPAD chlorophyll content, while negative correlations ranging from -0.40 to -0.81 were observed for plant fresh weight, leaf thickness, Quantum yield of Photosystem II (Phi2), and SPAD chlorophyll content traits. These findings provide valuable insights into tomato breeding programs focused on improving drought resilience in elite cultivars. We plan to expand the evaluation to a broader set of accessions and employ genome-wide association studies and genomic prediction to identify single nucleotide polymorphism markers and candidate genes associated with drought tolerance. The integration of genome-wide association studies and genomic prediction will facilitate marker-assisted selection and genomic selection, improving the efficiency of breeding programs aimed at developing drought-resilient tomato cultivars.

Blossom-end rot (BER) is a physiological disorder in tomatoes that renders the fruit to be unmarketable. In tomato, BER initiates around 7-10 days post anthesis (DPA) at the distal end of the fruit as a water-soaked symptom that can progress into a necrotic lesion covering the entire fruit during development. Calcium deficiency in the distal end of the fruit is thought to trigger BER initiation. In this study, we have used near isogenic lines (NILs) that segregate for BER and harbors quantitative trait loci (QTLs) BER11.1 and BER11.2. Physiological characterization indicated lower calcium concentration and reduced number of vascular bundles in the distal inner and distal pericarp tissue in the susceptible fruit in comparison to the with resistant fruit. To further delineate the molecular mechanisms underlying BER development and to identify the potential candidate gene(s) underlying QTL BER11.1

Fresh market tomato (Solanum lycopersicum) is one of the most important vegetable crops in the US, but this labor-intensive industry faces severe labor shortages and rising production costs amid heavy competition from lower-cost imports. With labor accounting for over 30% of total production expenses, much of which is due to harvesting, the industry's long-term sustainability depends on developing more labor-efficient systems. Mechanical harvesting presents a promising solution, but tomato fruit are highly susceptible to bruising, a challenge that could be amplified by mechanized handling. Fruit firmness plays a crucial role in resistance to internal bruising, making it a key breeding target for improving harvest efficiency and post-harvest quality. The UF/IFAS tomato breeding program has developed tomato lines with traits beneficial for mechanical harvesting, including compact growth habit (CGH) and increased fruit firmness. To investigate the genetic basis of fruit firmness in CGH lines, bi-parental populations were developed from firm and soft inbred parents. Genome-wide association analysis identified multiple minor-effect QTLs, confirming the quantitative nature of this trait in the population. Variance component analysis revealed that fruit firmness is primarily controlled by additive genetic variance, suggesting a strong potential for improvement through selection with appropriate strategies such as genomic selection (GS), which has been successfully used to improve quantitative traits in many crop species. GS models were successfully trained to predict fruit firmness, demonstrating the feasibility of integrating GS into the UF/IFAS tomato breeding program. Model optimization, including adjustments to training population size, marker density, and the incorporation of significant QTLs as fixed effects, improved prediction accuracy and computational efficiency. This study confirms the presence of significant fruit firmness variability in UF/IFAS germplasm, supporting its use in breeding firmer CGH tomatoes suited for mechanical harvest. Future research will refine GS models by incorporating multi-trait and multi-environment analyses, leveraging variance-covariance relationships to enhance prediction accuracy and accelerate genetic gains.

Speed breeding is a technique that utilizes controlled environments and optimal lighting (photoperiod) conditions to accelerate germination, development, and maturity of plants. One of the major constraints for its adoption and implementation in vegetable breeding programs is the high cost associated with growth chambers. The objective of this study is to develop a Speed Breeding protocol for chile peppers using an improvised, low-cost growth chamber constructed using polyvinyl chloride (PVC) plastic, greenhouse film, mylar reflective film, full-spectrum and far-red light-emitting diode (LED) growth lights. Four C. annuum L. genotypes, namely, NuMex Lotalutein (a serrano type), NuMex Odyssey (New Mexican), NuMex Las Cruces (cayenne), and Early Jalapeno (jalapeno) were planted in two randomized flat trays, using SunGro propagation soil, and watered twice daily. After reaching the 2-3 leaf stage, the treatments (control and Speed Breeding, SB) were transplanted into 8” pots, incorporating sterilized and LM-AP soil mixtures. The control group was cultivated in standard greenhouse conditions for growing chile peppers, exposed to normal daylight intensity and duration, and an average temperature of 21°C and humidity of 40%. The chamber was also constructed in the same greenhouse. From weeks 1 to 5 after planting, the SB-treatment was subjected to 20h/4h light/dark conditions daily, and 9h/15h light/dark after week 5. Light intensity was increased by ~100 photosynthetic active radiation (PAR) weekly after week 5, from ~150 PAR to ~800 PAR. Data was recorded weekly to examine the effects of treatment on germination rate, plant size, leaf number and color, number of flowers, buds, and fruits, and days to flower and fruit. There were significant differences (Tukey HSD, P < 0.05) between treatments for germination rates, number of buds, fruits, leaves, and days to flowering. The SB-treated pepper plants exhibited faster and higher germination, darker green leaves, and a higher number of buds and fruits compared to the control. For instance, SB plants started flowering, on average, about 20 ± 5 days earlier, germinated 5 ± 1 days earlier, and had, on average, 15 ± 2 more buds than the control. Notably, all genotypes under the SB-treatment had at least one fully mature fruit ~106 days after sowing. These results suggest that, at minimal costs, there is a potential to achieve increased generation times to accelerate cultivar development and genetic improvement in chile peppers.

Watermelon is a preferred fruit in the Caribbean and all over the world and is the second most consumed cucurbit by harvest weight in the Virgin Islands after cucumber. While quality of water of watermelon is commonly judged by sweetness, the ratios of types of sugars are hardly considered. Watermelon is classified as one of the fruits with very high glycemic index, GI – the measure by which a dietary intake increases the blood sugar compared to pure glucose whose GI is 100. Watermelon is normally promoted as a highly nutritious as it is one of the best sources of potassium, but can be both a blessing and curse, especially for consumers with high blood sugar-related ailments. Here we report on preliminary efforts we are making to produce watermelons that have reduced GI. We are using hybridization as well as exploiting genotype-by-environment interactions to influence sugar composition in fleshy fruit tissues. We have obtained three hybrids that have at least 22% reduced glucose and at per brix compared to the parents. We are also testing a series of shadehouse systems, two of which show the potential to lower glucose ratio in the fruits. We hope to refine these methods and evaluate the watermelon lines for yield and sugar trait stability before recommending plant materials and production systems to interested farmers. Key words: Hybrids, sugar, glycemic index, genotype by environment, production system, sucrose, watermelon.

Effect of Microalgae Application on Yield and Nutrient Composition of Arugula Sam Pratt1*, Shivani Kathi1, Steve Phillips2, and Justin Moss1 1Department of Horticulture and Landscape Architecture, Oklahoma State University, Stillwater, OK, 74078 2Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK, 74078 *Presenting author- Samatha.pratt@okstate.edu Chlorella (Chlorella vulgaris) has been used as a biofertilizer in horticultural crop production in controlled environment production systems. However, research gaps exist in the application of chlorella biofertilizer in field-based production systems. The goal of this research is to assess the impact of microalgae biofertilizers on crop productivity and nutritional quality of arugula grown in open-field using certified naturally grown production practices. To understand the impact of microalgae biofertilizer on soil nutrient and organic matter content, soil testing was done before and after treatment. Treatments included 50% and 100% nitrogen fertilizer and chlorella applied through foliar, soil and foliar soil application. Chlorella application began a week after transplanting. Data was collected on number of leaves per throughout the study and fresh and dry weight at harvest. Plant samples were analyzed for nutrient composition of leafy greens (chlorophyll, carotenoids, and mineral nutrients composition). Results show that soil applied chlorella was more effective application method regarding the overall impact on yield. Continued research on the addition of Chlorella in crop production can offer additional nitrogen sources for low chemical input and organic based production systems.

Organic vegetable farmers use a wide variety of nitrogen (N) fertilizers from commercial products (made from animal and seed meals) to manures and composts. These organic N sources must undergo mineralization and nitrification to become plant available inorganic N (microbial processes). How much and when nitrogen becomes available can be highly variable dependent on product characteristics and local weather conditions, and this subsequent N availability can greatly impact yield. The objective of this study was to determine nitrogen mineralization, head timing, and overall yield from seven different organic fertilizer treatments on fall broccoli (Brassica oleracea ‘Castle Dome’). Studies were conducted over two years at the UGA Durham Horticulture Farm on certified organic land and organic fertilizers (with the exception of the control) were applied to provide a rate of 134 kg N ha-1. Fertilizers ranged from processed animal meals to composts and fresh poultry litter. Nitrogen mineralization was measured using in-situ soil cores and ranged from 0 (immobilization) to 100% of the N applied. Significant N was observed from the soil only treatment which provided on average 100 kg N ha-1 over the growing season. In both years, overall higher yields were observed with blood meal and lowest yields were observed with compost/control treatments. Fertilizer type impacted the timing of heading and overall harvest windows.

Nutrient and weed management are two of the biggest challenges in organic vegetable production systems. Anerobic soil disinfestation (ASD) is an effective method to manage the weeds and soil borne pathogens in organic production systems. In ASD, a carbon source is added to soil followed by watering to saturation and covering with plastic mulch to create anerobic soil conditions. Rendered animal and treated manure products have significant content of plant nutrients and carbon and can serve both as organic fertilizer and carbon source for ASD. A field experiment was conducted using three different carbon sources meat and bone meal (MBM; rendering product), MBM Sulfur and treated manure solids with objective to evaluate the effect of different carbon sources and their application rates on nutrient management and ASD in organic watermelon under traditional and novel charter next generation plastic mulch. We will be evaluating the treatment effect on soil cumulative anaerobicity, percent weed coverage, yellow nutsedge rhizome viability, plant vigor ratings, shoot and root biomass, periodic nutrient leaching, soil nitrogen and phosphorus content, plant tissue nutrient content (root and shoot), soil pH, soil C, N and P mineralization enzymes and soil microbial biomass. In results, MBM with sulfur at 150% recorded the highest cumulative anaerobicity and low weed coverage suggesting that it could be an excellent tool for soil nutrient management and weed control in organic production system.

This study presents the evaluation of ten organic cover crops on soil fertility and macronutrient accumulation within their biomass. Field trials were conducted at the organic farm of Tennessee State University using a randomized complete block design with four replications under National Organic Program (NOP) management practices. The cover crops assessed includes barley, crimson clover, daikon radish, field peas, hairy vetch, mammoth red clover, medium red clover, tillage radish, white clover, and winter rye. Each plot measured 16 ft x 7 ft within a whole plot size of 190 ft x 63 ft. Cover crops were sown using a seed drill, adhering to USDA and SARE recommended seed rates. Soil Samples were collected at a foot depth both before and after cover crops termination to analyze the variations in soil properties such as pH, phosphorus, potassium, calcium, magnesium, zinc, iron, manganese, boron, sodium, and organic matter. Aboveground biomass was clipped from 1ft2 quadrants across all replications, dried at 60oC for 72 hours. Samples were grinded to a fine powder using a 1100-watt Ninja blender and analyzed for nitrogen and carbon content using Near-Infrared Spectroscopy (NIRS). Results indicated that most of the cover crops increased soil organic matter, phosphorus, sodium, magnesium, and iron. In contrast, declines were observed in soil pH, potassium, manganese, calcium, boron, zinc. Significant differences were observed in the nitrogen and carbon accumulation among cover crops. Hairy vetch showed the highest nitrogen (4.24%) and carbon (46.62%) content, while barley and daikon radish had the lowest nitrogen (1.55%) and carbon (40.66%) content, respectively. The carbon to nitrogen (C:N) ratio ranged from 11:1 to 30.1:1, with legumes generally exhibiting lower ratios (11:1 to 15.3:1) demonstrating higher decomposition and quicker nutrient release. In contrast non-legumes had the higher ratios (25.4:1 to 30.1:1), suggesting slower nutrient release. These findings highlight the short-term impacts of different organic cover crops on soil fertility and nutrient cycling. The variation in macronutrient accumulation and C:N ratios provides practical insights for the growers in selecting appropriate cover crops to enhance soil health and support sustainable agricultural systems.

The increasing demand for sustainable agricultural practices has driven the adoption of organic farming and increased demand for organic transplants. However, transplant growth is often lower in organic fertilizers compared to conventional fertilizers. This is most likely caused by low nutrient availability in organic fertilizers. On the other hand, increasing organic application rates has the potential to induce salinity stress/toxicity. We hypothesize that biostimulants can complement organic fertilizers in crop production by enhancing nutrient uptake and increasing crop tolerance to abiotic stress and thus close the yield gap between organic and conventional fertilizers. In this study, we tested three biostimulants: humic acid and molasses (MicroLife Soil and Plant Energy) and two microbial based biostimulants with different beneficial microorganism populations (MicroGrow CM and MicroGrow Supreme). Four organic fertilizers were tested with biostimulants, two of which were animal-based fertilizers: Sustane (4-6-4, turkey manure) and Drammatic (2-4-1, derived from fish scrap) and two of which were plant-based fertilizers: Nature Safe (7-7-7, corn steep liquor) and Pre-Empt (fermented sugarcane molasses). After applying to peat-based substrate, we analyzed the leachate nutrient availability weekly. Both fertilizer and biostimulant affected available nutrient concentrations in substrate. Additionally, transplant performance was evaluated to determine the effect of biostimulant and organic fertilizer combination on transplant growth, mineral nutrition, and physiological responses. Transplant growth varied across the different combinations of biostimulants and organic fertilizers tested, suggesting potential interactions between these factors. Some biostimulant treatments, particularly in combination with specific organic fertilizers, showed a trend towards improved early growth compared to the organic fertilizers alone. These results showed synergistical effects between biostimulants and organic fertilizers, indicating the positive role of biostimulants in organic transplant production.

Increased concerns over the last several decades on environmental quality have stimulated farmers to accept organic farming as an alternative to inorganic agriculture. Muscadine (Vitis rotundifolia var. Summit) is native to the southeastern United States and has been cultivated for over 400 years. Muscadine and its products are highly nutritious and a good source of antioxidants and dietary fiber that have positive effects on health. Muscadine was grown on Memphis Silt Loam soil (Typic Hapludalph, silty, mixed, thermic). Three treatments of organic manures (cow-C; poultry-P; cow poultry-CP) with gypsum and pine mulch were applied in a CRD. Control received inorganic fertilizers and traditional cultural practices. Dolomitic lime was applied every 2 to 3 years to balance the soil pH of the soil and the pine needle was continuously applied as a thick mulch to bring down the soil pH to neutral and also to prevent moisture evaporation from basins where fresh animal waste was applied. This thick layer of pine needle mulch helped avoid irrigation even during the hottest summer. While strictly following the protocol, soil samples were collected and analyzed at Cornell Soil Health Lab, Cornell University, Ithaca, NY, after 17 years of continuous organic research with the same treatments. The experimental design for data analysis was a completely randomized design with three replications for each treatment. Leaf area index (LAI), percent canopy cover, stem diameter, and yield were higher in organic plants. There was no significant difference in diameter, length, and degree brix of the fruit. Soil compaction was always higher in control with lower soil moisture content and the compaction was lower in organic treatments due to higher level of organic matter content. Concentrations of nitrate-N and P were higher in the surface soil treated with organic manures, but there was no trend in N or P enrichment in the lower layers of the soil. A comprehensive assessment of soil health done by Cornell Soil Health Lab showed the following: physical aggregate stability 19.0 25, biological organic matter 4.0 85, biological ACE soil protein index 6.8 43, biological soil respiration 0.8 75, biological active carbon 747 90 and chemical soil pH 7.1 100 with an overall quality score of 72 (Excellent). The results suggest that the controlled application of animal and forest wastes in basins of fruit trees can be an agronomically and environmentally sound practice to increase yield and keep the soil and humans healthy.

Global olive oil production tripled over the past six decades to 2.76 million tons in the 2022/23 year. California is the largest producer of olive oil in the United States, and its planting is increasing at an estimated rate of 3000 acres per year. Most of the new plantings for oil in California are in hedgerows under intensive management either in a super high (SHD) or medium (MD) density systems. Of these plantings, an estimated ~80% is ‘Arbequina’, ~15% ‘Arbosana’, and ~5% ‘Koroneiki’. As expected, the industry is continuously searching for novel cultivars that can improve productivity, as well as extra virgin olive oil (EVOO) quality, thereby increasing  returns for their operation. With industry support, a trial was planted at the Wolfskill Experimental Orchard in Winters, CA in 2019 with the exception of ‘Lecciana’ which was planted in 2020. Four acres were planted at a SHD rate of of 620 trees per acre, with 5 feet between trees and 14 feet between rows. ‘Arbequina’, ‘Arbosana’, and ‘Koroneiki’ were planted alongside two new cultivars, ‘Lecciana’ (Olea europaea ‘Arbosana’ x ‘Leccino’) and ‘Sikitita’ (Olea europaea ‘Arbequina’ x ‘Picual’), and one numbered selection, Agromillora 9805-01. The orchard was planted with five complete replicates of the six cultivars, each cultivar row was randomized within each replicate. Seasonal and cumulative yield were measured from the 2021 through the 2024 growing seasons. Fruit weight, oil content, basal shoot prevalence, and maturity index were measured over the 2023 and 2024 growing seasons. The entire orchard was managed following industry agronomic practices for all replicates. During the four years ‘Koroneiki’ had the greatest cumulative yield on average, followed by ‘Arbequina’ and ‘Arbosana’, ‘Lecciana’, ‘9805-01’, and ‘Sikitita’ (16.60, 13.38, 13.37, 10.61, 8.17 and 7.76 tons per acre respectively). Alternate bearing behavior was more prevalent for ‘9805-01’ and ‘Sikitita’. Further, ‘Sikitita’ took an additional year to come into production. These results, alongside seasonal yield, oil content, basal shoot prevalence, and fruit weight, show why ‘Arbequina’, ‘Arbosana’, and ‘Koroneiki’ are the prevalent cultivars in California SHD plantings. In our trial, ‘Arbosana’ and ‘Koroneiki’ performed as well or better than ‘Arbequina’, but California growers have planted less of those two cultivars due to concerns with disease resistance and/or vigor management over time across California’s climatic conditions. Our research shows that further evaluation of novel cultivars is essential for a growing industry.

As nanoplastics become an increasing environmental and human health concern, greater understanding of their absorption by crop plants is vital. Many plant species, including lettuce, have been reported to transport nanoplastics from roots to leaves, but most research has not been conducted with crops grown in commercial production systems to harvestable size. Across two greenhouse experiments, we compared ‘Winter Density’ romaine lettuce grown with and without the addition of 10 mg.liter-1 yellow-green fluorescent-labeled 0.2 µm and 0.05 µm polystyrene nanoplastics (PSNP) added to municipal irrigation water in commercial-style hydroponic Nutrient Film Technique (NFT) systems. No difference was observed between lettuce grown with or without PSNPs based on plant width; shoot and root fresh and dry weights; number of true leaves; or chlorophyll content. Stomatal resistance of plants in both treatments was also not different and indicated very high transpiration rates that would support PSNP translocation to shoots. Fluorescence of shoots and roots from each treatment was evaluated via confocal microscopy. No PSNPs were found in the shoot tissue. In the roots, we observed PSNPs aggregated on the surface and possibly penetrated a maximum of 10 to 25 microns deep within outer root tissue. In root samples processed with acetone washes, no PSNPs were observed on or in root tissue by either TEM or confocal microscopy. As such, we found no evidence that 0.2 µm or 0.05 µm PSNPs are absorbed into the vascular system of hydroponically-grown lettuce plants and thus are not translocated to shoot tissue. These findings emphasize problems with current literature and the need for further research to investigate PSNP uptake by plants in realistic production systems.

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Food waste liquid anaerobic digestate (FWLAD) contains higher salt concentrations than synthetic fertilizers at comparable nutrient levels. As a result, plants may experience salt stress at optimal nutrient concentrations or nutrient deficiencies when electrical conductivity (EC) is reduced. Silicon (Si) has been shown to alleviate salt stress and promote plant growth under nutrient-limited conditions. This study investigated whether Si supplementation can mitigate salt stress under high EC and enhance growth under low EC when FWLAD is used to fertilize lettuce (Lactuca sativa ‘Muir’) transplants. Lettuce seeds were sown in either rockwool plugs or a 128-cell plug tray filled with a peat-based growing medium. One week after sowing, seedlings were sub-irrigated with one of nine nutrient solutions prepared from FWLAD. These solutions were adjusted to one of three target EC levels (1, 2, or 3 dS·m⁻¹) and amended with one of three Si treatments: (1) no Si (control, supplemented with 1.5 mM potassium sulfate to match potassium levels), (2) 1.5 mM lab-grade potassium silicate (prepared from silicic acid and potassium hydroxide), or (3) 1.5 mM commercial-grade potassium silicate (AGSIL16H, a commercially available product). Seedlings were grown indoors at 22 °C, with a photosynthetic photon flux density of 200 µmol·m⁻²·s⁻¹ and an 18-hour photoperiod, for a total of three weeks after sowing. For the control treatment without Si, leaf number, total leaf area, and shoot fresh mass were highest at EC 2, indicating that moderate EC promoted optimal growth. Compared to the control, supplementation with lab-grade potassium silicate increased leaf number, total leaf area, and shoot fresh mass by 16%, 63%, and 56% at EC 2, and by 69%, 423%, and 255% at EC 3 in rockwool, and by 10%, 10%, and 11% at EC 2, and by 19%, 42%, and 63% at EC 3 in growing medium. At EC 1, lab-grade potassium silicate had little to no effect on leaf area and shoot fresh mass in either substrate. Commercial-grade potassium silicate did not affect leaf number, leaf area, or shoot fresh mass at any EC. These results suggest that Si supplementation using lab-grade potassium silicate can improve lettuce seedling growth under high-EC conditions when fertilized with FWLAD, with more pronounced effects observed in rockwool compared to the growing medium.

Strawberries are the top consumed and produced berry in the United States. Demand for local and off-season availability has increased the production of strawberries in controlled environment agriculture (CEA). While production protocols exist for many leafy greens, limited information is available for emerging CEA crops such as strawberry. Optimizing carbon dioxide (CO2) concentrations for CEA strawberry production is of interest, given that previous research has shown increased yields and enhanced organoleptic properties of strawberries with CO2 enrichment. However, strawberry chemical composition varies depending on cultural practices, environmental conditions, and cultivar. Therefore, the objective of this research was to evaluate the impacts of CO2 enrichment on yield and fruit quality of everbearing strawberries in a controlled environment. Two strawberry cultivars (Fragaria ×ananassa ‘Albion’ and ‘Ozark Beauty’) were propagated from vegetative runners and grown in 2.7-L pots for eight weeks in walk-in growth chambers under either an ambient (450 μmol·mol–1) or enriched (900 μmol·mol–1) CO2 concentration. Temperature and relative humidity setpoints were 20/12 °C and 55/65% (day/night), respectively, with a photosynthetic photon flux density target of 348 µmol∙m–2∙s–1 (18-h photoperiod; daily light integral of 21 mol∙m–2∙d–1). Fruit mass, width, and count were collected weekly on all ripe berries and a USDA grade was assigned based on width and presence of damage. During the final harvest, fruit firmness and Brix:acid were measured to further assess fruit quality and samples were collected for a sensory evaluation. Total yield (grams/plant) of both cultivars was highest under CO2 enrichment. Specifically, total yield increased by 22% and 37% under CO2 enrichment compared to ambient for ‘Albion’ and ‘Ozark Beauty’, respectively. No quality differences (e.g., fruit firmness and Brix:acid) were observed between CO2 concentration treatments for either cultivar. These results were similar to sensory evaluations for rate-all-that-apply (RATA) and affective (9-point hedonic scale) tests (n=84), with little difference observed between CO2 concentration treatments for either cultivar. Participants rated ‘Albion’ higher in overall appearance and overall liking compared to ‘Ozark Beauty’, regardless of CO2 treatment. ‘Ozark Beauty’ consistently rated higher in fermented flavor. In summary, CO2 enrichment increased everbearing strawberry fruit production without negatively impacting berry flavor for these two cultivars. Outreach efforts have sought to disseminate these results and, through program evaluation, identify interest and potential barriers to crop diversification and adoption of CEA strawberry production in Denver, CO.

As the adoption of grafting technology is increasing among growers to manage soilborne diseases in watermelon production and new rootstocks are being developed, more research is needed to test different combinations of rootstocks and scions to identify growth differences that may be influenced by rootstock-scion interactions. In this greenhouse pot study, we examined the impact of the interspecific hybrid squash rootstock ‘Camelforce’ (Cucurbita maxima × C. moschata) and the wild watermelon rootstock ‘Carolina Strongback’ (Citrullus amarus) on the growth and development performance of two seedless watermelon scion cultivars with contrasting fruit maturity characteristics. Two weeks after seeding, early-maturing ‘Citation’ and late-maturing ‘Miramonte’ seedless watermelon plants were grafted onto each rootstock, respectively, with non-grafted scions and rootstocks as controls. The plants were arranged in a randomized complete block design with five replications and three plants per experimental unit. Non-grafted ‘Camelforce’ showed the longest primary vine, while ‘Miramonte’/‘Camelforce’ displayed significantly higher total vine length than other treatments. Non-grafted ‘Carolina Strongback’ exhibited significantly more leaves, followed by ‘Miramonte’/‘Camelforce’ and non-grafted ‘Miramonte’. ‘Camelforce’ also exhibited significantly greater above and below-ground dry weights, followed by ‘Miramonte’/‘Camel force’, although it did not differ from non-grafted ‘Miramonte’. The dry weights of ‘Citation’/‘Camelforce’ were significantly higher than non-grafted ‘Citation’. The above-ground dry weight of ‘Citation’/‘Carolina Strongback’ was significantly lower than all groups, except for non-grafted ‘Carolina Strongback’. Similarly, the below-ground dry weight of ‘Citation’/‘Carolina Strongback’ was significantly lower than treatments, except for ‘Miramonte’/‘Carolina Strongback’ and non-grafted ‘Carolina Strongback’. All treatments showed male and female flowers by week 3 after transplanting. Both non-grafted rootstocks showed more female flowers than non-grafted and grafted scions. At week 4 ‘Miramonte’/‘Carolina Strongback’ had more female flowers than all other treatments, while non-grafted ‘Camelforce’ exhibited the lowest. No difference in female flowers between the grafted and non-grafted scion groups was observed. Non-grafted scions exhibited more male flowers than the respective grafted plants by week 3. No differences were observed in male flowers except ‘Citation’/‘Carolina Strongback’ with fewer than grafted and non-grafted scions by week 4. Week 3 female flowers results suggest that grafting can significantly affect plant growth, but has a limited impact on flowering. The ‘Miramonte’/ ‘Camelforce’ group exhibited vigorous growth without significantly affecting flowering. Further research is necessary to explore how different types of rootstocks may impact fruit development of watermelon scions of varying fruit development characteristics in commercial production.

Coffee grounds are generated by home residents daily. The objective of this study is to use an accelerated home food scrap composter to encourage residents to reduce waste volume and weight and provide garden compost to produce garden produce and flowers. Two accelerated composters (Lomi and Vego) were evaluated both for their compost soil health, physical and chemical properties after processing the spent coffee grounds. Lomi processed food for 24h only and the Vego composter for 1, 5, and 10 days. Compost volume and weight increased as days of composting increased. Compost health, nutrients, pH, C/N Ratio were suitable for a horticultural growing amendment. Physical components were within normal parameters for a soil substrate. Finer particles were increased with greater days of composting as expected. Plant growth differences were measured. Compost incorporated at 10 % v/v increased petunia biomass. Accelerated composters reduced volume and weight of food scrapes while providing essential plant nutrients.

The probiotic strain Lactobacillus plantarum ATCC 8014 is an ideal model for studying prebiotic interactions primarily due to its demonstrated ability to metabolize a wide range of prebiotic compounds. Hence, this study examines the potential synergistic effects of limonoid glucoside (LG), a citrus-derived phytochemical, in combination with dietary fibers on growth kinetics, amino acid metabolism, biofilm formation, and bacterial performance under salt stress conditions. Treatments included de Man, Rogosa, and Sharpe Agar (MRS) media supplemented with various individual and combinations of LG and dietary fibers, pectin (PEC), and inulin (IN). Individual treatments contained 1 mg/mL of LG, PEC, and IN, while combination treatments used a 0.5 mg/mL concentration of each component. Among the tested NaCl salt concentrations of 1%, 2%, and 4%, concentrations below 2% showed sustained bacterial growth for all the combinations (LG: PEC/IN). Salt concentrations at 4 % negatively impacted the bacterial growth in all the treatments and control; however, an exponential rise in growth was observed after the 18th hour of incubation in PEC: LG, indicating a delayed lag phase. Such a pattern of growth at high salt stress possibly indicates that the co-treatment with LG and PEC could potentially maintain growth, help conserve energy demands, and display osmoregulatory effects to overcome salt stress. Additionally, differences in cell surface hydrophobicity between treatments suggest improved bacterial adhesion and biofilm formation. The LG treatment resulted in significantly increased hydrophobicity, indicating enhanced adhesion potential. IN, LG: PEC/IN treatments showed moderate hydrophobicity, comparable to the MRS control, while PEC exhibited the least. These findings are important, as higher cell surface hydrophobicity is crucial for providing protection against environmental stressors and supporting healthy microbial interactions. Amino acid profiling showed treatment-dependent changes, suggesting that LG and PEC/IN combinations affect amino acid metabolism significantly. Additionally, digested samples exhibited enhanced radical scavenging, indicating potential antioxidative synergy between digested LG and dietary fibers. By analyzing the effects of limonoid glucosides in combination with dietary fibers, this study highlights the potential synergistic benefits of these compounds in enhancing their functional properties and supporting a healthy gut microbiome.

While approximately 80 to 90% of the sprinkler-applied water to a strawberry crop is lost through runoff, deep percolation and evaporation, all the strawberry fields in Ventura County are still irrigated with overhead sprinklers during crop establishment. Even though water use-efficiency for the in-season irrigation is on average high, the escalating regulatory pressure to achieve sustainable groundwater use in California, and therefore limiting water availability, will demand further efficiency. This study quantified differences in water use, yield, canopy coverage and root depth between drip tape (DT) and micro-sprinkler (MS) irrigation during crop establishment at a commercial field located in Oxnard, CA during the 2023-2024 and 2024-2025 growing seasons. This abstract shares the results of the second season. The treatments were applied during the first 42 days after planting, after which drip tape became the only irrigation method. The irrigation scheduling of the MS treatment was defined by the irrigator (grower standard), while the DT irrigation was guided by tensiometers and field observations. All other production practices remained the same. Each treatment was replicated four times in a randomized complete block design, with an area of 0.15 acre per plot (7 beds of 175ft long). Total water use during establishment was 74.4% greater for the MS treatment compared to DT (5.8 and 3.4 acre-in, respectively). Marketable yield up to March 31 was very similar between treatments (19,268 and 19,420 lb/acre for DT and MS, respectively) and not statistically significant (p-value = 0.9517). Although not statistically significant, canopy cover MS was 9 and 11% greater at 1 month and 3 months after planting, respectively. Root depth measured at 1 month after planting was very similar and not statistically different (p-value = 0.9496).

Walnut is currently grown on over 400 thousand acres in California with the majority of production in the Northern San Joaquin Valley (NSJV). The recurring droughts and climate change in California will likely increase the uncertainty in water supply to walnuts and other specialty crops. Site-specific irrigation is critical to cope with these challenges. Knowing the water use of walnuts is crucial in optimizing irrigation management since it affects nut quality, and productivity. Unlike traditional methods, which are often limited by spatial coverage, high costs, and less precise crop coefficient values, satellite remote sensing offers a cost-effective, widely accessible solution. It enables large-scale evapotranspiration (ET) estimation with increasing adoption in irrigated agriculture, providing a valuable tool for water management. This study compares OpenET models, an open-source database providing ET estimates, against commercial in-situ surface renewal ET sensor. Utilizing OpenET platform provides a good opportunity for growers to improve water use efficiency. Such improvements could lead to the adoption of publicly available irrigation management tools and ensure healthier tree development, better resource utilization, and more resilient orchards in the face of climate change. Based on the data of 2024 season, the Satellite Irrigation Management Support (SIMS) model had the highest accuracy in estimating actual ET when compared to measurements from a commercial in-situ surface renewal system in the orchard, with a mean percent error (MPE) of -18.45%, and R² and mean absolute error (MAE) values of 0.88 and 0.03 inches/d⁻¹, respectively, followed by the Ensemble model. In contrast, the SSEBop model showed the lowest correlation with ETa, with an R² of 0.77 and a relatively high MAE of 0.06 inches, indicating a higher level of uncertainty in its estimates which could potentially lead to over-irrigation if adopted without correction. Based on these findings, growers can confidently incorporate the OpenET SIMS model into their irrigation scheduling, ultimately enhancing water use efficiency. However, further validation through replication over a second year and across multiple sites is essential to substantiate these findings.

Water scarcity is one of the major challenges facing the agricultural industry, necessitating the use of treated wastewater for irrigation purposes. However, not all crops can effectively utilize this water, as it may have negative effects on plant growth, including disruptions in nutrient uptake and photosynthesis. This study aimed to evaluate the effects of treated wastewater on the growth of rose-scented geranium (Pelargonium graveolens) and English lavender (Lavandula angustifolia). The experiment was conducted between 2022 and 2023 at the University of Fort Hare, Dikeni, South Africa. Two harvests were carried out in May 2023 (Harvest 1) and October 2023 (Harvest 2). Five irrigation treatments were applied to both geranium and lavender plants, consisting of treated wastewater from Dikeni town mixed with tap water at varying proportions: 0%, 25%, 50%, 75%, and 100% (v/v). Water and soil used were tested for nutritional composition. Treatments commenced four weeks after transplanting from cuttings, and the experiment followed a completely randomized block design with four replications across four blocks. The results showed no treatment differences in stem diameter, number of shoots, or plant height across treatments for both plant species during the two harvesting seasons. However, English lavender plants irrigated with 25% wastewater exhibited a slight increase in plant height at week 11, while geranium plants treated with 75% wastewater showed an increased plant height from week 5 until harvest at week 11. Additionally, plants receiving the 25% wastewater treatment produced the highest number of shoots from week 8 to week 11. These findings suggest that treated wastewater, both in its diluted and undiluted form, did not adversely affect plant growth. Therefore, it has the potential to serve as an alternative water and nutrients source for geranium and lavender plants, which farmers could utilize in collaboration with local municipalities to mitigate water scarcity challenges. However, further studies, particularly under open-field conditions, are needed to validate these results.

Runoff containing excess nitrogen (N) and phosphorus (P) is detrimental to environmental and human health. Bioreactors are biological treatment systems that can be used to combat these problems, which often consist of a lined trench filled with a carbon-rich media (often woodchips) to promote biological remediation through denitrification and other processes. Various carbon-rich organic materials, such as woodchips and sugarcane bagasse (a byproduct of sugarcane production), can be used to fuel biological processes, whereas inorganic materials, such as expanded shale, can provide binding sites for P adsorption as well as physical stability within medias. Raingarden installations utilize similar concepts for trapping runoff water and remediating contaminants; however, the inclusion of ornamental plants provides aesthetic appeal, an important consideration in urban and suburban areas. Seven unique medias were evaluated to determine potential to a.) remediate N and P from runoff and b.) support plant life. An aged pine bark/sand media commonly used for landscape beds (bed mix; BM) served as the control. Organic carbon sources (woodchips (WC) and sugarcane bagasse (SB) to support bacterial communities) and several inorganic materials (including expanded shale (S) and activated aluminum (AA) to bind P) were blended with BM to provide potential enhancement of nutrient removal capabilities. Media blends were homogenized by hand before being transferred into media containers (MC; 2.36 L of substrate per container), wherein Hibiscus moscheutos ‘Luna Pink Swirl’ seedlings were transplanted. Pots were placed within plastic containers (leachate containers (LC)), which served as a collection receptacle for leachate. Simulated runoff water containing N and P was prepared and applied to each replicate, after which leachate was analyzed and collected as sub-samples. Simulated runoff applications were limited in the initial phase of the study (one application per week; three total) and intensified in the final phase (three applications per week; nine total), with all leachate volumes collected between applications. Health and growth of Hibiscus was assessed via SPAD readings, growth index, and destructive harvest at the termination of the study. While the growth of all Hibiscus replicates was generally equivalent between treatments, it was observed that BM amended with SB produced more shoot biomass. Additionally, leachate nutrient content and water chemistry dynamics were influenced by several of the investigated amendments.

Green infrastructures, when implemented, need to consider the specifics of the local area and climate. The semi-arid climate along Colorado’s front range creates a challenge for plants in green infrastructure systems such as bioretention facilities and green roofs. These plants experience inundation and fast infiltration during rain events and long periods of hot and dry conditions between storms. To accommodate these periods of inundation and drought, Colorado native plants were evaluated due to their adaptation to the challenging conditions that occur in green infrastructure. The experiments in this study are intended to build upon existing work performed by our collaborators and funders Mile High Flood District, the City and County of Denver, and Colorado State University. We aim to improve green infrastructure facility design by using new bioretention media mixes, amended native soils with 5% compost (SSC) and amended native soils with biochar and zeolite (SBZ), green roof components/systems, new plant growth and establishment strategies, and lower irrigation regimes. In 2023 and 2024, data on plant survivability were collected from the bioretention facilities and the green roofs using 100 containerized and bare-root plants. The five native Colorado species selected were Agastache rupestris, Liatris ligulistylis, Amorpha canescens, Ratibida pinnata, and Schizachyrium scoparium. L. ligulistylis, in container, had a higher survival rate after one year on the green roof, on the other hand, it had a low survival rate after a year in the bioretention facilities. The bare-root L. ligulistylis had a higher survival rate, especially in the SSC media. A. canescens, bare-root, had a higher survival rate in the SSC media, while only 25% survived in the SBZ media. All other species overwintered and grew larger the second year on the green roof and bioretention facilities. The Colorado native plants tolerated challenging conditions better than the nonnative plants in the surrounding area.

Understanding the partitioning of evapotranspiration (ET) into soil evaporation and plant transpiration is critical for improving irrigation management in young orchards with limited canopy cover. This study focuses on partitioning ET in a 4-year-old drip irrigated pistachio orchard located in the Mesilla Valley, Southern New Mexico, using the Conditional Eddy Covariance (CEC) method. The orchard is equipped with a high-frequency eddy covariance system along with sensors to make meteorological measurements. The CEC approach was applied to identify and isolate flux contributions under specific atmospheric conditions, thereby separating transpiration-driven and evaporation-driven fluxes. The CEC separates fluxes using conditional sampling based on the hypothesis that when transpiration is dominant, CO₂ and H₂O fluxes should be highly correlated. Preliminary results show that the total ET values measured from June to August varied between 1.5 and 4.5 mm/day, with about 20% contributed through transpiration from the plants in the year 2024.

Lettuce (Lactuca sativa) is a key winter vegetable with significant consumptive water use in the Lower Colorado River Basin, especially in Yuma, AZ. Generally, lettuce requires about 300 – 400 mm to produce a desirable crop, which can vary significantly depending on irrigation method, soil type, field slope, temperatures, and planting window. However, the magnitude of the quantified differences in seasonal evapotranspiration and crop water productivity among different irrigation scheduling strategies under the subsurface drip irrigation method for organic vs. conventional iceberg lettuce production systems has not been sufficiently investigated. Field experiments were conducted in the fall 2024 growing season at the Valley Research Center at the University of Arizona Yuma Agricultural Center, Yuma, Arizona. This project was conducted in a one-acre field (half-acre organic field and the other half conventional field) under the subsurface drip irrigation method with two irrigation scheduling strategies (sensor-based irrigation (SI) and traditional irrigation (TI) based on growers' standard decision basis that is common in the Yuma area. The field was planted with the iceberg lettuce variety SVLD0023 on October 29th, 2024, on Gadsden clay loam soil. The fertilizer treatments imposed included (1) organic fertilizer, (2) combined biostimulant and organic fertilizer in an organic lettuce field, (3) nitrogen, and (4) combined biostimulant and nitrogen in a conventional lettuce field. Each treatment was replicated three times within each experimental block. Each experimental unit had three beds, and each bed was approximately 120 feet long and 3.5 feet wide, with a randomized complete block design. The objectives of this project include: (1) quantify and compare the seasonal iceberg lettuce evapotranspiration between organic and conventional iceberg lettuce production systems, (2) measure and compare the crop water productivity, and irrigation water use efficiency between two irrigation scheduling strategies for organic and conventional iceberg lettuce production systems, and (3) quantify and compare improvements in soil water retention under the combined application of biostimulant and organic fertilizers in organic lettuce versus the combined application of biostimulant and nitrogen in conventional lettuce. Data collection is currently in progress and will be analyzed in a manner consistent with the experimental design and the objectives of the study. Results will be presented with preliminary conclusions and directions for further research.

Many types of mulch have been shown to reduce weed growth in container crops. In the past, mulch use in nurseries was not as feasible due to its high cost, but as costs of hand weeding increase, labor shortages become more severe, and environmental awareness rises, utilization of mulch has become more popular in recent years. Parboiled rice hulls are a waste product of the rice industry and are dry rice husks removed from rice grains. They are light weight, hydrophobic and make for an ideal mulch choice in container nursery production and have been previously evaluated for use as a weed management tool in container nurseries. However, research was typically conducted on a limited number of species and studies were performed in greenhouses or other protected structures. The objective of this research was to evaluate rice hulls for control of five common nursery species in an outdoor environment in Florida during the summer season. Nursery pots (1.7 L) were filled with a standard pinebark based potting soil and amended with standard control release fertilizers via incorporation. Upon filling, pots received one of three levels of rice hulls, 0 cm or the non-treated control, 1.3 cm, or 2.5 cm. To test efficacy, approximately 30 seeds of crabgrass (Digitaria sanguinalis), doveweed (Murdannia nudiflora), longstalk Phyllanthus (Phyllanthus tenellus), spotted spurge (Euphorbia maculata), or eclipta (Eclipta prostrata) were sown either above or below the rice hull mulch layers mentioned above. Data collected included weed coverage ratings (0 to 100%) at 4, 6, 8, 10, and 12 weeks after planting (WAP) and shoot dry weights at 12 WAP. Few differences were observed among the different depths of mulch when seeds were placed below. For seeds placed on top of the mulch, the higher 2.5 cm depth generally provided greater control. For all 5 weed species, control significantly increased when seeds were placed on top of the mulch compared to seeds beneath the mulch layer. Control, as measured by a percent reduction in shoot weight compared to the non-mulched control, ranged from 80 to 100% for seeds placed on top compared with decreases of 0 to 40% when seeds were placed below mulch. Overall, data suggest that because rice hulls are more effective on weed seeds placed on top of the mulch layer, growers would likely see increased efficacy when mulching as soon as possible after potting.

Elevated temperatures can intensify weed issues by accelerating weed growth and germination, especially for C4 species, due to their heat tolerance and efficient carbon fixations, making their control more challenging. Temperature also influences herbicide absorption, translocation, and metabolism. Large crabgrass (Digitaria sanguinalis), a highly problematic C4 weed, poses a significant threat to nursery and field-grown ornamentals under these conditions. This study aims to evaluate the efficacy of postemergence herbicides at different rates (0.5X, 1X, 2X) under normal and elevated temperatures for managing large crabgrass in ornamental production. Experiments were conducted in summer and fall 2024 using a growth chamber and an open hoop house setup. Large crabgrass seeds were sown in pots filled with standard substrate, irrigated, and placed in separate growth chambers where temperatures were maintained at normal (22–28°C) and at 2-5°C above the species’ optimum range (28-34°C). Once weeds reached the 3–6 leaf stage, they were transferred to an open hoop house for herbicide application. Postemergence herbicides such as topramezone and glyphosate were applied at 0.5X, 1X, and 2X rates using a CO₂ backpack sprayer. After the restricted entry interval, treated weeds were placed back to their respective growth chambers and maintained there for four weeks. A control treatment without herbicide application was maintained in both growth chambers. Weed control ratings were visually assessed at 1, 2, 3, and 4 weeks after treatment (WAT) using a 0–10 scale, where 0 = no control (green foliage, upright growth, no damage) and 10 = complete plant death (dark brown foliage, no green tissue, collapsed structure)). At 4 WAT, all weeds were harvested, and dry weight of aboveground parts of weed was recorded. The experiment followed a completely randomized design with eight replications per treatment and was repeated twice. Data were analyzed using ANOVA in SAS 9.4, and treatment means were separated using Fisher’s LSD test. The results showed that at 4 WAT glyphosate weed control efficacy at normal temperature was 88% which reduced to 73% under elevated temperature condition. Whereas the high temperature increased topramezone efficacy by 10%. The lowest amount of weed dry weight was observed at 2X rates in high temperature conditions, but no difference was observed among rates at normal temperature. Hence it can be concluded that with an increase in temperature, higher rates of the tested herbicides will be required for effective weed management in ornamentals.

Intensive cultivation in high tunnel production systems is leading to the emergence of soilborne pest and pathogen issues which over time can compromise crop productivity and profitability. Growers facing such challenges are in search of sustainable and effective solutions capable of suppressing soilborne pests and pathogens while preserving soil health. Anaerobic soil disinfestation (ASD) is a broad-spectrum pre-planting biological approach proposed for the management of soilborne issues affecting high-value specialty crops. ASD is applied by incorporating in the soil readily labile organic amendments as a carbon (C) source, tarping the soil with an impermeable film, and irrigating the soil to saturation. Although ASD already proved to be effective against a range of soilborne pests and pathogens across different US regions, crops, and production systems, its adoption at commercial scale remains relatively limited. Factors hindering the adoption of ASD include application cost, complexity of microbial driven processes, and lack of knowledge of the method, its implementation steps, and its efficacy and benefits. Capitalizing on over six years of research aimed at optimizing the ASD application method and its integration in high tunnel production systems in Pennsylvania, a series of on-farm ASD applications were conducted over the 2023 and 2024 growing season with the purpose of demonstrating the technology and let growers evaluate first-hand its viability and efficacy. The on-farm trials were conducted on selected farms growing vegetables and small-berries in high tunnels and employing both conventional and organic production methods. Raised-bed and broadcast application were tested along with the use of clear and black film. Wheat middlings alone or in combination with feed-grade sugarcane molasses were tested as C sources testing different soil incorporation equipment and methods. Depending on the specific crop system, and the grower planting schedule, ASD was applied between the end of the Spring (before a late high tunnel crop planting) and mid-October (after an early high tunnel crop). Parameters measured included soil redox potential, temperature, pH, electrical conductivity and mineral nitrogen. The level of anaerobiosis achieved varied depending on the amount of labile carbon applied, the type of tarp used, and the temperature levels achieved. High levels of cumulative soil redox potential were achieved and the use of clear film allowed to achieve relatively higher soil temperatures and cumulative redox potential levels in most on-farm applications. Additional demonstration efforts are needed to facilitate the adoption of ASD and demonstrate its efficacy.

Organic farming with its reliance on natural fertilizers, cover cropping, and crop rotation, presents a sustainable approach to food production. However, a significant challenge in organic production is insect and disease management. Organic insecticides often have limited efficacy, are expensive, and require repeated applications. Mesotunnels, medium-sized (36-40 inches tall) tunnels covered with insect netting, have emerged as a pest management tool for organic vegetable growers. This study evaluated the effectiveness of mesotunnel and low tunnel systems for pest management and season extension in organic Chinese cabbage (cultivar ‘Minuet’) production. The first season of this two-year study was conducted in Fall 2024 on certified organic land at Iowa State University Horticulture Research Station, Ames, IA. The experiment was set up as a randomized complete block design with four replications and following treatments: i) 85 g ExcludeNet insect netting, ii) 0.55 oz Agribon row cover, iii) 85 g ExcludeNet insect netting + OMRI-listed insecticide iv) OMRI-listed insecticide, and v) an untreated control, uncovered with no insecticide. Weekly pest surveillance focused on Brassica insect pests such as aphids, loopers, harlequin bugs, flea beetles, and their damage was recorded. Hobo data loggers recorded variations in light intensity, air and soil temperature, and relative humidity to observe microclimate variations in each treatment. At harvest, yield data was categorized as marketable or nonmarketable and graded according to USDA commercial standards. Among all treatments, the highest marketable produce was recorded in ExcludeNet + OMRI-listed insecticide treatment (42%), followed by Agribon row cover (31%) and the lowest in OMRI-listed insecticide (15%) during the first harvest. The earlier maturity in these treatments was likely due to warmer temperatures and improved humidity regulation under the tunnels. The insect abundance and their damage on leaves was significantly lower in ExcludeNet & ExcludeNet + OMRI-listed insecticide treatment. Integrating netting and row covers with limited use of organic insecticides provided the highest pest suppression, suggesting that physical barriers can effectively optimize pest management and enhance marketability in organic vegetable production systems. Findings from this study will inform growers and the research community about the feasibility of insect nettings as a sustainable pest management tool in organic specialty crop systems.

Sunn hemp (SH, Crotalaria juncea L.) is used in Florida strawberry production as an off-season summer legume cover crop to provide agroecosystem services such as weed and plant-parasitic nematode (PPN) suppression. Bicultures of SH with sorghum-sudangrass (SS) (Sorghum bicolor Moench × S. sudanense [Piper] Stapf) are of interest to reduce the cost of SH use. Our study objective was to determine whether bicultures retain the weed and PPN suppression benefits provided by SH grown in monoculture. A replacement series experiment was conducted in summer 2022 and repeated in 2023 in north-central Florida in a PPN-infested field. A factorial treatment arrangement of five SH:SS biculture proportions (100:0, 75:25, 50:50, 25:75, and 0:100) and three seeding rates (20, 40, and 60 lb/acre) were evaluated in a randomized complete block design with four replications. A no-cover crop, weedy control was also included in each block. Data were collected on cover crop biomass and carbon: nitrogen ratio (C:N), weed density, weed biomass, and PPN populations at eight weeks after planting. Bicultures consistently produced higher total cover crop biomass than the SH monoculture. Bicultures were as effective as the SH monoculture in reducing total weed density and resulted in either lower or equivalent total weed biomass. Averaged over year, only the 60 lb/acre seeding rate had a lower total weed density than the 20 lb/acre rate. In 2022, both the 40 and 60 lb/acre seeding rates resulted in lower weed biomass than the 20 lb/acre rate, while seeding rate had no significant effect on total weed biomass in 2023. Root-knot nematode populations in both years and sting nematode populations in 2022 were detected at levels too low for analysis. However, in 2023, the lowest and highest sting nematode populations occurred with the SH and SS monocultures, respectively; and sting nematode populations increased as the proportion of SS in the bicultures increased. Bicultures with ≤50% SS had significantly higher sting nematode populations than the weedy control. An increase in C:N was observed as SS proportion in bicultures increased. Thus, we conclude that SH/SS bicultures maintain the weed biomass suppression benefits of SH monocultures while increasing cover crop biomass. However, bicultures may lead to higher sting nematode populations, which will be of concern in organic strawberry production where soil fumigation is not permitted. Growers will also need to consider the effects of the higher C:N ratio of biculture residue on nitrogen fertilizer immobilization.

Management of plant parasitic nematodes (PPNs), soil-borne diseases, and weeds in the strawberry industry is fundamental for every North Carolina grower, to achieve a successful production season. The prohibition of methyl bromide (MBr) in 2005 caused significant challenges for growers leading to the search for new and efficient strategies to suppress and control the impact of pests and diseases that affect strawberry growers. Hence, the objective of this project was to evaluate alternative fumigation strategies combined with new bed architectures for the control of soil-borne pests in strawberry production. Two experiments were conducted in North Carolina where, compact beds (24 inches wide by 12 inches tall) were compared to traditional North Carolina strawberry beds (30 inches wide by 6 inches tall). Both bed architecture designs were fumigated with either shank or drip-applied fumigants (Pic-Clor 60 and Pic-Clor 60 EC, respectively), with and without the inclusion of a soil surfactant for the drip fumigation treatments. In both studies, we measured strawberry plant biomass, volumetric water content in multiple points of the planting beds, plant parasitic nematodes (PPNs) and weed pressure before and after fumigation, plant reflectance indexes, bed compaction, and crop yield. Post-treatment results demonstrated that compact beds with both shank and drip-applied fumigants achieved comparable control of weeds and PPNs to traditional beds with shank fumigation. Bed compaction measures indicated that compact bed treatments present less compaction at 4-, 8- and 12-inch depths compared to the higher compaction observed in North Carolina’s traditional strawberry beds.

Minnesota (MN) in the US ranks 2nd for corn silage production and 3rd for soybean production. Studies have shown that off-target movement (drift) from an unshielded sprayer, in row crops, can range from 1 to 16% of the target dose; however, boom height and wind can double or triple these doses. Pre-study 37 pesticide residue tests were conducted in five Minnesota nurseries in 2018. Nine different herbicides were detected in the 37 tests. Glyphosate (sold as Roundup Power Max 32% glyphosate) became the focus of 2019 studies, conducted at concentrations of 0, 6, 18 and 54% for glyphosate as drift events. Relating ppm’s disclosed in laboratory analyte foliar residue samples collected by various state agriculture departments after drift events to injury symptom, development, and growth reduction or time after application have ever been conducted for nursery crops. From personal communication with nursery owners experiencing neighbor’s drift event (MD; KY, OH, MI, FL) the average time from the drift event to recognizing problems, and sample collection is six weeks (6 weeks after drift event) (6 WADE). Slower metabolism of glyphosate at higher residues, explained our finding that the largest residues were detected in all, but one species/ treatments used with glyphosate, versus three other herbicides examined or in combinations. Higher residues meaning higher injury, does not occur with glyphosate. Potentially high residues mean slow metabolism for glyphosate, and thus less injury. In five cases glyphosate applied alone had no impact on growth measured as caliper over the season, even though glyphosate had the highest residue in three of the five. In only one case was caliper growth reduction highest with glyphosate (Syringa 18%) over the entire study. In terms of phytotoxicity rating, glyphosate caused no commercially unacceptable injury in four cases. Residues increased with all rates on the three species evaluated between 3 DADE and 6 WADE. With Acer freemanii and Tilia cordata residue levels declined slightly between 6 WADE to 14 WADE with all rates. Only, Syringa reticulata showed an increase in foliar residues between 6 WADE to 14 WADE. Since carry over injury the next year (or three) is a concern with all glyphosate applications to perennial plants, all trees were observed in 2020. None were commercially acceptable and in severe decline (regardless of rate) in spring 2020, only 6% glyphosate on Syringa survived to the fall , and by spring 2021 were dead.