Nursery crops are commonly propagated from stem cuttings rooted in small-diameter containers, but weed infestations can reduce crop quality and be transferred into the production cycle. Preemergence herbicides are not labeled for use in cutting propagation, yet several products may be safe and viable alternatives to hand-weeding, which is costly and time-consuming. Optimizing the proper time for applying preemergence herbicides would provide propagators with more weed management tools. Our study (2020 and 2021) evaluated preemergence herbicide (isoxaben, isoxaben + dithiopyr, and oxyfluorfen + oxadiazon) and application timing (before, at, and after sticking cuttings) compared with an untreated control on the rooting and growth of cuttings from four ornamental plant species [butterfly bush ( Buddleja davidii ‘Nanho Blue’), hydrangea ( Hydrangea paniculata ‘Limelight’), holly ( Ilex cornuta ‘Dwarf Burford’), and crape myrtle ( Lagerstroemia indica ‘Catawba’)]. Application timing did not affect root or shoot biomass of the tested plant species except for isoxaben + dithiopyr applied at and after sticking on crape myrtle (in 2021). Isoxaben and isoxaben + dithiopyr were safe on all the other plant species except butterfly bush, for which neither product is labeled for use. Oxyfluorfen + oxadiazon was safe on all tested plant species and can be applied 2 weeks before, at, or 2 weeks after sticking stem cuttings. The results indicate certain preemergence herbicides can be applied during stem cutting propagation when used in accordance with product label restrictions.

Organic crop production systems are widely valued for their impacts on environmental and health benefits. However, they often face practical production challenges related to soil fertility, nutrient availability, weed management and overall crop productivity. Cover crops have emerged as an effective, sustainable and adaptable practical solution to address these challenges. This review synthesizes current evidence on cover crops as multifunctional ecological regulators in organic crop production systems with a focus on their role in improving the soil ecological functions by supporting soil physical structure, chemical fertility, and biological activity. To avoid conceptual ambiguity, we distinguish cover crops retained as surface mulch from green manures incorporated into soil, living mulches grown with cash crops, and cover crop-based reduced- or no-tillage systems. It highlights various functional groups of cover crops such as legumes, cereals/grasses, brassicas, and selected broadleaf species, and their mixtures deliver complementary benefits such as nitrogen fixation, nutrient retention, improved soil aggregation, nourishing microbial biodiversity, weed suppression, and accumulation of organic matter. These functions supports the key ecosystem services, ultimately contributing to elevated crop performance across wide range of crops including vegetables, fruits, herbs and ornamentals. However, the effectiveness of cover crop adoption relies on proper management practices, including species selection, termination timing, and alignment of nutrient release to meet crop demand. This review also acknowledges the potential trade-offs, such as nutrient immobilization and resource competition which requires careful consideration in practice. Future research should prioritize understanding the long-term impacts of cover crops, multi-site studies optimizing species mixtures across functional groups, and adaption of cover crops in organic crop production systems to changing climatic conditions. Integrating cover crops with no-till, conservation tillage and precision management offers promising opportunities to enhance overall effectiveness in organic systems. Overall, this review paper highlights the central role of cover crops in strengthening organic production systems by improving soil health, enhancing resilience, and supporting long-term sustainability of organic crop production systems.

This study evaluated the impact of four organic soilless substrate combinations on the plant parameters of organic kale ( Brassica oleracea var. acephala ‘Lacinato’) and organic Swiss chard ( Beta vulgaris var. cicla ‘Ruby/Rhubarb Red Chard’) in a vertical farming system. Trials were conducted during spring and fall 2023 in a high tunnel at Tennessee State University's certified organic farm. The substrate combinations included pine bark:compost (PBC), pine bark:coffee chaff (PBCC), pine bark:peat moss (PBPM), and peat moss:perlite (PMPL). Their physical properties (air space, water holding capacity, total porosity, bulk density, and volumetric water content) and influence on plant attributes (fresh weight, plant height, number of leaves, chlorophyll, and sugar content) were evaluated. Plants were grown in stackable pots within vertical towers and irrigated via drip lines. PMPL showed highest water holding capacity (77.0% and 74.4%) and porosity (86.6% and 84.0%) in spring and fall. While PBCC demonstrated highest air space (24.7% and 20.3%) and bulk density (0.358 g·cm −3 and 0.329 g·cm −3 ) in spring and fall trials. Although many plant attributes were not significantly different across treatments, fresh weight trends favored kale in PBC (413.74 g) in spring and PMPL (448.42 g) in chard. Trends indicated slightly higher chlorophyll content in PBCC and PBPM. Kale grown in PBCC illustrated highest sugar accumulation (10.08%) in fall. Overall PMPL performed best in yield and moisture retention, while PBCC enhanced sugar content. These findings highlight the importance of substrate choice in optimizing productivity of vertical and urban organic farming systems using sustainable inputs.

Indaziflam was evaluated in Connecticut and Tennessee for weed control and safety of container-grown ornamental plants. Indaziflam was applied at 49, 98, or 196 g ha-1 to container-grown ornamental plants on an outdoor gravel pad and also applied preemergence or early postemergence to weeds in a greenhouse. Ornamental plants were treated twice annually in 2020 and 2021 in Connecticut, and in 2019 and 2020 in Tennessee, with approximately 6 wk between applications. Chinese pyramid juniper, common juniper, eastern hemlock, eastern white pine, and Norway spruce in Connecticut, and 'Andorra Compacta' creeping juniper and 'Black Dragon' Japanese cedar, 'Blue Rug' creeping juniper, and 'Blue Pfitzer' Chinese pyramid juniper in Tennessee were not injured with indaziflam regardless of the rate applied. Preemergence application of indaziflam reduced densities of creeping woodsorrel, hairy bittercress, giant foxtail, and large crabgrass by 72% to 100%, depending on the indaziflam rate applied, by 28 d after treatment (DAT). When applied early postemergence, indaziflam provided 97% to 99% control of creeping woodsorrel (1- to 2-leaf), fringed willowherb (4- to 6-leaf), hairy bittercress (cotyledon to 1-leaf), and mouse-ear chickweed (2- to 4-leaf) by 28 DAT. Compared with a nontreated control, the total fresh shoot biomass reduction was 86% to 100% and 78% to 100% following preemergence or postemergence applications. Indaziflam offers a new site of action with excellent safety and weed control in the tested ornamental plants.

To support the growing global population, sustainable farming methods like vertical farming must complement traditional agriculture. This study evaluated the effects of various nitrogen fertilizer application rates (N_low (1055.3 ppm), N_rec (1640.9 ppm), N_high (2811.3 ppm), and N_0 (469.9 ppm)) on organic kale (Brassica oleracea L. var. acephala ‘Lacinato’) and Swiss chard (Beta vulgaris subsp. Vulgaris ‘Ruby/Rhubarb Red’), grown in a vertical growing system installed in a high tunnel during the spring and fall season of 2023 at the organic farm of Tennessee State University. Growth parameters studied included fresh weight, Brix, chlorophyll, plant height, and leaf count. Most parameters did not exhibit statistically significant differences (alpha = 0.05). However, consistent numerical trends and deviations were observed. Although not statistically significant, kale achieved the highest mean fresh weight in N_rec (688.08 g), and Swiss chard in N_high by spring (649.62 g). Among the few parameters, significant differences were observed for Swiss chard plant height (48.07 cm) and leaf count (47.25), with N_high during fall. Findings suggest that while definitive conclusions were limited, recommended nitrogen rates (N_rec) may enhance crop performance and contribute sustainable yields in resource constrained vertical farming systems. Further controlled studies are warranted to validate trends and refine nutrient strategies in vertical growing system.

Weed control in cutting propagation is limited to manual hand weeding, which is time-consuming and labor-intensive. Preemergence herbicides and mulches may be viable weed control methods for cutting propagation, but crop safety and weed control efficacy must be better understood. Four preemergence herbicides (indaziflam, isoxaben, isoxaben + dithiopyr, and oxyfluorfen + oxadiazon) and two mulches (pine pellets and rice hulls) were assessed in cutting propagation for their impact on rooting and subsequent liner growth (butterfly bush [Buddleja davidii Franch.] and crape myrtle [Lagerstroemia indica L.]) and control of four common weed species. Butterfly bush cuttings had lower rooting percentage and root dry weight with isoxaben and isoxaben + dithiopyr, but no damage was observed for all other treatments during propagation or after transplant. Crape myrtle cutting root development and liner growth were statistically similar for all treatments compared to the non-treated control. Isoxaben, isoxaben + dithiopyr, oxyfluorfen + oxadiazon, and pine pellets provided excellent control (87 to 100%) of all four weed species tested. Overall, several preemergence herbicides and mulches were safe for use in cutting propagation and effective weed control varied by product and weed species.

Early and accurate detection of diseases, and implementation of efficient disease management practices are crucial to reducing the economic impact associated with plant disease outbreaks. Based on survey responses from dogwood nursery growers in Tennessee, USA, scouting was identified as an important disease management practice adopted by a majority of growers for disease management in field-grown, container-grown, and pot-in-pot production systems. Our results show a significant positive correlation between disease severity and scouting frequency for dogwood plants grown in container and pot-in-pot production systems. Our efficiency measure is a self-rated efficacy scale perceived by the nursery growers about their existing disease management system in nursery plants. A significant positive correlation was found between the efficacy of disease management and the number of workers involved in scouting and a negative association between the worker hours spent in scouting and the grower's experience/exposure to other disease detection methods. The majority of nursery growers followed a set spray schedule between May and October, with applications scheduled every other week. In addition, our results showed significant positive correlations between efficacy and spray-related factors, such as disease severity and worker hours spent in spraying; efficacy of disease management and spraying frequency in field-grown dogwoods; and foliar spray costs and efficacy of disease management. We estimated ≈$379/acre per year average costs for dogwood disease management, which the growers find to be one of the major components of the dogwood production budget. Moving to automated systems of disease scouting and management has the potential to reduce the cost of these labor-intensive disease management practices of dogwood production.

The understanding of how solitary and combined use of covercrop species and seeding rates influences soilborne diseases is lacking. Cover crops (crimson clover, triticale and crimson clover + triticale) were seeded in the field plots in September 2019 (Trial 1) and September 2021 (Trial 2) at two seeding rates (low and high) and a no cover cropped fallow served as a control. The soil was collected from all the plots in the following June. Red maple rooted cuttings were planted in nursery containers filled with those soils and plant health was evaluated with and without inoculation with Phytophthora nicotianae, Phytopythium vexans and Rhizoctonia solani. Plant height and fresh weight were measured, and plant roots were assessed for root rot severity (0-100% roots affected) and pathogen recovery. The number of fluorescent Pseudomonads present in soil samples was counted. Root rot severity and pathogen recovery were less with plants grown in cover cropped soil compared to non-cover cropped soil. Root rot severity caused by all three pathogens was least with the plants grown in the crimson clover and mixed cover cropped soil with the mixture being better than crimson clover. Moreover, plants grown in the high rate of cover cropped soil had less root rot severity compared to plants grown in low seeding rate cover cropped soil. Plant fresh weight was greater for plants grown in the high rate of crimson clover cover cropped soil and, in the mixture, compared to the non-cover cropped soil, whereas height was least affected. The Pseudomonad population was greatest in mixed cover cropped as well as in the high rate of cover cropped soil. Our findings suggest that a mixture of cover crop species and high seeding rate provides better service in suppressing root rot diseases likely associated with biological processes and nutrient availability. La comprehension relative a l'influence de l'utilization seule ou combinee des especes de plantes de couverture et des taux de semis sur les maladies terricoles fait defaut. Des plantes de couverture (trefle incarnat, triticale et trefle incarnat+triticale) ont ete semees dans des parcelles de terrain en septembre 2019 (Essai 1) et septembre 2021 (Essai 2) a deux taux de semis (faible et eleve), et une jachere sans plantes de couverture a servi de temoin. Au mois de juin suivant, du sol a ete preleve dans toutes les parcelles. Des boutures racinees d'erable rouge ont ete plantees dans des pots de pepinieres remplis de ce sol, et la sante des plants a ete evaluee avec et sans inoculation de Phytophthora nicotianae, de Phytopythium vexans et de Rhizoctonia solani. La taille et le poids frais des plants ont ete mesures et les racines ont ete evaluees en fonction de la gravite du pourridie (de 0 a 100% des racines infectees) ainsi que du taux de recuperation des agents pathogenes. Le nombre de pseudomonas fluorescents contenus dans les echantillons de sol a ete calcule. La gravite du pourridie et le taux de recuperation des agents pathogenes etaient plus faibles chez les plants qui avaient beneficie d'un sol couvert d'une protection vegetale que chez ceux qui n'en avaient pas beneficie. La gravite du pourridie cause par les trois agents pathogenes etait plus faible chez les plants ayant beneficie d'une couverture de trefle incarnat et du melange de plantes de couverture, le melange etant plus efficace que le trefle seul. De plus, les plants cultives dans un sol ayant beneficie d'un taux de semis eleve affichaient moins de pourridie que les plants cultives dans un sol a faible taux de semis. Le poids frais des plants etait plus important chez les plants cultives dans un sol a taux eleve de trefle incarnat tandis que le melange a produit un resultat comparable a celui du sol sans couverture, par ailleurs, la taille etait moins influencee. La population de pseudomonas etait la plus dense dans les sols ayant beneficie d'une couverture mixte ainsi que dans les sols densement ensemences. Nos resultats suggerent qu'un melange d'especes de plantes de couverture et que des taux de semis eleves sont plus efficaces pour supprimer les pourridies vraisemblablement associes aux processus biologiques et a la disponibilite des nutriments.

Early season monitoring of nutrient stress is important in red maple (Acer rubrum L.) and flowering dogwood (Cornus florida L.) to optimize management practices and ensure healthy crop production in containers. Two different irrigation systems (drip and overhead irrigation) were used in this study. Two rates (low and high) of controlled-release fertilizer were used with no fertilizer as a control treatment. Data were recorded for plant height, stem diameter, substrate pH and electrical conductivity (EC), chlorophyll content, normalized difference vegetation index (NDVI), visual observation of plant quality, and leaf nutrient content. The results of this study showed that the increase in plant height and stem diameter was greater among the fertilized maple tree, whereas no differences were observed in the flowering dogwoods for an increase in plant height. NDVI was greater for drip irrigation for both fertilizer rates in both red maples and flowering dogwoods. A positive correlation of 73% to 83% was observed for red maples and 79% to 83% was observed for flowering dogwoods between handheld NDVI and unmanned aerial vehicle-mounted NDVI sensors. In red maple, a high fertilizer rate resulted in greater substrate pH, whereas in flowering dogwood, no differences were observed. Varied responses were observed among the treatments for nutrient content; however, both rates of fertilizer application were sufficient for both tree species. Drip-irrigated red maples had higher nitrogen and phosphorous content, whereas nitrogen content was higher in both irrigation systems in flowering dogwoods. This study provides useful insights into understanding the effect of nutrient stress on tree growth and the application of sensing technology for the monitoring and early detection of nutrient stress in container-grown nursery crops.

Ornamental plant and weed response to oxyfluorfen + prodiamine herbicide was evaluated in Connecticut and Tennessee, USA, in 2017 and 2018. Preemergence application of oxyfluorfen + prodiamine was made at 0 lb/acre, 2 + 0.75 lb/acre, 4 + 1.5 lb/acre, and 8 + 3 lb/acre to container-grown ornamental plants on an outdoor gravel pad and weeds in greenhouse experiments. Ornamental plants were treated first within a week after transplanting and again 6 weeks after the first treatment. Asiatic jasmine (Trachelospermum asiaticum), candlestick plant (Senna alata), and English ivy (Hedera helix) in Tennessee, USA; and ‘Blue Flag’ iris (Iris sp.), ‘Firecracker’ gladiolus (Gladiolus sp.), and ‘Green Carpet’ Japanese pachysandra (Pachysandra terminalis) in Connecticut, USA, were not injured with oxyfluorfen + prodiamine regardless of rate applied. Lily-of-the-Nile (Agapanthus africanus) in Tennessee, USA, and ‘Bowles’ periwinkle (Vinca minor) in Connecticut, USA, showed minor but commercially acceptable growth reduction with oxyfluorfen + prodiamine up to 4 + 1.5 lb/acre. Shasta daisy (Leucanthemum ×superbum) in Connecticut, USA, was the most sensitive ornamental plant. After the first application, average necrotic injury to Shasta daisy varied from 24% with 2 + 0.75 lb/acre to 31% with 8 + 3 lb/acre of oxyfluorfen + prodiamine. After the second application, necrotic injury was ≤ 5% with all oxyfluorfen + prodiamine rates tested and was commercially acceptable (≤ 20%). Oxyfluorfen + prodiamine reduced densities of creeping woodsorrel (Oxalis corniculata), hairy bittercress (Cardamine hirsuta), giant foxtail (Setaria faberi), and large crabgrass (Digitaria sanguinalis) ≥ 80% by 4 weeks after treatment. The fresh weed biomass 6 weeks after treatment indicated an 88% to 99% reduction compared with the untreated control.

Flatheaded borers (FHB; Chrysobothris spp.), are woodboring-beetles that lay their eggs in the bark and cambium of deciduous trees in North America. Females often target stressed host-plants for oviposition. The reason why is unknown; however, stressed plants often suffer various induced phytochemical changes that may enhance larval infestation success depending on the stressor such as induced upregulation of defenses, reallocation of nutrients, and changes to volatile organic compound (VOC) emissions. To understand attraction of FHB to specific stress-induced changes, we analyzed phytochemical changes associated with stress treatments and attractiveness maple trees to FHB. Trees were stressed by: (1) chemical stress (pelargonic acid herbicide), (2) physical stress (physically removing leaves), and (3) physical stress (removing portions of bark near the root crown). After reflush of defoliated trees, bark tissues where FHB larvae feed were analyzed for nutritional changes (carbon and nitrogen), anti-nutritive changes (polyphenols and tannins) and emissions of foliar VOCs. At the end of the growing season, trees were assessed for FHB larval presence and oviposition attempts. There were more larvae and oviposition attempts on trees stressed by herbicide application. Compared to other treatments, herbicide-stressed trees had greater nitrogen and total polyphenol concentrations. Greater nitrogen may play a role in the fitness of feeding larvae, and the greater polyphenol concentration may stimulate female oviposition in the herbicide stressed trees. Females may be able to locate the herbicide-stressed trees by using volatile cues such as increases in limonene, α-farnesene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and hexenyl acetate.

Flowering dogwoods (Cornus florida L.) are drought-sensitive ornamental trees. Two trials (in 2021 and 2022) were conducted to evaluate the physiological changes induced as a result of drought conditions. In an outdoor setting, trees were organized in a randomized complete block design. Three different irrigation treatments were applied at 125%, 25%, and 10% (control, moderate, and severe drought, respectively) of their daily water usage (evapotranspiration). The two physiological parameters normalized difference vegetation index (NDVI) and leaf moisture potential were collected every week for 1 month. Plant growth data (height and width) were collected at the beginning and the end of the study. Normalized difference vegetation index data collected with a handheld NDVI meter and a Sentera NDVI sensor mounted on an unmanned aerial vehicle (UAV) were correlated for ground truthing. In 2021, control plants had a greater plant width increase and shoot biomass, whereas no significant differences in growth were observed among the treatments in 2022. In both trials, the NDVI was the greatest for control plants compared with the other treatments on days 7, 14, 21, and 27. In both studies, no differences were observed for leaf moisture potential on day 7, but was greatest for controls on days 14, 21, and 27. The correlation between the handheld NDVI and the UAV NDVI was found to be strong and positive, ranging from 0.84 to 0.93 (trial 1: P ≤ 0.0001, P ≤ 0.0001, P = 0.0002, and P ≤ 0.0001; trial 2: P = 0.0002, P ≤ 0.0001, P ≤ 0.0001, and P ≤ 0.0001 for weeks 1–4, respectively). This information will be applicable to understanding the physiology of the crop and the inclusion of emerging technology in crop production and monitoring.