Widespread outbreaks of tomato powdery mildew (Leveillula taurica and Oidium neolycopersici) are problematic in fresh market tomato (Solanum lycopersicum) crops in western Oregon, USA. In western Oregon, fresh market tomatoes are frequently grown in greenhouses or high tunnels where conditions can promote diseases such as powdery mildew. Heightened concerns about worker safety limit the pesticides available for use in enclosed systems. We studied the efficacy of ultraviolet-C (UV-C) light applications under high-tunnel conditions compared with a standard fungicide program. Plants treated with UV-C had zero incidence of powdery mildew on all sample dates in the first trial. In trial 2, disease incidence was lower on UV-C treated plants than both grower standard and nontreated control early in the study while disease severity remained lower in UV-C than nontreated control and similar to grower standard treatment. Additional research is needed to optimize UV-C treatment intervals to minimize negative effects on plant growth and maximize powdery mildew control.
Most lake, canal, and pond management programs in the United States use herbicides labeled for aquatic use because many of these products, which are registered by the US Environmental Protection Agency, are relatively inexpensive and can effectively control undesirable plants without excessive damage to desirable species. Managers of these resources have expressed an interest in alternative methods for aquatic weed control that could reduce the use of traditional synthetic herbicides. We studied the effects of acetic acid and d-limonene on growth of the invasive aquatic species rotala (Rotala rotundifolia) and crested floatingheart (Nymphoides cristata), as well as on the native wetland plants spatterdock (Nuphar advena) and giant bulrush (Schoenoplectus californicus). We applied acetic acid and d-limonene (alone and in combination) once as foliar treatments to healthy plants, then grew out the plants for 8 weeks after treatment to observe damage resulting from treatments. We also evaluated diquat dibromide at three concentrations as “industry-standard” synthetic treatments for comparison. A 0.22% concentration of diquat dibromide eliminated most or all vegetation of rotala, crested floatingheart, and giant bulrush, but was much less damaging to spatterdock. Single-product applications of acetic acid or d-limonene had little effect on any of the four species evaluated. Some combinations of acetic acid and d-limonene provided acceptable control of rotala and selectivity on spatterdock and giant bulrush, but no treatments reduced crested floatingheart growth by more than 40%. Treating rotala with acetic acid and d-limonene instead of diquat dibromide would result in a 25-fold increase in material costs, which would make this option unaffordable for most aquatic system managers.
Integrated pest management (IPM) is an important component of golf course maintenance and includes conventional chemical pesticide use as well as nonchemical cultural management practices. Determining how frequent pest management practices are used on golf courses is critical when developing educational and outreach programs. The objective of this study was to determine the frequency of pest management practices and pesticide mixing and storage facilities on US golf courses. A survey was sent to 14,033 operational US golf facilities with 10% responding. Reliance on all conventional chemical pesticides increased from 2015 to 2021. The reliance on biological control products declined to 14% and reliance on the nonpesticide practice of using plant growth regulators remained equivalent to 2015. The most common pest management practices included monitoring weather patterns and scouting for pests, with 93% of golf facilities reporting the use of both. The use of written IPM and pesticide application plans increased from 44% to 63% of golf facilities between 2015 and 2021, respectively. Generally, mixing and storage facilities remained unchanged from 2015 to 2021. US golf facilities continue to use nonchemical pest management practices, but reliance on chemical pesticides has increased.
Increasing demand on agricultural water resources have caused a greater need for the use of municipal recycled wastewater (MRW) globally. However, in the United States, greenhouse growers have been slow to use it in their greenhouse operations. In this study, we seek to understand the factors that motivate and limit use of MRW among US growers. Using national survey data from 2019 through 2020, we developed a logistic regression model to understand the many factors influencing growers’ willingness to use MRW on food crops. We find that MRW quality is a primary concern and that growers’ willingness to use MRW is shaped by their direct and indirect knowledge of MRW, garnered from their own and others’ experiences using it. Given these findings, improving adoption of MRW requires collective experiential learning opportunities that gather target audiences with educators, policymakers, end users, and local authorities to simultaneously provide hands-on experience tailored to growers’ particular knowledge and concerns with feedback from peers.
Irrigation methods that can minimize water use are needed, and the performance of recently released ‘KSUZ 0802’ hybrid zoysiagrass (Zoysia matrella × Zoysia japonica) has not been evaluated under such management. Therefore, field experiments were conducted in Manhattan, KS, and Dallas, TX, USA, to compare the amount of water applied and ‘KSUZ 0802’ performance and recovery resulting from irrigation using the following: 1) routine irrigation (1.2 inches/week), 2) evapotranspiration (ET)-based irrigation (60% of reference ET), 3) soil moisture sensor (SMS)-based irrigation, and 4) no irrigation. The experiment was conducted under a rainout shelter in Kansas from 15 Jul to 27 Sep 2019 and 8 Jun to 19 Oct 2020, and in Texas the experiment was conducted under open field conditions from 22 Jun to 9 Sep 2020. The SMS-based irrigation method in Kansas reduced water application by 68% and 52%, respectively, compared with routine or ET-based irrigation. In Texas, the corresponding water savings were 29% and 13%, respectively. The water savings discrepancy was mainly due to differences in local weather conditions and irrigation demand. Visual turf quality of turf receiving SMS-based irrigation remained above the minimally acceptable level throughout the study in Kansas, whereas in Texas, turf quality declined below acceptable level after 2 weeks. In Kansas, turf retained acceptable quality for more than 21 days with no irrigation, and after rewatering, nonirrigated turf recovered back to significant green cover (93% in 2019 and 67% in 2020). ‘KSUZ 0802’ demonstrated good drought tolerance and recovery in Kansas.
Biobased sprayable mulch (BSM) films are a potential alternative to herbicides, polyethylene plastic mulch film, and hand weeding for specialty crops. We developed a series of BSM films using locally available biomaterials [including corn (Zea mays) starch, glycerol, keratin hydrolysate, corn gluten meal, corn zein, eggshells, and isolated soy (Glycine max) protein] and tested their effects on weeds and crop yield during a total of seven greenhouse or field trials between 2017 and 2019 in Nebraska, USA. Application rates of BSM films applied in pots (greenhouse), planting holes in plastic film (field), or bed tops (field) ranged from 0.9 to 18.2 L⋅m−2; they were applied before and after the emergence of weeds. Weed control efficacy was variable, and results of greenhouse pots were rarely replicated under field conditions. Increasing the viscosity of the final suspension tested [BSM7; a mix of corn starch (72.8 g⋅L−1), glycerol (184.7 mL⋅L−1), keratin hydrolysate (733.3 mL⋅L−1), corn zein (19.8 g⋅L−1), and isolated soy protein (19.8 g⋅L−1)] reduced weed biomass by more than 96% in field-grown kale (Brassica oleracea var. sabellica) when applied to bare soil bed tops before or after weed emergence, but kale yield in treated plots was not different from the weedy control. The results demonstrated the potential for postemergence applications of BSM films, which increase application timing flexibility for growers. Further research is needed to explore the effects of BSM films on soil properties and crop physiology and yield.
Students enrolled in a landscape plant identification course were assigned a plant project at the beginning of the semester that comprised a written portion and a presentation portion. During the Spring 2014 semester, an electronic slide presentation portion was replaced by a “trade show” display presentation format. The modification was implemented to provide a more meaningful and applicable learning experience because trade shows are important events in the horticulture industry. Using this format, students were required to present or sell their plant genus by constructing an informative display, similar to that used for a tradeshow. Groups of students presented on different days. Students who were not presenting or selling were the “customers,” and they perused the trade show to learn about the various genera. A postactivity assessment survey was administered to gain insight into the student learning experience. The activity was evaluated during five spring semesters. Students responded that they were more comfortable with the trade show style of presentation than with a traditional presentation style, with a Likert scale rating of 1.5 (1–5). When asked to rate their ability to be creative with this activity, students agreed (Likert scale rating of 4.2) that the trade show activity allowed them to be creative. Eighty-nine percent of the students liked the activity. When asked to rate the activity compared with a more traditional speech in front of the class, students gave it a rating of 1.4, which is between excellent and above average. During the five semesters, nearly all students (97%) recommended that the trade show activity should be implemented again in future classes. The trade show format was well-received by students and can assist with the professional skills development of students.
Agricultural bioinoculants containing arbuscular mycorrhizal fungi represent a potential opportunity to reduce the dependence of grapevines (Vitis) on agrochemicals. This field study assessed the ability of four commercial bioinoculants to colonize grapevine roots and their effects on petiole nutrient concentration, berry composition, and root morphology of ‘Pinot noir’ (Vitis vinifera) grafted onto rootstock ‘Couderc 3309’ (Vitis riparia × Vitis rupestris) and ‘Riesling’ (V. vinifera) grafted onto ‘Couderc 3309’ and Selection Oppenheim four (Vitis berlandieri × V. riparia). Three bioinoculants increased root mycorrhizal colonization; however, regardless of the treatment, mycorrhizal fungal structures were enhanced. Grapevine petiole nutrient concentration was improved by bioinoculants. Root diameter, root length density, and specific root length increased with greater mycorrhizal root colonization. Using bioinoculants to reduce chemical fertilizers may be a good strategy to improve grapevine productivity and health in cool climates; however, the impact of mycorrhizal bioinoculants in the vineyard may differ among scion–rootstocks, edaphoclimatic conditions, and vineyard soil microbiomes.
Organic growers of cucurbit (Cucurbitaceae) crops in the midwestern United States have difficulty managing bacterial wilt—a fatal disease with a pathogen (Erwinia tracheiphila) that is transmitted by striped and spotted cucumber beetles (Acalymma vittatum and Diabrotica undecimpunctata howardi, respectively). Registered organic insecticides lack effectiveness, and host plant resistance is rare in commercial cultivars of many cucurbit crops. Row covers are widely used as barriers to minimize pest access, but the spunbonded polypropylene fabric covering traditional low tunnels must be removed at bloom to prevent overheating and facilitate pollination, thereby exposing the crop for the rest of the season. “Mesotunnels”—nylon mesh fabric covering 3.5-ft-high hoops—provide more space than low tunnels and mitigate overheating. In field experiments at Iowa State University (Ames, IA, USA) during 2016–18, two variations of mesotunnels—full-season tunnels [with purchased bumble bees (Bombus impatiens) added for pollination] and part-season tunnels (with covers removed for 2 weeks during bloom to provide pollinator access)—were compared with low tunnels and a noncovered treatment for organic ‘Athena’ muskmelon (Cucumis melo) production. Based on scouting results, full-season mesotunnels required no insecticides and part-season mesotunnels averaged 0.6 spray per season compared with 1.0 and 5.0 sprays per season for the low-tunnel and noncovered treatments, respectively. Incidence of pest and disease damage was zero for the full-season mesotunnels, 5% to 22% for the part-season mesotunnels, and 37% to 70% for both of the other treatments. Marketable yield for the full-season mesotunnel treatment exceeded the noncovered treatment significantly each year, and mean marketable yields were greater numerically than for the other treatments. Both mesotunnel treatments had a marketable yield that averaged more than twice that of the noncovered treatment in each year. Economic analysis (partial budget and cost-efficiency ratio) indicated that mesotunnels were likely to be more profitable in Iowa, USA, than either the low-tunnel or noncovered systems, but also that the year-to-year differential among treatments in profitability could be substantial. Additional experiments are needed to evaluate the efficacy of these integrated pest management practices and their profitability at spatial scales representative of commercial farms.
Firmness is an important fruit quality trait in northern highbush blueberry (Vaccinium corymbosum). Many researchers, growers, and packers rely on machines for measuring firmness right after harvest and during postharvest cold storage of fresh fruit. In this study, we compared two machines that use compression firmness measurements to determine a force-deformation value. The first firmness-testing machine has been in use for the past 30 years by blueberry (Vaccinium) researchers and packers worldwide. The second has been on the market for the past 5 years. We compared fruit firmness and size measurements for several commercial cultivars and breeding accessions of northern highbush blueberry by both machines at harvest and 2 weeks postharvest. In general, we found there were slight differences in fruit firmness and size measurements between the two machines, but these measurements were generally consistent across the machines. Our study suggests that, in general, one machine can predict the measurements taken on the other machine.