35 research outputs found
Turfgrass species composition, resistance mechanisms, and management strategy impacts on brown patch incidence and weed encroachment
No full textTall fescue (Festuca arundinacea Schreb.) has great utility as a low maintenance turfgrass in the northern and transition zone regions of the United States. However, it is difficult to successfully maintain tall fescue of high quality over consecutive summers because of its susceptibility to the fungal pathogen Rhizoctonia solani, which causes the disease brown patch. Not only is brown patch aesthetically unpleasing in a stand of tall fescue but it can also thin out the turf and allow for the encroachment of undesirable weedy species. Cultivar selection, cultural practices, mixing turf species and timing of pesticide applications all can impact the epidemiology of brown patch in tall fescue. Research was conducted in tall fescue to quantify chitinase activity in different cultivars, elucidate the impact of mowing height and nitrogen fertility on brown patch and bermudagrass (Cynodon dactylon L.) encroachment, to evaluate seeding mixtures of tall fescue with hybrid bluegrass (Poa pratensis x Poa arachnifera) on diseases and weeds as well as measuring the impact of the herbicide bispyribac-sodium on brown patch. Chitinase activity was greater in the tall fescue cultivar that was less susceptible to brown patch. In the mowing-fertility studies, cutting tall fescue at 10 cm generally reduced brown patch and bermudagrass encroachment compared to 6 cm. Mixing hybrid bluegrass with tall fescue reduced disease and weed species infestations compared to tall fescue alone. Applying bispyribac-sodium earlier in April resulted in less brown patch and better weed control compared to application in May. Based on this research brown patch severity and subsequent weed species infestations can be reduced by selecting a tall fescue cultivar with a high basal level of chitinase, mowing it at 10 cm and mixing it with a hybrid bluegrass cultivar.Ph. D
Evaluation of \u3cem\u3ePoa annua\u3c/em\u3e L. Resistance to Mitotic Inhibiting Herbicides
No full textFour bioassays were conducted to evaluate an ecotype of Poa annua L. from Chattanooga for resistance to prodiamine, pendimethalin, and dithiopyr herbicides. MSmedia, filter-paper, and soil-based bioassays all evaluated root growth response in mature seed from the Chattanooga ecotype and a sensitive control. The hydroponics bioassay evaluated mature tiller response. All the bioassays were able to diagnose the Chattanooga population as resistant to prodiamine and pendimethalin. The soil-based bioassay was able to detect minimal resistance to dithiopyr. Additionally, the Chattanooga population exhibited variability of resistance to dinitroanalines
An overview of weeding by robots – focus on European solutions
No full textInternational audienceThis presentation addressed an overview of the European context, mowing towards data-intensive farming, driven by the agfood sector. It is an invited presentation in the framework of a meeting coordinated by Matthew Cutulle (Clemson University) for a Specialty Crop Research Initiative (SCRI) planning grant about Robotic Weed Control in Specialty Crops. The meeting was organized as a side event during the Southeast Regional Fruit and Vegetable Conference. The presentation provides an overview of European trends on the topic, with a focus on the French institutional perspective aiming at the support and development of agricultural robotics to face the lack of labour and the willingness to phase out glyphosate. In this context, the RobAgri association was presented. The last part lists some sources of information about agricultural robotics, with a list of European sources of information on agricultural robotics and automation. The presentation ends with a list of robot examples that were compared from the agronomic point of view
International Journal of Agronomy
No full textCool-season grass species are commonly overseeded into bermudagrass turf for winter color. When the overseeded grass persists beyond the spring; however, it becomes a weed. The ability of perennial ryegrass, Italian (annual) ryegrass, intermediate ryegrass, and hybrid bluegrass to persist in bermudagrass one year after seeding was determined. Perennial ryegrass, intermediate ryegrass, and Italian ryegrass produced acceptable ground cover in the spring after fall seeding. Hybrid bluegrass did not establish well, resulting in unacceptable cover. Perennial ryegrass generally persisted the most one year after seeding, either because of summer survival of plants or because of new germination the following fall. Plant counts one year after seeding were greater in the higher seeding rate treatment compared to the lower seeding treatment rate of perennial ryegrass, suggesting new germination had occurred. Plant counts one year after seeding plots with intermediate ryegrass or Italian ryegrass were attributed primarily to latent germination and not summer survival. Applications of foramsulfuron generally did not prevent overseeded species stand one year after seeding, supporting the conclusion of new germination. Although quality is less with intermediate ryegrass compared to perennial ryegrass, it transitions out easier than perennial ryegrass, resulting in fewer surviving plants one year later.Published versio
Persistence of Overseeded Cool-Season Grasses in Bermudagrass Turf
No full textCool-season grass species are commonly overseeded into bermudagrass turf for winter color. When the overseeded grass persists beyond the spring; however, it becomes a weed. The ability of perennial ryegrass, Italian (annual) ryegrass, intermediate ryegrass, and hybrid bluegrass to persist in bermudagrass one year after seeding was determined. Perennial ryegrass, intermediate ryegrass, and Italian ryegrass produced acceptable ground cover in the spring after fall seeding. Hybrid bluegrass did not establish well, resulting in unacceptable cover. Perennial ryegrass generally persisted the most one year after seeding, either because of summer survival of plants or because of new germination the following fall. Plant counts one year after seeding were greater in the higher seeding rate treatment compared to the lower seeding treatment rate of perennial ryegrass, suggesting new germination had occurred. Plant counts one year after seeding plots with intermediate ryegrass or Italian ryegrass were attributed primarily to latent germination and not summer survival. Applications of foramsulfuron generally did not prevent overseeded species stand one year after seeding, supporting the conclusion of new germination. Although quality is less with intermediate ryegrass compared to perennial ryegrass, it transitions out easier than perennial ryegrass, resulting in fewer surviving plants one year later
Determining the utility of an unmanned ground vehicle for weed control in specialty crop systems
No full textSpecialty crop herbicides are not a target for herbicide discovery programs and many of these crops do not have access to relevant herbicides. High‐value fruit and vegetable crops represent high potential liability in the case of herbicide‐induced crop damage and low acres for revenue. Labor shortages and higher manual weeding costs are an issue for both conventional and organic specialty crop growers. Robotic weeders are promising new weed control tools for specialty crops, because they are cheaper to develop and, with fewer environmental and human health risks, are less regulated than herbicides. However, many of the robotic weeders are too expensive for small growers to use. In the future greater investment into robotic weeders for small scale growers will be important. The Clearpath robotics platform Husky may provide a cheap and autonomous way to control weeds in small diversified specialty crop farms. Being able to work autonomously in multiple soil moisture environments is the driving factor behind optimizing the Husky platform for weed control. Research has been conducted to evaluate the impact of soil moisture and mechanical actuator on mobility and weed control. Though weed control was not commercially acceptable in these studies, future optimizations to the Husky robotics platform have the potential to achieve commercial success
Best practices for managing weeds in South Carolina fall broccoli production
No full textThe establishment of a broccoli industry in the South Carolina will meet the demands of consumers in the state who desire local produce. From a physiological perspective the best time to grow broccoli in South Carolina is the fall. However, during this time period weeds are actively competing with broccoli and can negatively impact yield and quality of the broccoli. Using a pre-plant herbicide coupled with a post-transplant cultivation significantly improves broccoli yield
Influence of Hemp Variety and Weed Free Period on Yield in Coastal South Carolina
No full textHemp is becoming more agriculturally significant across in South Carolina. Little research has been conducted exploring the impact of weed competition on hemp grown in South Carolina. A field experiment was conducted in 2019 to assess yields of 6 hemp varieties commonly grown in South Carolina (Cherry Wine, Hurricane, Cherry Blossom, Therapy, T1, and Boax) when kept weed free for various periods of time (0, 1, 2, 4, and 6 weeks)
