Developing Sustainable and New Alternative Non-chemical Weed Control Strategies for Container Nursery Growers

View the project final report

Commodities

• Additional Plants: ornamentals

Practices

• Crop Production: nurseries
• Education and Training: demonstration, extension
• Pest Management: mulches - general, mulches - killed, mulches - living, mulching - vegetative, mulching - plastic

Five trials were conducted at four locations in central Florida in 2017 and 2018 [Dover (2 separate trials), Ruskin, Balm, and Apopka FL) to determine the efficacy of different mulch types on weed control in container nurseries. Mulch treatments included 1) pinebark mini-nuggets alone; 2) pinebark mini-nuggets applied in combination with M-Binder mulch tackifier (Granite Seed Co., North Lehi, Utah) 3) hardwood-mulch (derived from the invasive Melaleuca tree species) alone; 4) hardwood mulch applied in combination with tackifier; 5) recycled newspaper slurry alone; 6) recycled newspaper slurry used in combination with pinebark nuggets; 7) sawdust applied alone; and 8) sawdust applied in combination with the tackifier. Treatment (9) involved seeding pots with annual ryegrass seeds (Lolium multiflorum) at a rate of 30 lbs. per acre, allowing seed to become established for 6 weeks, and then applying a contact action herbicide (diquat) before seed development to evaluate residue as a weed control tool. A plastic mulch was also evaluated which was comprised of cutting a white on black plastic sheet (white side up) and securing around the entire base of the plant, covering the media surface. These mulch treatments were compared with two control treatments, the first being a chemical control of one of the most commonly used preemergence herbicides [OH2 Ornamental Herbicide (oxyfluorfen + pendimethalin), Everiss, Inc., Dublin, OH] applied at the standard recommended label rate. A non-treated control (no herbicide or mulch) was also used for comparison at all locations with the exception of Ruskin for comparison. Growth of Podocarpus macrocarpus (podocarpus), Ulmus parvifolia (elm) and Ligustrum japonicum (ligustrum) were also evaluated. All mulch treatments significantly reduced weed growth in comparison with the non-treated control. The sawdust and herbicide treatments were the only treatments that did not significantly reduce handweeding time. Across all trial locations and years, plastic and pine bark treatments resulted in the greatest reduction in weed biomass (79 to 97% reduction) and a 66 to 91% reduction in hand weeding time. No growth differences were observed on any of the evaluated species. Results of this study demonstrate that mulch comprised of plastic or pine bark nuggets could be an effective weed management tool for several long-term nursery crops.

The objective of our trial is to evaluate use of mulch as a long-term (multi-month) weed management strategy and compare performance of mulch materials to a commonly used preemergence herbicide or use of no weed management method (non-treated control). The goal of this project was to determine the efficacy of these different mulch materials as well as develop a guideline for growers in terms of using mulch more effectively for weed control and provide cost estimates for using mulch in comparison with preemergence herbicides, the industry standard.