Weed Control in Residential Landscapes Utilizing Commercially Available Alternative Herbicides

Transcription

1 Title: Weed Control in Residential Landscapes Utilizing Commercially Available Alternative Herbicides Investigators: Darren Haver, Ph.D. Water Resources/Water Quality Advisor University of California Cooperative Extension Orange and Riverside Counties 1045 Arlington Drive Costa Mesa, CA Tel: (714) Fax: (714) Cheryl Wilen, Ph.D. Area IPM Advisor University of California Cooperative Extension 5555 Overland Ave. Bldg 4, Suite 4101 San Diego, CA Tel: (858) Fax: (858) Summary of Project Proposal: Retailers are beginning to dedicate shelf space to pesticides that are considered least toxic alternatives; most of them containing essential oils or other natural plant extracts targeting weeds. However, there is little information on the efficacy of these alternative plant based herbicides compared to traditional chemical weed control products, such as Roundup, for the home gardener. The utilization of green products is increasingly becoming a significant market not only for products used in the home, but also those used in the garden. In addition, these green products are being recommended as water qualityfriendly alternatives to traditional herbicides by environmental advocates and water quality regulatory agencies. This project seeks to compare treatment timing and frequency of re treatment of these leasttoxic weed control methods for landscape plantings as well as in cracks and crevices of a hardscape surfaces. Efficacy will be determined through visual evaluations conducted by volunteers from the UCCE Master Gardener of Orange County Budget Summary for July 1, 2009 to June 30, 2010: $25, hvordan man kan reparere en persienne

2 II. Project Description: Introduction Concerns over the quality of urban streams continues to increase as monitoring consistently reveals the presence of potentially toxic levels of pesticides, most frequently insecticides and herbicides (Sprague and Nowell, 2008; Gilliom et al., 2006; Fuhrer et al., 1999;). Research continues to show that the most widely used herbicide, glyphosate, does not severely impact aquatic environments at the concentrations commonly detected in urban streams (Borggaard and Gimsing, 2008; Kolpin et al., 2006). However, the public s increasing demand for safe green products has resulted in many new environmentally friendly products becoming available for controlling weeds in the garden. Even though information for home gardeners on the efficacy of these new products is limited, their use is still heavily promoted by environmental awareness groups, water quality protection agencies, and municipal stormwater programs in an effort to simply reduce the potential contamination of surface waters. In an effort to provide science based information to home gardeners and improve the level of information disseminated by well meaning groups, this project will compare traditional weed control methods with alternative less toxic methods. The majority of these green weed control products are botanically based oils (ex. d Limonene) or acids (ex. pelargonic acid or vinegar) that control weeds by destroying the leaf cuticle or causing cell leakage rapidly leading to death. Unfortunately, long term control is often lacking as weeds with extensive root systems or underground storage reserves are able to recover as the materials are not translocated as with some traditional chemical herbicides such as glyphosate or 2,4 D. Yet even with limited control of weeds, these products may provide sufficient weed control in home garden situations, thereby reducing the possible contamination of surface waters with less environmentally friendly herbicides. This project will investigate if these new products satisfactorily control weeds in hardscape cracks and crevices as well as in new groundcover plantings. Plan of Work Weed control in patio and walkway cracks The experimental configuration will be a randomized complete block design with 4 replications and 8 treatments (Table 1) for a total of 32 plots. Plot size will be 2 x 2 consisting of pavers or bricks set in sand base with unpaved areas between the plots. The site will be irrigated using turf sprinklers. The experiment will be located at South Coast Research and Extension Center. Treatments were selected based on questions posed to the PIs by Master Gardeners at their training meetings. Treatments will be applied directly to the emerged weeds. Ready to use (RTU) formulations of treatments 4 8 will be used if available. Timing will be based on when 67% of the evaluators report they would treat (see evaluation section below).

3 Weeds commonly found in cracks include spotted or prostate spurge, creeping woodsorrel, and annual grasses such as annual bluegrass. We will obtain seeds of these species and overseed at the appropriate seasonal time. In cases where seeds are not available or do not emerge in the control plots, we will substitute with other problematic species such as hairy fleabane or crabgrass. Table 1. Treatments to be used for evaluation of weed control in patio and walkway cracks. 1. Control untreated 2. Hot water boiling water 3. Vinegar undiluted household white vinegar 4. D Limonene e.g. Nature s Avenger or WorryFree (both are 17% A.I.) 5. Eugenol (clove oil) e.g. Bioganic, Matran, Weed Attak, Burn Out 6. Ammoniate soaps of fatty acids/pelargonic acid e.g. Monterey Herbicidal Soap, Scythe 7. Glyphosate Roundup RTU 8. Diquat Reward* *Not typically available for non professionals but is the best comparison to the treatments. Evaluation: Master Gardeners will evaluate the study weekly and rate each plot as control the weeds (1) or wait (0). After each group evaluation, the results will be summarized. When 2/3 of the evaluators rate a treatment as 1 the treatment will be applied. Data collected will include number of times a treatment is applied, weeds controlled 2 days after application. Total cost over one year will also be calculated. Weed control in groundcover plantings The experimental configuration will be a randomized complete block design with 4 replications, 7 weed control treatments (Table 2) and three plant species. Each plot will be planted with 3 commonly used landscape groundcovers: myoporum, blue fescue, and manzanita, i.e. each plot will have 3 species for a total of 28 plots. Plot size will be 3 x 3 with at least 1 border between the plots. The site will be irrigated using shrub sprinklers. The experiment will be located at South Coast Research and Extension Center. Treatments were selected based on questions posed to the PIs by Master Gardeners at their training meetings. Treatments will be applied directly to the emerged weeds. Ready to use (RTU) formulations of treatments 4 8 will be used if available. Timing will be based on when 67% of the evaluator report they would treat (see evaluation section below).

4 Weeds commonly found in groundcover beds include spotted or prostate spurge, creeping woodsorrel, and annual grasses such as annual bluegrass. We will obtain seeds of these species and overseed at the appropriate seasonal time. In cases where seeds are not available or do not emerge in the control plots, we will substitute with other problematic species such as common purslane, hairy fleabane or crabgrass. Table 2. Treatments to be used for evaluation of weed control in groundcovers. 1. Control untreated 2. Hand weed 3. Mulch medium size bark mulch, 3 deep followed by handweeding if indicated by evaluators 4. Corn gluten meal 2 lb/100 ft 2 5. Mustard seed meal 9.3 lb/100 ft 2 6. Glyphosate spot spray 7. Preen Weed Preventer a.i. Trifluralin Evaluation: Master Gardeners will evaluate the study weekly and rate each plot as acceptable (0), tolerable (1), or unacceptable (2). After each group evaluation, the results will be summarized. When 2/3 of the evaluators rate a treatment as 2 the treatment will be hand weeded (except treatments 1 and 6). If treatment 6 is rated as 2, the herbicide will be reapplied. Data collected will include number of times a treatment is applied or hand weeded and groundcover vigor (scale of 1 10 compared to treatment 1 with 10 being most vigorous) and groundcover injury (scale of 1 10 compared to treatment 1 with 10 being dead). Total labor time to weed over a one year period will also be calculated. Expected Outcomes The results of this project will provide home gardeners with specific information on the efficacy of green weed control products compared to traditional herbicides. Because of the push to change the behavior of home gardeners overall use of pesticides, the results will be welcomed by and widely disseminated by local and regional water quality agencies and municipalities. The involvement of UC Master Gardeners in the actual evaluation of both the landscape and hardscape plots will also ensure more widespread dissemination of the results to the general gardening public. Results will be disseminated in newsletter articles provided to HOA property management companies, municipalities, the Better Gardening Practices to Protect Water Quality web site created in a previous outreach project, and in an applied peer reviewed journal such as the Journal of Environmental Horticulture or Journal of Extension (for the Master Gardener aspect).

5 Literature Cited Gilliom RJ, Barbash JE, Crawford CG, Hamilton PA, Martin JD, Nakagaki N, Nowell LH, Scott JC, Stackelberg PE, Thelin GP, Wolock DM The quality of our nation s water Pesticides in nation s streams and ground water, Circular U.S. Geological Survey, Reston, VA. Fuhrer GJ, Gilliom RJ, Hamilton PA, Morace JL, Nowell LH, Rinella JF, Stoner JD, Wentz DA The quality of our nation s waters Nutrients and pesticides. Circular U.S. Geological Survey, Reston, VA. Sprague LA and Nowell LH Comparison of pesticide concentrations in streams at low flow in six metropolitan areas of the United States. Environ. Toxicol. Chem. 27: Borggaard OK and Gimsing AL Fate of glyphosate in soil and the possibility of leaching to ground and surface waters: a review. Pest Manag Sci. 64: Kolpin DW, Thurman EM, Lee EA, Meyer MT, Furlong ET, Glassmeyer ST Urban contributions of glyphosate and its degradate AMPA to streams in the United States.

6 III. Detailed Budget (July 1, 2009 to June 30, 2010) Budget Item Salaries and Benefits (30% time Program Rep I to coordinate data collection with Master Gardeners, assist in dissemination of results to target audience, update web site, and review outreach materials) Amount $11, $ Subtotal (Salaries and Benefits) $17, Supplies and Expenses 1. Pavers/Bricks/Sand/2 x 4 edging for hardscape plots 2. Plant materials (groundcover) for landscape plots 3. Research center labor for project assistance (irrigation, plot grading, etc.) 75 $ Irrigation parts and sprinklers 5. Herbicides (traditional and green alternative) 6. Mulch (includes delivery charge) 7. Weed seed 8. Printing costs (evaluation sheets, brochure or quick tip cards) $ $ $ $ $ $ $ $ Subtotal (Supplies and Expenses) $ Total Budget Request $24, IV. Other Available Funds No pending applications for funds. Outreach materials created in a previous project, specifically the Better Gardening Practices to Improve Water Quality web site for home gardeners, will be populated with the results of this research. V. Curriculum vitae of principal investigators

7 DARREN L. HAVER University of California Cooperative Extension 1045 Arlington Drive Costa Mesa, CA Office: (949) Fax: (949) EDUCATION Ph.D. in Botany & Plant Sciences, University of California, Riverside B.S. in Ornamental Horticulture, California State Polytechnic University, Pomona. WORK EXPERIENCE 2007-present Water Resources/Water Quality Advisor Orange County (70%) and Riverside County (30%) Watershed Management Associate Advisor Orange County (80%) and San Diego County (20%) Water Quality Program Representative III University of California Cooperative Extension Orange Relevant Publications Wilen, C., D. Haver, P. M. Geisel, M. L. Flint, and C. L. Unruh Hiring a pest control company. University of California Agriculture and Natural Resources, Publication Wilen, C., D. Haver, M. L. Flint, P. M. Geisel, and C. L. Unruh Pesticides: safe and effective use in the home and landscape. University of California Agriculture and Natural Resources, Publication Haver, D. L Lawn Care Card Series for Maintenance Gardeners: Protecting Water Quality Through Proper Lawn Care. English and Spanish versions. Haver, D.L., L. Ball, Z. Finch Brochure: Responsible Pest Control Brochure Oki, L., R. Mazalewski, T. Majcherek, S. Bondarenko, D. Haver and J. Gan Detection of pesticides in runoff from residential sources. In: Annual Conference of the American Society for Horticultural Science -Hortscience 42 (4, Suppl. S), July 16-19, 2007, Scottsdale, AZ. Haver, D.L. and T. Majcherek Better Gardening Practices to Improve Water Quality. Master Gardener Advanced Water Quality Training Materials (Water Quality Overview, Nutrients and Pesticides, Irrigation Management, Low Impact Design, Least Toxic Pesticide Alternatives, Fertilizer Management, and Outreach Materials). Haver, D.L. and T. Majcherek Web Site: Orange County Master Gardener Water Quality Outreach ( Last updated December 5, 2008.

8 Cheryl Wilen University of California Cooperative Extension Statewide IPM Program 5555 Overland Ave. Bldg. 4 Suite 4101, San Diego, CA (fax) cawilen@ucdavis.edu Education January, 1989 to March, 1994 Ph.D. in Botany at the University of California - Riverside with emphasis on weed physiology and ecology. Dissertation title: Ecophysiological Mechanisms of Pennisetum clandestinum Invasions in California. June, 1985 to June, 1988 Attended St. Louis Community College at Meremac to improve skills in data processing and computer programming. January, 1981 to May, 1983 Master of Science in Horticulture at the University of Arizona with emphasis on vegetable production and plant protection. Thesis title: Differential Sensitivities of Transplanted Tomato Cultivars to 2,6-Dinitroaniline Herbicides. August, 1977 to December, 1980 Bachelor of Science in Horticulture at the University of Maryland with emphasis on fruit and vegetable production. Employment History September, 1995 to present Area Integrated Pest Management Advisor for Orange, Los Angeles, and San Diego Counties. Conduct applied research with growers and pest control advisors in the turf, ornamental, and nursery industries to help develop successful IPM programs. Extend information through seminars, meetings and publications. Current projects include development and implementation of IPM educational programs for non-commercial pesticide users in San Diego, development of snail control monitoring programs, and rabbit and weed management in nurseries and landscapes. Statewide IPM Program, University of California Cooperative Extension. February, 1994 to September, 1995 Post-doctoral Research Fellow in the Department of Botany and Plant Sciences. Conduct studies on yellow nutsedge (Cyperus esculentus) in the field, greenhouse, and laboratory to establish temperature thresholds for emergence and growth. Develop and test degree-day models to predict emergence and plant development. University of California, Riverside, California. January, 1989 to February, 1994 Graduate Research Assistant in the Department of Botany and Plant Sciences. Conducted and assisted in experiments relating to weed ecology and physiology. Projects included studies on competitive interactions between plants, measurements of growth rates and rates of photosynthesis as an indicator of potential spread of weeds, and electrophoretic examination of plant proteins. University of California, Riverside, California. July, 1983 to December, 1988 Research Biologist heading the secondary level of screening experimental chemicals as preemergent herbicides and herbicide safeners. Evaluated chemicals' activities on whole plants and directing synthesis of compounds as indicated by trend analysis studies. Duties included supervision and coordination of technicians and conducting and interpreting quantitative structure activity studies. Maintained database of compounds' biological activities. Other duties included the interpretation of data for patent attorneys and acting as a liaison between software support personnel and researchers. Monsanto Agricultural Company, St. Louis, Missouri. Additional information Licenses: Pest Control Advisor (PCA) in 3 categories and Pesticide Applicator (QAL) in 2 categories Professional Membership: Weed Science Society of America, Western Society of Weed Science, California Weed Science Society, California Association of Pest Control Advisors Leadership: Co-chair of Turf and Ornamental Section of the California Weed Science Society, Chair of the Teaching and Technology Transfer Section of the Western Society of Weed Science ( ), Chair of the Basic Sciences Section of the Western Society of Weed Science ( ) Awards: Orange County Chapter of California Association of Nurseries and Garden Centers 2002 Research Award. California Weed Science Society 2007 Award of Excellence Selected Recent Publications Bell, C. E., J. M. DiTomaso, and C. A. Wilen Pest Notes: Invasive Plants. UC ANR Publication pp. Newman, J., K. Robb, C. Wilen. In press. Using Integrated Pest Management (IPM) to prevent pesticide runoff. In: A Manual for Greenhouses and Nurseries. Ed. J. Newman and K. Gilbert. ANR Publication. Stapleton, J. J., C. A. Wilen and R. H. Molinar Pest Notes: Soil solarization for gardens & landscapes. UC ANR Publication Varela, L.G., M.W. Johnson, L. Strand, C.A. Wilen, and C. Pickel Light brown apple moth s arrival in California worries commodity groups. California Agriculture April June. Pp Wilen, C. and J. M. Henry Turf gaps: The role of turf management on weeds. CAPCA Adviser 11(5): Wilen, C.A. and C. L. Elmore (revised). Pest Notes: Weed Management in Landscapes. UC ANR Publication 7441.