BIOLOGY, INTERACTION, AND MANAGMENT OF NEMATODES AND WEEDS OF FLORIDA VEGETABLE CROPS

• Sponsoring Institution: State Agricultural Experiment Station
• Project Status: COMPLETE
• Funding Source: STATE
• Reporting Frequency: Annual
• Accession No.: 0208523
• Project Start Date: Aug 1, 2006
• Project End Date: Jul 31, 2011
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611

Performing Department
Citrus Research and Education Center

Non Technical Summary
Environmental problems with the soil fumigant methyl bromide have led to the need to find alternative methods for managing soilborne nematodes, weeds, and disease problems in Florida fruit and vegetable production systems. The project examines and seeks to improve the performance and consistency of chemical and nonchemical alternatives to methyl bromide. A systems approach will be utilized to ensure the consideration of various edaphic, biological, geographical, and ecological factors affecting crop response and pesticidal efficacy of individual and combined pest management tactics.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	1499	1120	50%
213	1499	1140	50%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants; 213 - Weeds Affecting Plants;

Subject Of Investigation
1499 - Vegetables, general/other;

Field Of Science
1120 - Nematology; 1140 - Weed science;

Keywords

alternative fumigants

chemical control

crop production

efficacy

integrated pest management

interaction

soil borne diseases

methyl bromide

nematodes

nutsedge

root knot nematode

soil characteristics

soil fumigation

strawberry

tomato

pepper

weeds

Goals / Objectives
OVERALL OBJECTIVES The overall objectives of this project is to identify, evaluate, and integrate various chemical and nonchemical alternatives to methyl bromide for nematode, weed, and soilborne disease management in south Florida vegetable crops. Objective 2 is to evaluate and validate, in field demonstration and small plot trials, the feasibility of using high barrier, virtually impermeable (VIF) mulch films to reduce emissions and soil fumigant field application rates and to compare crop yield and pest control efficacy. Objective 3 is to quantify the importance and interaction of weeds as reservoir hosts for nematodes and other disease causing agents. Objective 4 is to educate growers, farm workers, and other agriculturalists about current alternatives to methyl bromide research and integrated pest management.

Project Methods
A principal focus of these studies involves the evaluation of VIF mulches coupled with reduced in-row applications of methyl bromide and other soil fumigants in small plot and large scale field demonstration trials. Virtually impermeable plastic mulch films will be field tested in small plot trials and also made available to growers in appropriate widths and lengths for commercial scale field testing. Small plot and large scale grower field demonstration sites will include west central (Ruskin-Palmetto-Plant City), southwest (Naples), or south central Florida locations (Immokalee). Each of the trials will compare at least one alternative chemical and mulch treatment with that of methyl bromide for weed, disease, and nematode control and for tomato, pepper, and or strawberry yield response. For each grower demonstration trial, the treated area for each reduced rate fumigant treatment are likely to be a minimum of 0.5 acres. Plant growth parameters to be evaluated astreatment comparisons include differences in plant size, height, vigor, stand, yield, and nematode and disease incidence and severity ratings. In large scale field validation trials, crop yield information will be acquired only with grower cooperation. As in other project components, all treatments will be replicated four to six times in a randomized complete block design within the field. Statistical analyses and treatment comparisons will be made using SAS ANOVA, Regression, and LSD multiple range tests (P<0.05).

Progress 08/01/06 to 07/31/11

Outputs
Target Audience: Use of grower field demonstration trials was a primary focal area for extension efforts to reinforce methyl bromide alternatives and IPM concepts to methyl bromide dependent growers. Research and extension information, targeting the general public and agricultural stakeholders, was extended via grower and industry training meetings, commodity institutes, field demonstrations, publications, and on-site technical assistance. In general, extension educational programs attempted to characterize physical, chemical, biological, and environmental factors influencing pest, crop management efficacy with the methyl bromide alternatives. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? I have conducted extension activities using direct professional contact and assistance, grower workshops, seminars, field tours and demonstrations, mail distribution of printed materials, and via telephone and internet sources. During the period of this Cris project (2006 to 2012), I played a significant role in educating the public and Ag community of changes in methyl bromide regulatory issues, alternatives research programs, and effective programs for nematode management and transition to alternatives. I am currently relied upon as a primary contact and resource person regarding IFAS/USDA/FFVA/FSGA sponsored methyl bromide research projects. During the period, I have provided for In-Service Training for Cooperative Extension Service Agents (CES) (3), within state CES grower meetings (29), commodity institutes and Expo’s (22), and encouraged growers to participate in over 117 IFAS on-farm demonstration trials during 2006-2012. I have collaborated effectively with UF scientists. I have played a significant leadership role, in conjunction with USDA, FSGA, and FFVA in the planning, implementation, and summary of IFAS research on alternatives to methyl bromide. I have worked collaboratively with FSGA and FFVA to summarize methyl bromide alternatives research with regard to critical needs and continued use of methyl bromide for warranted uses under the Critical Use Exemption (CUE) process. In this regard, I have worked with FFVA, the Florida Tomato Exchange, Florida Potato Growers Association, and FSGA to update varied state, federal, and international agencies regarding the Florida phaseout of methyl bromide, performance of alternatives, and of EPA fumigant reregistration and new relabeling of soil fumigants and the new rules, regulations, and applicator responsibilities imposed by EPA. I have also played a very prominent role, in conjunction with fumigant registrants to provide Florida applicator and handler certifications so as to comply with the new EPA rules. How have the results been disseminated to communities of interest? Noling, J. W. (Presenter). "Identifying Causes of Pest Control Inconsistency with Soil Fumigation in Florida Strawberry." at 2006 Annual International Research Conference on Methyl Bromide Alternatives and Emission Reductions, 11/07/2006, Orlando FL. (Paper). Noling, J. W. (Discussant). "Invited" "Methyl Bromide Replacements and Transition Strategies." at 2006 Florida State Horticultural Society Meeting: Concurrent CES In-Sevice Training, 05/01/2006, Tampa, FL. (Lecture). Noling, J. W. (Presenter). "Effects of Soil Physical Characteristics on Sting Nematode Impacts to Florida Strawberry.." at 2007 Annual Meeting of the Society of Nematologists, 07/01/2007, San Diego, CA. (Lecture). Noling, J. W. (Discussant). "Invited" "Practical Information using Alternatives." at 2007 Southeast Strawberry Expo, 11/01/2007, Durham, NC. (Panel). Noling, J. W. (Discussant). "Invited" " Alternative Fumigants: Physical and Chemical Characteristics Affecting Soil Movement and Efficacy." at 2008 Multi-state Methyl Bromide Alternatives CES In-Service Training, 05/6/2008, Tifton, GA. (Lecture). Noling, J. W. (Discussant). "Invited" " Reports on Field Studies - Both Small Plot and Field Trials ." at 2008 Multi-state Methyl Bromide Alternatives CES In-Service Training, 05/6/2008, Tifton, GA. (Lecture). Noling, J.W. “Invited” “Integrated Crop and Nematode Management”. Certified Crop Advisor Seminar, Lake Alfred, FL. April 8, 2008. (Lecture). Noling, J. W. (Presenter). "Invited" " Alternatives to methyl bromide and New Regulations Governing Future Use of Soil Fumigants." at 2008 AgriTech Seminar and Trade Show, 08/25/2007, Plant City, FL. (Lecture). Noling, J. W. (Discussant). "Invited" "Sting Nematode and Alternatives to Soil Fumigation with Methyl Bromide in Florida Strawberry." at Florida Strawberry Growers Association Visiting Brazilian Seminar and Farm Tour, 11/02//2008, Dover, FL. (Lecture). Noling, J.W. (Discussant). "Invited" Florida Fruit and Vegetable sponsored U.S. EPA Methyl Bromide Alternative Fumigant Farm Tour. Presentations on Methyl Bromide and use of alternatives. 03/14-15/2008. Naples, FL. (Lecture). Noling, J.W. “ Presenter” “ Industry Wide Assessments of Methyl Bromide Alternatives in Florida Strawberry”. 2009 Annual International Research Conference On Methyl Bromide Alternatives And Emissions Reductions. San Diego, California. November 9-13, 2009. (paper). Noling, J.W. “ Presenter” “Transitioning to Methyl Bromide Alternatives: A Current U.S. Assessment”. 2009 Annual International Research Conference On Methyl Bromide Alternatives And Emissions Reductions. San Diego, California. November 9-13, 2009(paper). Noling, J.W. (Presenter) “Current status of chemical alternative technologies for managing soil borne diseases”. 2009 Annual Meeting of the American Society of Phytopathology. Symposia: Methyl Bromide Alternatives Research: Plant Pathology Outcomes. Portland Oregon. August 1-5, 2009. (Paper) Noling, J. W. (Discussant). "Invited" " Transitioning to Methyl Bromide Alternatives ". at Florida Strawberry Growers Association / IFAS sponsored 2009 Strawberry AgriTech Seminar. August 18-19, 2009. Plant City, FL. (Lecture). Noling, J. W. (Discussant). "Invited" " Alternative Fumigants: Physical and Chemical Characteristics Affecting Soil Movement, Concentration, Duration, and Control." at Dade County Cooperative Extension Service Methyl Bromide Alternatives Seminar, May 5, 2009. Homestead, FL. (Lecture). Noling, J. W. (Discussant). "Invited" " Soil Fumigation Update for Strawberry and Vegetable Growers: Timelines for Change". at Bradford County Cooperative Extension Service Methyl Bromide Alternatives Seminar, July 27, 2009. Starke, FL. (Lecture). Noling, J.W. “Presenter” Causes of inconsistency and needs for an integrated approach to the management of plant parasitic nematodes. Symposium II. Organization of Nematologists of Tropical America. Quito, Ecuador. October 3-8, 2010. (Abstract). Noling, J.W. “Presenter” Alternatives to methyl bromide and Sting Nematode management. Florida International Strawberry Conference. Balm, Florida. January 25-27, 2010. (Abstract, Presentation). Noling, J.W. “ Presenter” VIF mulches, optimized irrigation and tillage practices for fumigant use in Florida strawberry. 2010 Annual International Research Conference On Methyl Bromide Alternatives And Emissions Reductions. Orlando, Florida. November 2-5, 2010. (paper). Noling, J.W. “ Presenter” USDA CSREES: Methyl bromide transitions in Florida strawberry 2008-10. 2010 Annual International Research Conference On Methyl Bromide Alternatives And Emissions Reductions. Orlando, Florida. November 2-5, 2010. (paper). Noling, J.W. “Presenter” Assessing field distribution, crop impact and Sting Nematode management in Florida strawberry. 2010 Annual International Research Conference On Methyl Bromide Alternatives And Emissions Reductions. Orlando, Florida. November 2-5, 2010. (paper). Noling, J.W. “Presenter” “Characterizing Fumigant alternatives, Crop Impacts and Field Distribution of Sting Nematode in Florida Strawberry”. 2010 Annual Meeting of the Society of Nematologists. Boise, Idaho. July 11-14, 2010. (Abstract) Noling, J. W. (Discussant). "Invited" "Characterizing Fumigant alternatives, Crop Impacts and Field Distribution of Sting Nematode in Florida Strawberry". at Florida Strawberry Growers Association / IFAS sponsored 2010 Strawberry AgriTech Seminar. August 17-18, 2010. Plant City, FL. (Lecture). Noling, J. W. (Discussant). "Invited" "Methyl bromide transition and the catalysts for change". at 26th annual Florida Seed Association / IFAS sponsored Florida Seedsmen Seminar. February 9-10, 2010. Gainesville, FL. (Lecture). Noling, J. W. (Discussant). "Invited" " Transitioning to Methyl Bromide Alternatives: Viable Options and Considerations ". at Florida CCA/CEU Agronomic Seminar. Florida Crop Consultant Association. April 28, 2010. Sebring, FL. (Lecture). Noling, J.W. “ Presenter” “Alternatives to methyl bromide for soil borne pest and disease control in Florida strawberry”. For the Ecklund Marketing Group- 2010 International Strawberry Grower Seminar and Field Tour. GCREC, Balm, FL. January 18, 2010. Dover, FL. (lecture). Noling, J.W. “ Presenter” “Sting nematode of Florida Strawberry”. For the National Strawberry Growers Association -Canadian strawberry Growers Tour, Florida Strawberry Growers Association Research Farm. January 27, 2010. Dover, FL. (lecture). Noling, J. W. (Discussant). "Invited" " Soil fumigation and weed management”. at UF/IFAS Gulf Coast Research and Education Center- GCREC Strawberry Field Day. February 17, 2010. Balm, FL (Lecture). Noling, J.W. (Discussant). "Invited" Florida Fruit and Vegetable sponsored U.S. EPA Methyl Bromide Alternative Fumigant Farm Tour. Presentations on Methyl Bromide and use of alternatives. April 19, 2010. Ellenton, FL. (Lecture). Noling, J. W. (Discussant). "Invited" "Sting Nematode and Methyl Bromide Alternatives in a Newly Regulated Environment". at UF IFAS sponsored Florida Strawberry Expo in conjunction with North American Strawberry Growers Association Conference and North American Strawberry Symposium. February 11, 2011. UF IFAS Gulf Coast REC, Balm, FL. (Lecture). Noling, J.W. “Presenter” “Alternatives to Methyl Bromide Soil Fumigation for Nematode Control in Florida Strawberry”. 2011 Annual Meeting of the Society of Nematologists. Portland, Oregon. July 16-21. (Abstract) Noling, J. W. (Discussant). "Invited" " Achieving Consistency with Alternatives". at UF/IFAS Florida Tomato Institute. September 8, 2011. Naples, FL. (lecture and paper). What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? During 2006: the combined results of the alternative chemical studies continued to show the combination of 1,3 -D (Telone II) and chloropicrin as the most promising, currently registered, alternative fumigant combination to that of methyl bromide for Florida fruit and vegetable production. In general, these studies indicate that tomato yields were satisfactory with in row applications of Telone C-35. In general tomato yields were near equivalent to that of methyl bromide. The results of recent studies further suggests that when soilborne disease pressure is low, broadcast application of Telone C-35 can be as effective as in bed application; however, when disease pressure is greater, broadcast application of Telone C-35 benefits from the addition of chloropicrin to the finished bed. During 2007, the combined results of the alternative chemical studies continued to show the combination of 1,3 -D (Telone II) and chloropicrin as the most promising, currently registered, alternative fumigant combination to that of methyl bromide for Florida fruit and vegetable production. Field evaluations of Dimethyl Disulfide (DMDS) was also demonstrated to provide strawberry and yield and pest control efficacies equal to or better than that of methyl bromide. In general, these studies indicate that strawberry yields were satisfactory with in row applications of Telone C-35. In general strawberry yields were near equivalent to that of methyl bromide. The results of recent studies further suggests that when soilborne disease pressure is low, broadcast application of Telone C-35 can be as effective as in bed application; however, when disease pressure is greater, broadcast application of Telone C-35 benefits from the addition of chloropicrin to the finished bed. During 2008, the combined results of all alternative chemical studies continued to show the combination of 1,3 -D (Telone II) and chloropicrin as the most promising, currently registered, alternative fumigant combination to that of methyl bromide for Florida fruit and vegetable production. Field evaluations of Dimethyl Disulfide (DMDS) was also demonstrated to provide strawberry and yield and pest control efficacies equal to or better than that of methyl bromide. Methyl iodide and chloropicrin (Midas 50/50; 175 lb/A) was also demonstrated to provide effective pest control and yield response equivalent to that of methyl bromide. In general, these studies indicate that strawberry yields were satisfactory with in row applications of Telone C-35. In general strawberry yields were near equivalent to that of methyl bromide. The results of recent studies further suggests that when soilborne disease pressure is low, prebed application of Telone C-35 can be as effective as in bed drip applications of Telone InLine. Methyl iodide and chloropicrin (Midas 50/50 EC; 175 lb/A) drip fumigation treatments proved ineffective for strawberry yield and pest control. During 2009, field research studies were initiated at UF/GCREC to evaluate various chemical management tactics, chemical application technologies (drip vs chisel), double cropping practices, and treatment regimes to serve as alternatives to soil fumigant uses of methyl bromide. These results show the combination of 1,3 -D (Telone II) and chloropicrin and of Dimethyl Disulfide and Chloroicrin (DMDS+PIC)as promising alternative fumigant combination to that of methyl bromide for nematode management in Florida fruit and vegetable production. During 2010, Research results showed that the 3-way combination of a separately applied herbicide with 1,3 -D (Telone II) and chloropicrin and or of Dimethyl Disulfide and Chloroicrin (DMDS+PIC)as promising alternative fumigant combination to that of methyl bromide for nematode management in Florida fruit and vegetable production. Field surveys are also indicating the differential host status of a diversity of weeds growing within UF/GCREC lands to the southern root-knot nematode, Meloidogyne incognita. All fumigation treatments provided acceptable crop yields in tomato while only methyl bromide, the 3-Way and Midas provided acceptable yields of bell pepper. However, the 3-Way treatment provided the most consistent high yields and weed control. Paladin Pic produced high yields in tomato but also had higher weed counts. These weed counts were greatly reduced with the addition of a herbicide and it would be expected that this product will be required to have a herbicide program as part of its control strategy. In tomato all fumigant systems showed an improvement in weed control with the addition of a herbicide. On Paladin Pic was observed to benefit with the addition of a herbicide for grass control. After year 2 of this trial, all fumigant systems showed promise as a methyl bromide alternative for tomato, but it appears as though a herbicide program may be required for all fumigant systems to improve sustainability, especially that of the 2-Way and Paladin Pic programs. Bell Pepper will require a postemergent grass herbicide for the 2-Way and Paladin Pic to provide good control. During 2011, results again show that the 3-way combination of a separately applied herbicide with 1,3 -D (Telone II) and chloropicrin and or of Dimethyl Disulfide and Chloroicrin (DMDS+PIC)as promising alternative fumigant combination to that of methyl bromide for nematode management in Florida fruit and vegetable production. Very significant differences were apparent in tomato and double crop squash yield, and in weed and nematode population densities among the fall and spring of 2011. Once again, I believe the 3-Way treatment provided the most consistent high yields and weed control. Paladin Pic also produced high yields in tomato but also had higher weed counts, particularly grasses. These weed counts were greatly reduced with the addition of a herbicide and it would be expected that this product will be required to have a herbicide program as part of its control strategy. In tomato all fumigant systems showed an improvement in weed control with the addition of a herbicide. On Paladin Pic was observed to benefit with the addition of a herbicide for grass control. After year 3 of this trial, all fumigant systems showed promise as a methyl bromide alternative for tomato, but it appears as though a herbicide program may be required for all fumigant systems to improve sustainability, especially that of the 2-Way and Paladin Pic programs. Bell Pepper will require a postemergent grass herbicide for the 2-Way and Paladin Pic to provide good control.

Publications

• Type: Conference Papers and Presentations Status: Accepted Year Published: 2006 Citation: Noling, J. W. 2006. "Identifying Causes of Pest Conrol Inconsistency with soil fumigation in Florida Strawberry." 2006 Proceedings Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions. November 6-9, 2006. Orlando, FL. 2006:471-475
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2007 Citation: Noling, J. W. 2007. "Grower Field Demonstration Trialing of Methyl Bromide Alternatives in Florida Strawberry.." 2007 Proceedings Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions. October 28-November 1, 2007. San Diego, CA. 2007:521-528
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2008 Citation: Noling, J.W., Gilreath, J.P., and Kreger. R. 2008. Measuring Fumigant Concentrations and Persistence in Soil with PID - VOC Detectors. 2008 Proceedings Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions. November 10-14, 2008. Orlando, FL 2008: 241-245.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2008 Citation: Noling, J.W., 2008. Large Scale Demonstration Trialing of Methyl Bromide Alternatives in Florida Strawberry. 2008 Proceedings Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions. November 10-14, 2008. Orlando, FL 2008:102-105
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2009 Citation: Noling, J.W. 2009. Transitioning to Methyl Bromide Alternatives: A Current U.S. Assessment. 2009 Proceedings Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions. November 9-13, 2009. San Diego, CA. 2009:21-25.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2009 Citation: Noling, J.W. 2009. Industry Wide Assessments of Methyl Bromide Alternatives in Florida Strawberry. 2009 Proceedings Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions. San Diego, CA. November 9-13, 2009. 2009: 311-315.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2009 Citation: Noling, J.W. 2009. USDA ARS Areawide Project: Large Scale Demonstration Trialing of Methyl Bromide Alternatives in Florida Strawberry. 2009 Proceedings Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions. November 9-13, 2009 San Diego, CA. 2009:391-395.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2010 Citation: Noling, J.W., J. Thomas and M. Cody. 2010. VIF mulches, optimized irrigation and tillage practices for fumigant use in Florida strawberry. Proceedings Annual International Research Conference On Methyl Bromide Alternatives And Emissions Reductions. Orlando, Florida. November 2-5, 2010:161-166.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2010 Citation: Noling, J.W. 2010. USDA ARS Areawide Project: Large scale field demonstrations in Florida strawberry 2009-10. 2010. Proceedings Annual International Research Conference On Methyl Bromide Alternatives And Emissions Reductions. Orlando, Florida. November 2-5, 2010:361-365.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2010 Citation: Noling, J.W. 2010. USDA CSREES: Methyl bromide transitions in Florida strawberry 2008-10. Proceedings Annual International Research Conference On Methyl Bromide Alternatives And Emissions Reductions. Orlando, Florida. November 2-5, 2010:421-426.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2011 Citation: Noling, J.W., A.W. Schumann, and M. Cody. 2010. Assessing field distribution, crop impact and Sting nematode in Florida strawberry. Proceedings Annual International Research Conference On Methyl Bromide Alternatives And Emissions Reductions. Orlando, Florida. November 2-5, 2010:461-465.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2011 Citation: Noling, J.W., David Wright, and M. Cody. 2011. Impacts of traffic pans, subsoiling tillage practices, and deep shank fumigant injection on strawberry crop growth, yield and Sting nematode control. 2011 Proceedings Annual International Research Conference nn Methyl Bromide Alternatives And Emissions Reductions. San Diego, CA. October 31 to November 2, 2011:161-166.
• Type: Journal Articles Status: Accepted Year Published: 2006 Citation: Gilreath, J. P., Santos, B. M., Motis, T. N., Noling, J. W., Jones, J. P. & Norton, J. A. 2006. "Comparing Methyl Bromide Alternatives for Soilborne Disease, Nematode and Weed Management in Fresh Market Tomato." Crop protection. 25:690-695
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2011 Citation: Noling, J.W. and M. Cody. 2011. USDA ARS Areawide Project: Large scale field demonstrations in Florida strawberry 2010-11. 2011 Proceedings Annual International Research Conference nn Methyl Bromide Alternatives And Emissions Reductions. San Diego, CA. October 31 to November 2, 2011:261-265.

Progress 10/01/05 to 09/30/06

Outputs
LAKE ALFRED,FL: Two field microplot experiments were conducted in field microplots (95 l) at the Citrus Research & Education Center in Lake Alfred, FL during spring and fall 2006. The objectives of each experiment were to evaluate: 1) single preplant applications of five formulations of methyl bromide chloropicrin, including 98/2, 67/33, 50/50, 30/70 and 100/0; 2) two plastic mulch films including a standard low density polyethylene (Pliant LDPE) and virtually impermeable mulch (Black Bromostop VIF); and 3) four soil fumigation application rates for control of the southern root-knot nematode, Meloidogyne incognita, and yellow nutsedge (Cyperus escuelentus). For the LDPE treatments, methyl bromide chloropicrin application rates of 400, 350, 350 and 320 lb per treated acre were applied for the 98% methyl bromide and 2% chloropicrin, (98/2); 67% methyl bromide and 33% chloropicrin, (67/33); 50% methyl bromide and 50% chloropicrin, (50/50), 30% methyl bromide and 70% chloropicrin (30/70) formulations, respectively. Soil fumigation rates of 100, 75, and 50% of the maximum broadcast labeled rates were evaluated for each MBC formulation with LDPE mulch. Soil fumigation rates of 75, 50, and 25 % of the maximum broadcast labeled rates were evaluated for each MBC formulation with VIF mulch. Chloropicrin treatments of 100 and 200 lb/a with both LDPE and VIF mulch were also evaluated. For each VIF treatment, a black, 1.4 mil Klerk's Hytibar VIF mulch film was installed over the microplot prior to soil injection and left in place until planting. For each MBC formulation, a 50 lb, nitrogen pressurized cylinder was separately installed to the microdispensing system to obtain appropriate dosage for each MBC formulation.. All fumigant treatments were compared with a untreated control Ruskin,FL: A single field experiment was conducted in a seep/drip irrigated commercial field near Ruskin, FL during spring 2006. The experiment consisted of two types of plastic mulch (HiLex HDPE vs. Canslit metalized), two formulations of methyl bromide/chloropicrin (67/33 and 50/50), and 4 rates of methyl bromide/chloropicrin As the commercial standard reference treatment, a black, HiLex high density polyethylene mulch (1 mil, permeation constant (PC) to methyl bromide >200 g/m2/hr) was sealed over the plant bed immediately following methyl bromide/chloropicrin application. Application rates for each formulation ranged from a low of 100 lb. of product per treated acre to 350 lb. in 50 lb. increments. Additional rates of the 50/50 formulation were included to cover the range from 75 lb. to 250 lb. in 25 lb. increments, but only under the Canslit metalized film since greater efficacy was anticipated with that film based on previous research. The high barrier mulch film used was metallic, highly methyl bromide impervious (1 mil, PC=<14 g/m2/hr) Canslit mulch film. Separate untreated controls were included for dosage comparison with each mulch film. Data collected consisted of assessments of tomato plant vigor, mortality, yield, and counts of the number of nutsedge plants which emerged through the mulch film in 30 ft of row.

Impacts
Clearly the use of the Klerks Hytibar VIF film provided much improved nutsedge control, a lower rates of methyl bromide chloropicrin application compared to LDPE mulch. Effective nutsedge control with VIF was achieved with methyl bromide rates of 50 to 100 lb/a. Chloropicrin contributed little to methyl bromide for nutsedge or nematode control. With VIF, effective nutsedge control was not apparent at methyl iodide application rates less than 50 lb/a in the field microplots. Again, chloropicrin was not observed to synergize methyl iodide or contribute to herbicidal efficacy at rates less than 140 lb/a. Based on the results of the Ruskin field study, it was apparent that the Canslit metalized film was superior to HiLex HDPE for nutsedge control with either formulation or rate of methyl bromide. Using a 50/50 blend appears to be an acceptable method of reducing methyl bromide consumption while still maintaining nutsedge control and crop production. The methyl bromide rate -breaking point- for nutsedge control varied with the film used. A porous film like the HiLex HDPE appears to require rates of 300 lb. per treated acre or more, while a highly retentive film like Canslit metalized or any of the VIF products can achieve acceptable nutsedge control with rates as low as 100 lb. of product per treated acre.

Publications

• Fumigant Synergies: The Importance of Chloropicrin. 2006. J.W. Noling and J. P. Gilreath. 2006 Proceedings of the Annual International Research Conference on Methyl Bromide Alternatives and Emission Reductions. Pg 461-466.