Progress 10/01/05 to 09/30/09
Outputs
OUTPUTS: Activities: In 2006, 2007, and 2009, 12 pesticides accepted for organic crops, and two weed management systems (grass mulch and no mulch) were tested for pest control, yield and postharvest quality of watermelon ('Crimson Sweet'). At the Lajas Ag Exp Substation in southwestern PR, each spring we conducted trials to evaluate mulching and pesticides in organic watermelon production. In winter-fall, Crotalaria juncea was grown and soil-incorporated as green fertilizer. In 2008, six pesticides with mulching and no mulching were evaluated in two watermelon cultivars ('Crimson Sweet' and 'AllSweet'). The pesticides were sprayed weekly, according to manufacturer's instructions, including a copper fungicide, Bacillus thuringiensis, B. subtilis, potassium bicarbonate, hydrogen dioxide, milk, extracts of garlic, neem, tea tree, and blends of rosemary, wintergreen, peppermint, clove, and thyme oils. Weed, insect and disease control were rated weekly. Fruit number and weight were assessed at harvest. Fruit Brix, color, and firmness were determined at harvest and two weeks after storage at 20 C. Services (counseling, training): Mabel Vega-Almodovar, a graduate student with the Horticulture Program at UPR-Mayaguez, based her MS thesis research on this project (2007-2010). Students Fuentes-Fuster, Carlos Flores-Torres, Jacqueline Halbrendt, Helena Latoni and Laura Bonilla were trained in IPM scouting, biopesticide application, assessing treatment effects, and post-harvest evaluations. Events and dissemination: Oral presentations: Meetings of the Amer. Soc. for Hort. Sci. (July 2006), Inter-Amer. Soc. for Trop. Hort. (Sept. 2006), Dominican Soc. of Agric. and Forestry Researchers (Oct. 2007), and Soc. Puerto Rican of Agric. Sci. (Nov. 2008). Posters: Meetings of the Inter-Amer. Soc. for Trop. Hort. (Sept. 2006), Northeastern Alliance Science Day (Feb. 2008), Amer. Soc. for Hort. Sci. (July 2008), Caribbean Food Crops Soc. (July 2008 and 2009), Soc. Puerto Rican of Agric. Sci. (Nov. 2008), and the Forum on Organic Agric. of the Ag Exp Stn-UPR (Jan. 2009). Results were reported and discussed with growers, extension agents, and faculty at the 2007 annual Vegetable Commodity Meeting of the Ag Exp Stn-UPR. Procedures and results were shared with undergraduate Ag students at UPR-Mayaguez in courses. The experimental site was used for demonstration and training of undergraduate and graduate students throughout the duration of the project. Products: Interest in this project prompted the development of the courses HORT 4046 (Introduction to Organic Crops) and Selected Topics on Organic Tropical Fruits (HORT 4996). Graduate student Mabel Vega-Almodovar was trained in IPM scouting, organic pesticide application, watermelon sustainable management, and postharvest evaluation techniques. She will present her thesis in May 2010. Technical Assistant Luisa Flores was trained in postharvest color, Brix, and firmness evaluations. The project has generated information that allows comparison of organic pesticide efficacy for downy mildew management in watermelon, and quantification of the impact of mulching on weed management in this crop system. PARTICIPANTS: Morales-Payan, Jose Pablo. Project PI. Brunner, Bryan, Project Co-Pi. Martinez, Sonia. Project Co-PI. Wszelaki, Annette. Original PI (left for University of Tennesee). Vega-Almodovar, Mabel. Graduate student; did MS thesis in this project. The following UPRM students participated in the project and received training in pest/disease scouting, biopesticide application, treatment effect evaluations, and harvesting and post-harvest evaluations: Fuentes-Fuster, Carlos Flores-Torres, Jacqueline Halbrendt (graduate students), and Helena Latoni and Laura Bonilla (undergraduate students). TARGET AUDIENCES: Mabel Vega-Almodovar, a graduate student at UPR-Mayaguez, started working on the project in 2007. Her MS thesis is based on research conducted within this project and addtional experiments she has performed. She has been trained in pest, weed, and disease scouting, pesticide application, experimental design, watermelon crop management, analyses of results, and presentation of results. She has been exposed to sustainable and organic principles and applications in the production of watermelon and other crops. Luisa Flores, a Technical Assistant at the Experiment Station in Lajas, has been trained in post-harvest evaluation in watermelons (color, brix and firmness evaluations). Extension agents and growers have been targeted through publications, discussions and presentations at the yearly meetings of the PR Vegetable Crops Commodity (Empresa de Hortalizas), the Puerto Rican Society of Ag Sciences (SOPCA) and other professional meetings (see list of publications). Undergraduate students at the UPR-Mayaguez have been a major target audience for this project. The PI and Co-PIs have made students aware of the existence of the project and have exposed the students to project results in the undergraduate courses 'Organic Fruit Crop Production' (a Selected Topics course taught in 2006, 2008 and 2009), and in 'Introduction to Organic Crops' (HORT 4046) to be taught in spring 2010, as well as in informal discussions related to organics. As a result, the students Jacqueline Halbrendt, Carlos Flores, Jorge Fuentes, Luis De la Cruz, Kevin Brady, and Ian Pagan started their graduate studies at the UPR-Mayaguez in sustainable/organic horticulture with the PI and/or Co-PIs. PROJECT MODIFICATIONS: There were no major changes in the implementation of the original proposal. The only deviation from the original proposal was as follows: A mid-term evaluation of the project conducted by the agricultural research authorities of UPR-Mayaguez reflected that the project was running on schedule, that the project has been well conducted and the results obtained up to that point were valuable to growers and to the agricultural and research communities. From that evaluation, the only suggestion of changes in the project was the possibility of adding treatments with new pesticides and using other watermelon varieties that have become more popular with Puerto Rican growers. Heeding that recommendation, the researchers decided to run the 2008 trial with the biopesticide treatments that were more efficacious in 2006 and 2007, reducing the number of biopesticides in half, and using two watermelon cultivars instead of only one cultivar. Because organic seed of other watermelon cultivars popular in PR could not be obtained, in 2009 we used the original treatment list (same as 2006 and 2007).
Impacts
Project mid-term evaluation: A mid-term evaluation of the project in Fall 2007 determined that the project was on schedule, well conducted, and generating valuable results. The evaluators suggested possible variations such as trying other watermelon varieties being used by local growers. In 2008 we conducted the trial with two cultivars, but went back to one cultivar because of unavailability of organic seed of other watermelon varieties favored in PR. Change in knowledge: (a) Several students and two technicians improved acquired skills in organic production and crop protection. One graduate student wrote her MS thesis on this project. (b) The results of the project indicate that mulched plots produced greater commercial watermelon yields than non-mulched plots (because of weed suppression during the first half of the season), and that there was significant difference between pesticides in terms of disease suppression and yields. Best yield results were obtained with programs of hydrogen dioxide, tea tree extract, and neem extract. Hydrogen dioxide treatment resulted in the highest yields (as much as 30% higher than in the mulched water-treated check, and 3.5-fold the yield of the non-mulched water-treated check). Plots treated with B. thuringiensis + copper fungicide showed copper toxicity symptoms and produced yields similar to or lower than water-treated check plots. Applying the other pesticides resulted in yields similar to that of the water-treated check. Treatment effects on postharvest fruit attributes were generally inconsistent between years, but some treatments tended to affect internal coloration or pulp firmness. (c) The results of the project have expanded the knowledge for growers' decision making for protection of organic watermelon, and for researchers' decision making for future research. Changes in conditions. Safer food supply and cleaner environment. This project was the first one at the UPR-Mayaguez to explicitly focus on organic agriculture research. Valuable information was generated in terms of treatment efficacy and post-harvest impact. Awareness of the project and its implications has prompted other faculty members to engage in organic research. This project addressed the need of developing efficient sustainable/organic production systems for horticultural crops in the tropics, thus supporting safer and cleaner food production systems. Development of human resources. An important outcome/impact of this project is the increased awareness of several students, faculty and research assistants on the subject of organic food production and research, and their training in the skills necessary for conducting this type of research. These faculty members have formed a group working on the organic theme, and we have received a grant from NRCS and another from Southern Region-SARE to work on organic/sustainable systems; hence, faculty are developing in the organic area, which was unheard of before this project started. Two other grant proposals to SARE are pending. The undergraduate students have gone into graduate studies in organic/sustainable agriculture.
Publications
- Wszelaki, A.L. and Brunner, B. 2006. Alternatives for pest management in a tropical organic watermelon production system. HortScience 41:1080.
- Wszelaki, A. and Brunner, B. 2006. Creating a more sustainable watermelon production system in Puerto Rico. Inter-American Society for Tropical Horticulture Program and Abstract Book Annual Meeting, San Juan, Puerto Rico, Sept. 2006 (P17).
- Roque, S.M., B. Brunner and Wszelaki, A. 2006. Alternativas para el manejo de malezas en la produccion de sandia organica tropical (Alternatives for weed management in tropical organic watermelon production). Inter-American Society for Tropical Horticulture Program and Abstract Book Annual Meeting, San Juan, Puerto Rico, Sept. 2006 (P70).
- Vega-Almodovar, M., Morales-Payan, J.P., Martinez-Garrastazu, S.L., Brunner, B., Toro, J. and Flores, L. 2007. Effect of mulching and organic pesticides on watermelon yield in a transitioning organic system (Efecto de cobertura de suelo y pesticidas organicos en el rendimiento de sandia en un sistema de transicion organica). SODIAF (Dominican Society of Agriculture and Forestry Researchers) Program and Abstract Book Biannual Meeting, Santo Domingo, Dominican Republic (P 9). October 2007.
- Morales-Payan, J.P. 2009. Experiencias en un proyecto de investigacion con sandias en un sistema en transicion organica en Puerto Rico. Resumenes del Foro de Investigacion y Educacion en Agricultura Organica. EEA UPR-RUM. Gurabo, Puerto Rico (P 13).
- Vega-Almodovar, M., Morales-Payan, J.P., Martinez Garrastazu, S., Roman Paoli, E., Brunner, B., Flores, L., and Toro, J. 2009. Impact of mulching and biopesticides on Cyperus rotundus tuber populations in organically-managed watermelon plots. Puerto Rican Society of Agricultural Sciences Program and Abstract Book Annual Meeting. Hato Rey, Puerto Rico. November 2009 (P 19).
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Activities: Sunnhemp was planted between the 2007 and 2008 watermelon crops. At flowering, sunnhemp was incorporated into the soil as a soil green fertilizer and enhancer. Following the recommendations made by the mid-term reviewers (late 2007) the watermelon experiment scheduled for 2008 was conducted with two watermelon varieties (instead of only one variety as in 2006 and 2007), five pesticides accepted for organic production (including those with best performance in 2006 and 2007) plus a control (untreated check), and two weed management systems (grass mulch and no mulch). These combined treatments (varieties x pesticides x mulching) were evaluated were evaluated for foliar disease control, yield and post-harvest quality of organically-grown watermelons ('Crimson Sweet' and 'Allsweet'). The pesticides were sprayed weekly, according to manufacturer's instructions, and included commercially available formulation of hydrogen dioxide, a garlic extract, a neem extract, a tea tree extract, and Bacillus pumilus. Weed, insect and disease control (%) were rated every week. Commercial and non-commercial fruit number and weight) were determined after harvesting the fruits at end of the season. Mentoring: In 2007, a graduate student with the Department of Horticulture of UPR-Mayaguez, Mabel Vega-Almodovar, started as her MS thesis project based on the research. She has continued with the project and is expected to defend her thesis in August 2009, including the results of the 2007-2009 experiments. Events and dissemination: Oral presentation at the anual meeting of the Society of Ag Sciences of PR (SOPCA) in November 2008. Posters presented at the meetings of the (1) American Society for Horticulture Science (ASHS), Orlando, FL, July 2008, (2) Caribbean Food Crops Society (CFCS) in Miami, FL, July 2008, (3) Northeastern Alliance Science Student Meeting, Mayaguez, PR, February 2008. In addition, we shared resultas with undergraduate and graduate Ag students at UPR-RUM in the Fruit Crops and Organic Fruit Crops courses taught by Dr. Morales-Payan at UPR-RUM. Products: the student Mabel Vega-Almodovar has been trained in pest/weed/disease scouting, organic pesticide application, watermelon sustainable management and post-harvest evaluation techniques. In the summer of 2008 the graduate students Jacquline Halbrendt and Ricardo Albarracin, and the undergraduate students Carlos Flores and Laura Bonilla participated in the evaluations as well.. The technical assistant Luisa Flores has been trained in post-harvest color, brix and firmness evaluations. Technical assistant Juan Toro has been trained in application of organic pesticides and weed management in organic production. We have generated information that facilitates comparing the efefficacy of pesticides allowed for organic management of downy mildew and Alternaria blight in watermelon, and quantifying the impact of mulching on weed management in organically-grown watermelon. PARTICIPANTS: Morales-Payan, Jose Pablo. Project PI. Brunner, Bryan, Project Co-Pi. Martinez, Sonia. Project Co-PI. Vega-Almodovar, Mabel. Graduate student; She is doing her MS Thesis in Horticulture with some of the results and experiences derived from this Project. TARGET AUDIENCES: Mabel Vega-Almodovar, a graduate student at UPR-Mayaguez, started working in the project in 2007. Her MS thesis is based on research conducted within this Project. She has been trained in scouting of pests, weeds, and diseases, pesticide preparation and application, experimental design, watermelon crop management, and analysis of results. More importantly, she has been exposed to sustainable and organic principles and applications to the production of crops such as watermelon. Luisa Flores, a Research Associate at the Experiement Station in Lajas, has been trained in post-harvest evaluation in watermelons (color, brix and firmness evaluations). Juan Toro, a Research Assistant at the Experiment Station in Lajas, has been trained in organic pesticide preparation and application, as well as in weed management in organic systems. Graduate and undergraduate students in Agricultural Sciences at UPR-Mayaguez have shown a strong interest in organic/sustainable horticulture, becoming a natural and ample target audience for this project. Because of their awareness of this project, two UPR-Mayaguez undergraduate students, upon graduation in 2008, became new graduate students with Dr. Morales-Payan, with the intention of being trained in organic/ecological systems and conducting research in projects similar to this one. Results of this project have been shared with UPR-Mayaguez students in formal classroom sessions as well as in informal discussions related to organic production and protection of organic crops. We preceive that this Project has had a very important role in attracting undergraduate students at UPR-Mayaguez towards undegraduate research mini-projects and/or towards graduate studies in organic/ecological/sustainable agriculture. We foresee this trend of more students becoming interested (and acting upon their interest to become graduate students focussed in organic horticulture) will continue in 2009, thanks, at least in part, to the existence of this project and our outreach efforts. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Outcomes/Impacts: This project addresses the need for developing efficient sustainable/organic production systems for horticultural crops in the tropics. It also addresses the impact of protection practices on post-harvest produce attributes. We are generating valuable information on treatment efficacy and post-harvest impact. We are preparing several publications based on this information, some of which may be used for extension to pass on to growers. We are also using this project as a teaching aid for undergraduate and graduate courses relating to organic agriculture at the UPR-Mayaguez. We have an extensive collection of numerical data and pictures of weed, pest and disease pressure on organic watermelon, and a collection of pictures of external and internal appearance and other post-harvest variables that will be used for several publications and educational and reference material in courses, research, and extension activities. Our graduate student (Mabel Vega-Almodovar) is working on her MS thesis using this project as the basis. The researchers in this project have forged a closer collaboration, particularly with regard to organic production subjects, and we foresee that we will continue working as a team in organic horticulture. Because of Dr. Morales-Payan's involvement in this project, he was invited to be a Co-PI in an organically-managed sunnhemp proposal, which was approved by Southern Region-SARE and is currently being implemented at the Lajas substation in PR.
Publications
- Vega-Almodovar, M., J. P. Morales-Payan, S. Martinez-Garrastazu, & B. Brunner. 2008. Organic management of weeds, diseases, and pests in watermelon in Puerto Rico. HortScience 43:1251-1252. Vega-Almodovar, M., J. P. Morales-Payan, S. Martinez-Garrastazu, & B. Brunner. 2008. Impact of mulching and alternative pesticides on watermelon yield and quality in an organic transitioning system in Puerto Rico. Abstracts of the Northeastern Alliance for the Graduate Education and the Professoriate (NEAGEP) Science Day. Mayaguez, PR. Page 22.
- Vega Almodovar, M., J. P. Morales-Payan, S. Martinez Garrastazu, B. Brunner, E. Roman Paoli, J. Toro, and L. Flores. 2008. Influence of alternative pesticides and mulching on fruit yield and quality of organically-grown watermelon. Abstracts of the Society for Agricultural Sciences of Puerto Rico (SOPCA) 34:13. Vega-Almodovar, M., J. P. Morales-Payan, S. Martinez-Garrastazu, & Bryan Brunner. 2008. Organic watermelon yield is affected by alternative pesticides and mulching. Abstr. Caribbean Food Crops Soc. 44:88.
- Mabel Vega-Almodovar, J. Pablo Morales-Payan, Sonia Martinez-Garrastazu, & Bryan Brunner. 2008. Evaluation of alternative pesticides and mulching for organically-grown watermelons in Puerto Rico. Proceedings of the Caribbean Food Crops Society 44: (in press).
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Activities: In between the 2006 and the 2007 experiments we had the plots fallowed or covered with sunnhemp, which was later incorporated as a green fertilizer. The experiment scheduled for 2007 was conducted successfully: Twelve pesticides, accepted for organic production, and two weed management systems (grass mulch and no mulch) were evaluated for pest control, yield and post-harvest quality of organic watermelons ('Crimson Sweet'). The pesticides were sprayed weekly, according to manufacturer's instructions and included a traditional copper-based fungicide, biological control agents, potassium bicarbonate, hydrogen dioxide, milk, and garlic, neem, tea tree, and combinations of rosemary, wintergreen, peppermint, clove, and thyme oils. Weed, insect and disease control (percentage) as rated every week. Crop yield (commercial fruit number and weight) as determined, after harvesting three times, at the end of the season. In general, mulched plots had higher commercial
watermelon yields than non-mulched plots, because of weed suppression during the first half of the season. When we applied B. thuringiensis + copper fungicide (a treatment commonly used by growers), yield was the lowest among both mulched and non-mulched plots, including the water-treated check. The highest yield was found when hydrogen dioxide was applied to plants growing in mulched beds (26% higher than in the mulched check and 340% higher than in the non-mulched check). The results are encouraging and together with the results from the 2006 experiment have provided us with a clearer picture of the treatment effects. Mentoring: In 2007, a graduate student with the Department of Horticulture of UPR-Mayaguez, Mabel Vega-Almodovar, started her MS thesis project based on the research which she is helping conduct in this project. Events and dissemination: We gave an oral presentation of the results during the Biannual Meeting of the Dominican Society of Agriculture and Forestry
Researchers (SODIAF) in Santo Domingo, Dominican Republic, October 2007. Also, a poster was prepared for the Northeastern Alliance Science Student Meeting to be presented by student Mabel Vega-Almodovar in Mayaguez, in February 2008. Presentations are also planned for the 2008 meetings of the American Society for Horticulture Science (ASHS) and Caribbean Food Crops Society (CFCS), both to be held in Florida. Results were shared with undergraduate Ag students at UPR-RUM. Results were also reported and discussed with growers, extension agents and researchers during the 2007 annual Vegetable Cluster Meeting of the Agriculture Experiment Station-UPR (at Juana Diaz). Products: Student Mabel Vega-Almodovar has been trained in pest/weed/disease scouting, organic pesticide application, watermelon sustainable management and post-harvest evaluation techniques. Technical assistant Luisa Flores has been trained in post-harvest color, brix and firmness evaluations. Also generated has been
information that allows researchers to compare efficacy of organic pesticides for downy mildew management in watermelon, as well as to quantify the impact of muching on weed management in this crop system.
PARTICIPANTS: Morales-Payan, Jose Pablo. Project PI. Brunner, Bryan, Project Co-Pi. Martinez, Sonia. Project Co-PI. Vega-Almodovar, Mabel. Graduate student; She will base her MS thesis on this project.
TARGET AUDIENCES: Mabel Vega-Almodovar, a graduate student at UPR-Mayaguez, started working in the project in 2007. Her MS thesis will be nased on research conducted within this project and addtional experiments she will perfform. The student has been trained in pest, weed, and disease scouting, pesticide application, experimental design, watermelon crop management, analysis of results, and has been exposed to sustainable and organic principles and applications to the production of crops such as watermelon. Luisa Flores, a Technical Assistant at the Experiement Station in Lajas, has been trained in post-harvest evaluation in watermelons (color, brix and firmness evaluations). Because of the interest of UPR-Mayaguez undergraduate students in organic/sustainable horticulture, they have been a major target audience for this project. In this effort, students have been made aware of the existance of the project and have been exposed to results in classrooms and informal discussions
related to organics. As a result, several students have indicated their interest in pursuing graduate studies in sustainable/organic horticulture with the project researchers, and in 2008 (while still undergraduates) two of them will conduct small research projects related to this project: (1) study of impact of our treatments on nematode diversity and populations in the soil, and (2) effect of selected organic pesticides and mulching on yield and grade of a different watermelon variety).
PROJECT MODIFICATIONS: There has been no major change in the original proposal. A mid-term evaluation of the project conducted by the agricultural research authorities of UPR-Mayaguez reflected that the project is running on schedule, that the project has been well conducted and the results obtained so far are valuable to growers and the agricultural and research communities. From that evaluation, the only suggestion of changes in the project related to the possibility of adding treatments with new pesticides and using other watermelon varieties that have become more popular with Puerto Rican growers. So far, the researchers of this project have decided to run the 2008 trials as they were originally outlined in the proposal. Additionally, we will implement the suggestions of the evaluation pannel as separate trials, in addition to the regular project experiments, in a fashion that allowes for comparisson or complementarity between trials. Thus, the original project will not change,
but we will do related research that will help us understand better the results of the project.
Impacts
Outcomes/Impacts: This project addresses the need for developing efficient sustainable/organic production systems for horticultural crops in the tropics. It also addresses the impact of protection practices on attributes of post-harvest produce. Valuable information is being generated in terms of treatment efficacy and post-harvest impact. Such information is likely to be ready for active extension efforts (directed to growers) in the Fall of 2008. In addition, we are using this project as a teaching aid for undergraduate and graduate courses relating to organic agriculture at the UPR-Mayaguez. We are amassing an extensive collection of numerical data and pictures of weed, pest and disease pressure on organic watermelon, as well as pictures of external and internal appearance and other post-harvest variables that will be used for several publications and educational and reference material in courses, research, and extension activities. A graduate student (Ms. Mabel
Vega-Almodovar) is working on her MS using this project as her thesis research; two undergraduate students will conduct special research projects related to H-405. Closer collaboration has resulted among the researchers working in the project. We expect to continue working as a team in organic horticulture. Also, because of our involvement in this project, there is interest from similar research groups to work with us in related projects. Two proposals are currently submitted to SARE, one from the University of Florida-Gainesville, another from the University of Georgia-Tifton. Results of project evaluation: A mid-term evaluation of the project in Fall 2007 determined that the project was on schedule, well conducted and generating valuable results. The evaluators suggested possible variations such as excluding pesticides that gave poor results in both 2006 and 2007 and testing other pesticides, as well as trying other watermelon varieties being used by local growers.
Publications
- Vega-Almodovar, M., Morales-Payan, J. P., Martinez-Garrastazu, S. L., Brunner, B., Toro, J. and L. Flores. 2007. Effect of mulching and organic pesticides on watermelon yield in a transitioning organic system. SODIAF (Dominican Society of Agriculture and Forestry Researchers) Biannual Meeting Program and Abstract Book, Santo Domingo, Dominican Republic. (Page 9).
- Vega-Almodovar, M., Morales-Payan, J. P., Martinez-Garrastazu, S. L., Brunner, B. 2008. Impact of mulching and alternative pesticides on watermelon yield and quality in an organic transitioning system in Puerto Rico. NorthEast Alliance (NEA) Science Day, Mayaguez, PR. February 2008 (submitted).
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Progress 01/01/06 to 12/31/06
Outputs
In this trial twelve alternative products, within two weed management systems (grass mulch and no mulch), were evaluated for pest control, yield and postharvest quality of organic watermelons (cv. Crimson Sweet). This experiment was arranged in a split plot on a randomized complete block design with four replications per treatment (weed management) and sub-treatment (alternative products). The watermelons were planted in late May on raised beds with 60-cm within row and 1.5-m between row spacing. The alternative products were sprayed weekly, according to manufacturer's instructions; included were a traditional copper-based fungicide, biological control agents, potassium bicarbonate, hydrogen dioxide, milk, garlic, neem, tea tree, and combinations of rosemary, wintergreen, peppermint, clove, and thyme oils. Weed, insect and disease control (% control) were rated weekly. Fruit were harvested from late July through August and fruit quality (firmness, soluble solids) and
yield were evaluated. Weed control was significantly greater in the no mulch treatment, as early in the season these plots could be hoed by hand, whereas nutsedge easily penetrated the grass mulch treatment. The combination of copper with Bacillus thurengensis (Bt) controlled weeds more effectively than the control (water only), as did garlic extract and combinations of rosemary, wintergreen, peppermint, clove, and thyme oils. Insects (mainly aphids and cucumber beetles) did not present a significant problem in watermelon production, although the copper + Bt treatment had the greatest incidence of aphid damage compared to that with all other treatments; this treatment, however, had a significantly lower incidence of disease than the other treatments. Downy mildew was the predominant disease and decimated the foliage late in the season, except with the copper treatment. Disease pressure was also greater in the no mulch treatment compared to that in the mulch treatment, likely because
of inoculum splash from the bare soil. Fruit quality parameters tended to differ among treatments, including firmer fruit in the hydrogen dioxide treatment and sweeter fruit in the potassium bicarbonate treatment. Weed treatments affected fruit quality, as well, with significantly sweeter fruit in the mulch treatment, but significantly heavier fruit in the no mulch treatment. The no mulch treatment also had significantly higher yields than the mulch treatment. Whereas the control tended toward the highest marketable yield of the alternative products, the copper + Bt treatment tended toward the lowest marketable yield, because of plant phytotoxicity from the copper early in plant development. Although none of the products tested should be relied upon as the sole means of managing pests, those with efficacy could be integrated into organic management programs.
Impacts
Despite the fact that the body of organic farming research continues to grow, little has focused on tropical systems. Pest management in tropical systems provides challenges beyond those of conventional production. Because of differences in temperature, daylength, rainfall, and humidity versus those aspects of a temperate climate, organic producers in the tropics face year-round pest pressure. Weed management is essential for the production of high quality watermelons, but can be difficult when herbicides are not permitted. Weeds also serve as a source of inoculum for disease organisms and a habitat for insects. Many products have been advertised for disease and insect control of these pests in organic production systems; most have not been adequately evaluated in independent, replicated trials. Additional work is needed to provide more sustainable alternatives to conventional pesticides and provide information to organic growers on the efficacy of the resources
available and their effects on postharvest quality. This project addresses the high-priority objective of 'Appraisal and evaluation of practices of handling of pests (weeds, diseases and insects) in watermelon'. Additionally, it speaks to enhancing tropical organic research and creating a more sustainable production system for watermelon.
Publications
- Roque, S.M., B. Brunner and A. Wszelaki 2006. Alternativas para el manejo de malezas en la produccion de sandia organica tropical (Alternatives for weed management in tropical organic watermelon production). Proceedings of the Interamerican Society for Tropical Horticulture (In press) (Abstract).
- Wszelaki, A.L. and B. Brunner 2006. Alternatives for pest management in a tropical organic watermelon production system. HortScience 41:1080 (Abstract).
- Wszelaki, A. and B. Brunner 2006. Creating a more sustainable watermelon production system in Puerto Rico. Proceedings of the Interamerican Society for Tropical Horticulture (In press) (Abstract).
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Progress 01/01/05 to 12/31/05
Outputs
During the first two months of this project, materials were procured for the project and the experimental site was chosen. Planting for the first season will occur in early April.
Impacts
Pest management in tropical organic production systems provides challenges beyond those of conventional production. Due to differences in temperature, rainfall, and humidity versus a temperate climate, organic producers in the tropics face year-round pest pressure. Weed management is essential for the production of high quality watermelons, but can be difficult when herbicides are not permitted. Weeds also serve as a source of disease inoculum and a habitat for both beneficial and detrimental insects. Many products have been advertised for pest control in organic production systems, most of which have not been adequately evaluated in independent, replicated trials. Additional work is needed to provide more sustainable alternatives to conventional pesticides and provide information to growers on the relative efficacy of the resources available and their effects on crop quality. Here we are studying the efficacy of 12 alternative products for pest control, within two
organic weed management systems, and comparing the yield and postharvest quality of the watermelons produced. While none of the products or strategies should be relied upon as the sole means of managing pests, those with demonstrated efficacy may be used in integrated management programs for organically-produced crops. This project addresses the high-priority objective of 'Appraisal and evaluation of practices of handling of pests (weeds, diseases and insects) in watermelon'. Additionally, it speaks to enhancing tropical organic research and creating a more sustainable production system for watermelon.
Publications
- No publications reported this period
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