- Fruits: berries (cranberries)
- Crop Production: organic fertilizers
- Education and Training: demonstration, extension, on-farm/ranch research, participatory research
- Pest Management: botanical pesticides, integrated pest management
- Production Systems: organic agriculture
Since cranberries are grown in wetlands and farms are located in areas of dense suburbanization, the industry is motivated to adopt effective pest management strategies that promote sustainability. A small but interested group of growers want to produce organic cranberries in the Northeast, but data and recommendations for managing pest populations are lacking. We propose to evaluate if corn gluten meal (CGM), a natural product approved for use in organic farming that has been successfully used in other systems, could be an adequate method of preemergence weed control on cranberry farms. We propose conducting both greenhouse and field studies. The greenhouse experiment will evaluate potential phytotoxicity of CGM on cranberry plants prior to the establishment of the field study. The field study will be established at a commercial farm to provide data under typical farming conditions. The staff of the Weed/Integrated Pest Management (IPM) Program at the Cranberry Station has the experience and expertise to generate applied research data and provide outreach activities to the grower community. Results will be presented to growers at an annual cranberry management meeting, as well as disseminated by newsletter and website articles. We will conduct a survey about the current state of pest management for organic cranberries and we will host a bogside workshop at the study site. The evaluation of CGM as a preemergence weed management option would have a dual benefit in that this strategy could also easily fit into a conventional cranberry pest management plan as well as an organic one.
Our outreach will include a bogside workshop, presentation of the results at an Extension meeting, which will be archived at a digital repository, as well as inclusion in written Extension publications such as newsletters and management guides.
Project objectives from proposal:
The proposed work would be a pilot study to evaluate the efficacy of CGM for preemergence weed control on young cranberry bogs that have not yet achieved a continuous mat of vegetative cover (i.e., areas of bare soil are present that support germinating weed seeds) and to guide further investigations into the use of CGM in cranberry. The study will use what is currently known about CGM based on studies from turf and other crops and expand that knowledge to research trials on commercial cranberry farms. It will extend a novel weed control method from turf and annual crops to a perennial crop system and could potentially inspire further studies.
We will address the problem by establishing two sets of experimental plots on a commercial farm that was planted less than 3 years ago. In the early spring of 2013, these plots will be hand weeded to remove existing weeds and to establish a uniform baseline between plots, and then treated with a granular application of CGM. Susceptibility of weeds to CGM may vary by species so plots will be monitored on a monthly basis to evaluate which weed species are present in each plot, and the relative cover of each weed. Prior to cranberry harvest, all the weeds will be collected from each plot and biomass will be identified, dried and weighed.
The grower collaborator will provide the research area on the farm, provide general farm maintenance, and serve as the host for the proposed bogside workshop. The grower will assist with the initial establishment of the plots and will be present during CGM application. The grower will provide input on how to best use CGM in a commercial situation. The grower will assist UMass Cranberry Station staff in networking with other organic cranberry growers. The staff from the Cranberry Station will be responsible for treatment applications, data collection and analysis, outreach programs, and other communications with the industry.
A granular CGM product formulated for organic agricultural use will be purchased from a commercial supplier (McGeary Organics, Inc., Lancaster PA). We propose conducting both a greenhouse and a field study. A greenhouse experiment, utilizing the facilities at the UMass Cranberry Station in East Wareham, MA, will be conducted using potted cranberry plants to evaluate any potential phytotoxicity of CGM or rate response of CGM on cranberry plants. Although the greenhouse study is scheduled to run for 5 months, it will be started with enough lead time prior to the field study to assess any phytotoxicity issues (i.e., injury to cranberry). Based on previous work with herbicides, symptoms usually show within 14-21 days, so we anticipate that any issues will be observed and corrected prior to treating the field trial. We do not anticipate any phytotoxicity issue based on work from other crops but propose to start the greenhouse study early enough to make adjustments if needed. The field study will be established at a farm in South Plymouth, MA to provide data on CGM performance under typical farming conditions. We will also conduct a phone survey to assess the current state of pest management for organic cranberry production. To improve networking between Extension and organic growers, we will host a bogside workshop at the study site towards the end of the summer.
Rooted cranberry plants established from cuttings approximately six months prior to treatment will be used in the greenhouse test. Each pot will contain a single cranberry plant that has sufficient leaf material to allow for visual phytotoxicity assessment. We will count the number of stems and measure stem length for each pot to determine the baseline plant status. Three rates (untreated, low, and high) of CGM will be applied to potted cranberry plants in the greenhouse study, and treatments will be replicated four times. The low rate will be 20 lb/acre (manufacturer’s recommendation), and the high rate will be 40 lb/acre. CGM will be applied to individual pots using a shaker. Cranberry plants will be visually evaluated for damage monthly for 5 months. At the conclusion of the study, the number and length of stems will be determined and the plants will be removed from the pots. The aboveground portion of the plant will be separated from the roots, and both parts will be dried in an oven at 60°C for at least 3 days, and then weighed. The data will be statistically analyzed to test for differences in stem number, stem length, and cranberry biomass between the CGM treatments.
Experimental plots will be established at two sites on a commercial cranberry farm in March 2013 as a randomized complete block design. Each site will be a young cranberry planting (< 3ys since planting). Plots will be 1 m2 and marked with flags to denote their location. There will be five treatments: untreated, one application of low CGM, two applications of low CGM spaced four weeks apart, one application of high CGM, or two applications of high CGM spaced four weeks apart. Evidence indicates that CGM will effect germinating seeds for several weeks, so timings will be spaced a month apart to capture a total of 8 weeks when the majority of annual weeds will be germinating (Christians 2012). All treatments will be replicated five times per site. Plots will be hand weeded to remove all weeds present at start of the study to standardize the plots prior to treatment.
Plots will be monitored and evaluated monthly. Visual evaluations will made to document which weed species are present in each plot, and the percentage of weed and cranberry cover in each plot will be recorded. Cranberry cover will also be evaluated at the initiation and the conclusion of the study. Photographs will be taken periodically to use in outreach such as presentations and newsletters. Prior to cranberry harvest (September 2013) all weeds in each plot will be collected and sorted by species. Cranberry biomass will be evaluated by harvesting a 1-ft2 area of cranberry vines from each plot. These samples will be dried in an oven at 60°C for at least 3 days and weighed to determine weed biomass of each weed species in each plot. This information will be statistically analyzed to determine if CGM reduces the overall amount of weed biomass, which weed species it controls, which rate and frequency of treatment gives the best weed control, and if CGM affects cranberry vine coverage.
In addition to the proposed research, we also plan to obtain contact information of organic cranberry growers in the Northeast through agencies such as Bay State Certifiers and other resources. We will survey these growers to identify pest management needs and priorities, and gather information on current weed control methods and their efficacy. We anticipate the number of organic cranberry growers in the Northeast to be few, so we propose conducting phone surveys. A bogside workshop will be held at the experiment site in Southeastern MA to discuss the CGM project and current organic practices for weed management. Dissemination of the workshop date and other relevant information will be made through the UMass Cranberry Station newsletter and web site.