Recipient Organization
UNIVERSITY OF MAINE
(N/A)
ORONO,ME 04469
Performing Department
School of Food and Agriculture
Non Technical Summary
Wild (lowbush) blueberry (Vaccinium angustifolium) is an economically and culturally important crop that brings an annual average of $22.2 million to the state of Maine. Conventional, high-input management practices have been studied to increase yield in the wild blueberry system for decades.As the wild blueberry market and farming community changes, lower-cost and reduced pesticide use are of interest from both large and small producers. The goal of this project is to further develop cultural integrated pest and crop management tactics for wild blueberry farmers by focusing on the impact that nutrients have on pest pressure. Tip midge (Dasineura oxycoccana) is an emerging pest while grass and broadleaf weeds are an age-old pest complex in the wild blueberry system. Foliar fertilizers and soil amendments have not been evaluated for efficacy. Through replicated field research trials, the relationship between nutrient application and pest pressure will be documented and analyzed. Pest and nutrient management research will be incorporated to educational events and publications through Calderwood's research-based education program. The long term goal of this work is to improve the economic feasibility of wild blueberry production while maintaining ecological resilience.
Animal Health Component
80%
Research Effort Categories
Basic
(N/A)
Applied
80%
Developmental
20%
Goals / Objectives
The overarching goal of this project is to provide existing and new research-based integrated pest and crop management knowledge for the wild blueberry growers of Maine. By fine-tuning cultural management tools and investigating wild blueberry nutrient management, we will improve the economic and environmental sustainability of wild blueberry farming in Maine.OBJECTIVES1. Weed Survey: A. Document the current weed community in wild blueberry fields. a. Investigate integrated pest management of spreading dogbane.2. Cultural Weed Management: A. Explore cultural weed management tools including tine weeding, cover cropping and hand weeding.3. Tip Midge: A. Measure the impact of conventional fertilizer on the presence of tip midge.4. Nutrient Management: A. Evaluate the efficacy of foliar fertilizers currently advertised to wild blueberry growers. B. Identify effective and economical sources of organically approved soil amendments for wild blueberry.a. Explore whole field mulching as an organic matter amendment5. Outreach: A. Integrate nutrient and pest research into the UMaine wild blueberry education program through presentations, meetings, production guide, new factsheets, and online content. B. Expand the accessibility of research-based knowledge to wild blueberry farmers and stakeholders in Maine.
Project Methods
PESTS Weed Survey: Objective: Document the current weed community in wild blueberry fields. A weed survey of wild blueberry fields began in 2019 and will be continued. Ten fields have been completed so far. Fields are located throughout the growing region of Maine and represent a variety of management styles. Prune fields will continue to be visited twice, once to capture early summer weeds (June-early July) and a second time to capture late summer weeds (August-early September). A randomly selected one acre section of each field will be surveyed using an "inverted W" transect pattern. Five, 1m2 quadrats will be placed on the ground along each transect for a total of 20 quadrats per site per visit. GPS coordinates will be taken using a handheld GPS unit at least in the four corners of each sampled area. Followingmethods from Mueller-Dombois and Ellenburg 1974, blueberry cover, broad leaf weed cover, grass cover, and individual species cover were all ranked on a 0-6 severity scale where each ranked number correlates to percent coverage. One soil sample will be taken from each site and analyzed by the UMaine Soil Testing Lab for pH and nutrients. Spreading dogbane (Apocynum androsaemifolium) is a common weed in wild blueberry fields. Due to its wide canopy and broad leaf, this weed competes with wild blueberry. Beginning in 2020, a dogbane weed whacking experiment will be conducted to determine how many times a grower would need to cut spreading dogbane to significantly reduce its presence. There will be four replications of 3 treatments which include dogbane not cut (control), cut once, cut twice, and cut three times. Evaluation measures will include dogbane height, number of dogbane stems per patch, proximity to other dogbane patches, and growth stage of dogbane.Cultural Weed Management Trial: Objective: Explore cultural weed management tools including tine weeding, cover cropping and hand weeding. Cultural methods of weed management will be compared at Blueberry Hill Farm Experiment Station in Jonesboro, ME within a randomized complete block experimental design replicated 6 times. Tine weeding, cover cropping and hand weeding will be explored as alternative weed management strategies for both organic and conventional wild blueberry systems. A 7ft wide Lely tine weeder will be used to weed plots in the early spring under the following treatments 1) tine in prune year once, 2) tine in prune year twice, 3) tine once in prune year and once in crop year, 4) tine in crop year once, and 5) tine in crop year twice. Winter-kill cover crop plots will be planted during the last week of August in both prune and crop years to allow 6 weeks of growth. Common oat grass and pearl millet have been chosen for their weed competition, winter-kill, and acid tolerant characteristics. Cover crop treatments will include the following: 1) common oat at low rate (150lbs/acre), 2) common oat at high rate (250lbs/acre), 3) pearl millet at low rate (30lbs/acre), 4) pearl millet at high rate (40lbs/acre). There will be one treatment with overlap: tine weeding one time in the spring and cover cropping with oats (150lbs/acre) in the fall. Weed and cover crop data will be collected in all plots using a 1m x 1m quadrat before and after each weed management tactic occurs. Within each quadrant percent blueberry cover, cover crop, grass and broadleaf weed cover will be recorded.Tip Midge Study: Objective: Measure the impact of fertilizer on the presence of tip midge. Stems affected by tip midge will be monitored at three on-farm sites across the wild blueberry growing region. Using a randomized complete block design, replicated 6 times in each location, eight stems per plot will be selected for in-depth study. Four stems showing tip midge damage, and four without will be flagged and labeled with a zip tie. Half of the plots in each location will have chicken manure applied and half will have no fertilizer applied. Treatments will be compared for tip midge severity. Measurements of bud counts and stem heights will be takenduring bud development. The following season, flower and berry counts will be taken prior to harvest. Berry yield and sugar content will be measured from all stems flagged.NUTRIENT MANAGEMENT Objectives: A. Evaluate the efficacy of foliar fertilizers currently advertised to wild blueberry growers. B. Identify effective and economical sources of organically approved soil amendments for wild blueberry. Both soil and foliar samples will be taken at the site location for this study at Blueberry Hill Farm (one location). Products and controls will be tested in prune and crop fields in a randomized complete block design. Each treatment will be replicated eight times in 6' by 30' plots. Products will be applied at the recommended rate according to the label or company representative. Diammonium phosphate (DAP) will be included as the grower standard control at the recommended rate by the University of Maine Soil Testing Lab based on foliar test results from 2018. Products that are recommended for vegetative and bud development will be applied as prune year products and those recommended for flowering and fruit development will be applied as crop year applications. Prune year product evaluation began in 2019 and will continue one-time monthly June through September for 4 years. The DAP fertilizer treatment will be applied one time as a broadcast application by hand in June. Products will include but are not limited the following: SeaCrop 16 (NorthAtlantic Kelp), Salvador, Agro-Phos, Kal-T, Poma (Agro 100), and NanoGro (AquaYield). B.Field Set Up. Soil amendments will be applied at two rates at each of three organic farm locations. Farms selected will be representative of three scales (small, medium, and large) and the three major wild blueberry growing regions (Mid-coast, Ellsworth, and Downeast) in Maine. The experimental design will be a randomized complete block replicated six times. Each plot is 6' by 30' (180 ft2 ) where a total of 54 plots and 9 treatments located at each site. Materials will be applied at the recommended time and rate according to the label when available and soil amendments that are bulk material without a label will be applied according to recommendations from University of Maine Extension Compost specialist. Measurements will be taken to capture the impact of these products overtime on crop productivity and pest pressure. Products will include but are not limited to Cheep Cheep (chicken manure North Country Organics), top soil (Cobscook Blend, Coast of Maine Compost), and softwood bark mulch (Mark's Disposal). Data Collection Methods for Objectives A and B: Pest Pressure. Two 0.37 m2 quadrats will be placed and flagged for repeated pest and plant growth measurements within each plot for repeated measures throughout the season. Blueberry crop cover, presence of weed species, insect and disease pressure will be measured by counting the number of infested stems or the number of weeds within each quadrat. Weeds will be counted into two groups: grass and broadleaf.Crop Productivity. Blueberry crop cover, stem height, and number of buds per stem will be measured in September of prune years and in May of crop years, flower counts, yield and quality will be measured. Height, bud count, flower count, and yield will measured on the same 8 stems per quadrat. Crop quality will be measured in crop years by taking brix and acidity using a hand held ATAGO PAL-BX/ACID2 master kit.Data Analysis. Blueberry crop cover, pest incidence (weeds, insect pressure and disease), and water holding capacity will be statistically compared using ANOVA in JMP (JMP®, Version 14.3) across all fertilizer/amendment treatments (α = 0.05). The effects of the fertilizer/amendment treatments on blueberry health, evaluated as a function of stem height and bud count will also be statistically compared using a one-way ANOVA in JMP (α = 0.05).