Project Overview

Reports

Commodities

• Fruits: berries (blueberries)

Target Pests

• Target Pests: weeds

Practices

• Pest Management: economic threshold, monitoring/scouting, pesticides

Wild (lowbush) blueberry is an economically and culturally important crop that covers a total of 181,900 acres primarily in Maine and Atlantic Canada. Weeds are a major limiting factor to wild blueberry yield and quality across the growing region. An increase in weed species diversity has been documented in recent weed surveys in both Maine and Nova Scotia. Perennial broadleaf, grass, and sedge species of varying patch size detract from harvestable wild blueberry acreage and weed seed reduces berry quality. IPM has a central role in disease and insect management but not weed management in Maine wild blueberry production. Wild blueberry farmers make pre and post emergent herbicide applications to whole fields or use self-taught and unofficial thresholds to determine when mixed species weed patches require a control measure. Previous development of weed economic thresholds in wild blueberry focused on two weed species from an on-ground plant density perspective, concluding that there was very little tolerance for any weeds in wild blueberry fields. The research proposed here will use both the newest drone technology and “old school” walking the field to improve farmer and researcher understanding of weed coverage in wild blueberry fields. The objectives of this project are to 1) quantify the range of area covered by weeds, 2) further understand the speed at which mixed species weed patches expand, 3) educate growers on weed mapping options and methods, and 4) expand herbicide knowledge among the next generation of UMaine Extension faculty and educators. We anticipate the clearest impact of this project to be the adoption of weed mapping and therefore more precise herbicide application directly to weed patches. We predict that at least 50 farms will adopt weed mapping, each an average size of 40 acres and 20% weed coverage resulting in reduced herbicide application on 1,600 acres.

Objective 1. Determine the range of weed area coverage in wild blueberry fields using UAV (drone) images and GIS software.
Outcome: Project team and farmers will increase their knowledge and applicability of weed mapping either by aerial image or walking fields.
Impact: Farmers have a precise sense of how much of each field is covered in weeds and how those weed patches are distributed increasing the acres monitored for weeds.

Objective 2. Determine the rate of weed patch expansion using UAV (drone) images and GIS software over several years.
Outcome: Project team and farmers increase their knowledge of how fast weed patches expand.
Impact: If the farmer knew that mixed species weed patches grew an average of 2 feet per year on all sides (for example), they could begin to determine when an herbicide application or the labor to weed whack a patch was warranted based on the amount of wild blueberry lost for each year without weed management.

Objective 3. Make weed mapping accessible to wild blueberry farmers.
Outcome: Using either precision weed management with technology or simply walking a field and using the Weed Mapping Calculator, knowledge about different weed mapping methods will be available for different sized farms.
Impact: We predict that 50 fields will have a weed map created as a result of this project. Fields are an average of 40 acres, assuming an average 20% weed coverage (8 acres), herbicide reduction would be seen on 1,600 acres.

Objective 4. Improve research-based herbicide knowledge for Maine fruit and vegetable specialists.
Outcome: Extension faculty at UMaine will increase their knowledge of herbicide mode of actions, how different classes of herbicides function, and what herbicides are available for use on fruit and vegetable crops.
Impact: At least 6 UMaine Extension faculty participate in this professional development. Each faculty has an audience of at least 100 growers with whom they will share and apply their newly gained herbicide knowledge.