2012 Newsletters - Wild Blueberry Newsletter – June 2012
Organic Blueberry Meeting
The University of Maine is sponsoring an organic wild blueberry meeting on Tuesday, June 12th at 1:00 p.m. at the Blue Hill Berry Company in Penobscot. Here are the directions from Route 1 in Orland: take Route 15 South then a right onto the intersection of 199 South to the village of Penobscot. Take a right at the intersection of Route 199 and 175 – the farm is located at 95 Dunbar Road and is on the right about 2.5 miles from the intersection. Look for a green mail box with 95 on it and proceed up the driveway. This is an opportunity to get an update on the research progress from the University and to network with your fellow organic wild blueberry growers.
Improving Your Wild Blueberry Yields – Fertility Management
Over the years I have reminded you to take a leaf sample from your field in July to determine the health of your plants and the need for fertilizer but I have not emphasized the benefits of this practice. Unlike most garden crops which get their nutrients each year directly from the soil, the wild blueberry has an underground stem called a rhizome which has stored nutrients, so using a soil sample will not give an accurate measure of the plant’s needs. A leaf sample taken at the tip tieback stage will allow you to determine if your plants are deficient in nitrogen (N) or phosphorous (P). The addition of fertilizers such as Diammonium Phosphate (DAP) have been shown to increase yields, see Fact Sheet 225, Lowbush Blueberry Nutrition Series: Fertilizing with Nitrogen & Phosphorus, http://umaine.edu/blueberries/factsheets/production/fertilizing-with-nitrogen-phosphorus/, however excessive fertilizers will stimulate weeds, so it is important to take a sample to determine you plant’s exact needs.
The leaf standards that we use were developed by Trevett in 1972. However, leaf nutrient standards have been updated in an Agriculture/Agri-Food Canada fact sheet by Sanderson in 2011 entitled “Nova Scotia Wild Blueberry Leaf Nutrient Ranges”, http://www.agrapoint.ca/Fact%20Sheets/Horticulture/Fruit/Blueberry/Blueb_Leaf_Nutr_ENG-WEB.pdf and new standards based on an analysis of leaf tissues and yields over the past 30 years are being developed by Dr. John Smagula at the University of Maine and will be incorporated in the recommendations from the University of Maine testing lab and available in a new Wild Blueberry Fact Sheet. So be sure and follow the instructions in Wild Blueberry Fact Sheet 222, Lowbush Blueberry Nutrition Series: Leaf & Soil Sampling Procedures, http://umaine.edu/blueberries/factsheets/production/leaf-soil-sampling-procedures/ to determine your plant’s nutrient needs and to get fertilizer recommendations.
Soil samples are generally taken at the same time but only to determine the pH. Reducing the soil pH to 4.0 will reduce weed competition and the need for herbicides while still allowing your wild blueberries to grow and yield well. For more information see Fact Sheet 254, Cultural Management pH, http://umaine.edu/blueberries/factsheets/management/254-cultural-management-ph/.
Improving Your Wild Blueberry Yields – Postemergence Weed Control
Preemergence applications of herbicides will not control all of your weeds especially if you just used Velpar and you have resistant weeds or if there was several inches of rain after you made the application. Fortunately there are now more options to control these weeds after they have emerged. There are several herbicides that will control grasses applied to them at 4 to 6 inches, but usually two applications are required to get all of the emergence of annual grasses and a higher rate is required for perennial grasses. See Fact Sheet 235, Postemergence Grass Control for Wild Blueberries, http://umaine.edu/blueberries/factsheets/weeds/235-postemergence-grass-control-for-wild-blueberries/. Rushes and sedges might look like grasses but will not be controlled by grass herbicides and require two treatments of Callisto for effective control. Many smaller herbaceous broadleaf weeds will also be controlled by this treatment. See Fact Sheet 256, Mesotrione Use in Wild Blueberries, http://umaine.edu/blueberries/factsheets/weeds/256-mesotrione-use-in-wild-blueberries/. Be sure to scout your fields in June to determine if you need additional treatments to maintain weed control and yields.
David E. Yarborough
Extension Blueberry Specialist
Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.
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