2012 Newsletters - Wild Blueberry Newsletter – May 2012
Improving Your Wild Blueberry Yields – Pollination
Many times over the past 21 years that I have been publishing the Wild Blueberry Newsletter, I have emphasized the importance of good pollination as an essential part of increasing your wild blueberry crop yields. Wild Blueberries have large sticky pollen that requires insects to cross pollinate the flowers. The more visits to the flowers by bees the more seeds that form which results in larger fruit that ripen earlier and more evenly. The increase in the wild blueberry crop from 20 to 80 million pounds over the past 30 years has been paralleled by increases in the number of honeybees hives imported into Maine for pollination. It is not a coincidence that Maine uses the most honeybees, about 50 to 60 thousand hives each year, and has the highest yield per acre when compared to the Canadian wild blueberry producing areas. The graph below illustrates the increases in yield that may be expected with the increase in the number of hives, but it is from a survey conducted in 1998, so the yield on the more highly managed field of today could be more than double these yields.
Although honeybees are still readily available, for a price, there is concern about the colony collapse disorder (CCD) and the potential of future availability. Honeybees are not very efficient wild blueberries pollinators but because large numbers of bees can be brought into your fields they are still very effective in pollinating your crop. Bumblebees are now commercially available and are much more efficient but there are also much fewer bees in the quad. See Wild Blueberry Fact Sheet No. 302, Commercial Bumble Bee (Bombus impatiens) Management for Wild Blueberry Pollination, for more details in the use of bumblebees http://umaine.edu/blueberries/factsheets/bees/302-commercial-bumble-bee-bombus-impatiens-management-for-wild-blueberry-pollination/.
There are also a large number of native bees found in and around wild blueberry fields that can provide a significant amount of pollination. Two fact sheets that give details on how you can increase these pollinators are Wild Blueberry Fact Sheet No. 301, Field Conservation Management of Native Leafcutting and Mason Osmia Bees, http://umaine.edu/blueberries/factsheets/bees/301-field-conservation-management-of-native-leafcutting-and-mason-osmia-bees/ and Wild Blueberry Fact Sheet No. 630, Wild Bee Conservation for Wild Blueberry Fields, http://umaine.edu/blueberries/factsheets/bees/630-wild-bee-conservation-for-wild-blueberry-fields/. Diversifying your pollination resources will provide you with greater pollination security and ensure you get good pollination even with poor weather conditions.
Frank Drummond, our wild blueberry entomologist, is currently leading a team of researchers (Dr. Alison Dibble, botanist; Dr. Cyndy Loftin, Landscape ecologist; Dr. Sam Hanes, geographer; Dr. Aaron Hoshide, economist; and Dr. Dave Yarborough, blueberry Extension specialist; along with several graduate students) to identify the best way to increase these native pollinators and will be providing you with the results of his work when it becomes available. Meanwhile a good resource guide: Farming for Bees: Guidelines for Providing Native Bee Habitat on Farms is available for purchase or free to download on the web at: http://www.xerces.org/guidelines-farming-for-bees/.
How do you know if you have enough bees in your field? Dr. Drummond has developed a simple survey that you can use in your field to determine if you have adequate pollinators. It may be found under Schedule for Monitoring Pollinators in Wild Blueberry Fact sheet No. 204, Integrated Crop Management Field Scouting Guide for Lowbush Blueberries, http://umaine.edu/blueberries/factsheets/production/integrated-crop-managment-field-scouting-guide-for-lowbush-blueberries/.
Improving Your Wild Blueberry Yields – Leaf Spot Disease Control
With the change from burning to mowing for pruning wild blueberries, we have lost the sanitation benefit that burning provides by destroying some of the infected plant debris on the soil surface. Along with the trend of longer, warmer growing seasons, increase in leaf spot disease has increased. Septoria leaf spot will decrease the ability of the plant to make food thereby reducing the number of flower buds and fruit. Heavy infection of leaf spots, especially those resulting in early leaf drop, reduces the yield potential of the wild blueberry plant. Fungicides that will reduce this infection are found in Wild Blueberry Fact Sheet No. 219, Disease Control Guide for Wild Blueberries, http://umaine.edu/blueberries/factsheets/disease/219-disease-control-guide-for-wild-blueberries/.
NOTE: Pristine should be listed under Leaf Spot not Mummyberry in Fact Sheet 219. If you see excessive leaf spotting and leaf drop in the crop years, then fungicide applications in the non-bearing year will help reduce this infection and may improve 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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