Spotted Wing Drosophila (SWD) Updates
Spotted Winged Drosophila (SWD) is an invasive pest native to eastern Asia which first appeared in wild blueberry fields in Maine last year. We know that the SWD maggots have been found in fruit and can produce a significant crop loss if not controlled. It is important to monitor for this pest in your own field (see http://umaine.edu/blueberries/factsheets/insects/spotted-wing-drosophila-update/). Wild blueberry growers can also receive timely updates on SWD fly captures from Cooperative Extension on our email listserv. If you are not receiving the wild blueberry listserv updates, fill out the “Wild Blueberry Newsletter” form at http://umaine.edu/blueberries/newsletters/ and be sure to include your e-mail address. Also, be sure to keep us abreast of any e-mail and mail address changes so that you don’t miss out on timely and important information. You may also check the “Wild Blueberry Blog” at http://umaine.edu/blueberries/blog/. If you do not have a computer, your local library can help with web access. Currently, this pest has no natural enemies in Maine to keep populations in check. However, fruit growers across the country are successfully managing SWD and maintaining fruit quality.
Wild Blueberry Crop Prospects for 2013
Maine Crop – Dave Yarborough, University of Maine Cooperative Extension
The blueberry plants in Maine had a long fall and a mild winter, so plants had plenty of buds and a great potential crop. We had an initially dry spring, and very few infection periods for mummyberry disease so most growers were able to protect plants with just one fungicide application. There was a 10-day stretch of rain at the end of May which coincided with peak bloom and this year we also observed many fields with high levels of botrytis blossom blight, which was also seen last year in Maine. We had good conditions at the beginning of pollination, so some fields had adequate to good pollination but pollination weather deteriorated at the end of May and early June so set was not very good in the coastal Downeast fields unless there were high levels of bees in the field. Tony Jadzack’s best estimate for bees contracted to pollinate wild blueberries is 74,772 hives. This is a “new” record for hives used to pollinate Maine’s blueberry crop. In 2012 (a now broken record) 69,428 hives were shipped to Maine for blueberry pollination. Hives originated from operations based in: AR, CA, FL, GA, KS, LA, MA, ME, NC, NJ, NY, PA, SC, and TX. Tony indicated that if the trend continues and the weather and the blueberry market cooperate, we could approach 80,000 hives next year. In Jonesboro, we received 3.47 and 5.75 inches of rain in April and May respectively and had 7.3 inches in June, with many areas receiving record amounts, so moisture has been more than adequate which has provided for both good blueberry and weed growth. It is very uncertain with the uneven pollination and with the threat of SWD and the push for an early harvest what the final crop will be this year. But the weather has been cool so there is little stress so far on the plants and with a good fruit set in some areas of the barrens and if we get adequate moisture for the remainder of the summer, the crop in Maine could still be about average at 85 million pounds.
Quebec Crop – Samuel Cote, Quebec Wild Blueberries Inc.
In most areas in Quebec we had good snow coverage over the winter. In early spring, we did not notice any winter injury. By the end of April to beginning of May, we had warm weather for a week that started development earlier than usual. Then we had a period of continuous cold and rainy conditions which stalled development back to normal. In early bloom stage towards the end of May, we had a couple of nights of frost. Then, we had cold and rainy conditions until the middle of bloom, so we had about one week of good conditions for pollination. Unfortunately, toward the end of bloom, in the third week of June, we had another night of frost. Then we had more cold and rainy conditions until the beginning of July, at which time we are finally getting warmer weather. We noticed highest rates of disease, such as mummyberry, botrytis blight and others, than we have ever seen in Quebec in most fields. We are expecting a below average crop and are estimating about 50% of damage from frost and disease. If we get adequate weather, we believe that we could still have about 35 million pounds of wild blueberries in Quebec, which includes a good crop in the forest of about 10 million pounds.
Nova Scotia Crop – Peter Burgess, Perennia
Nova Scotia had a more traditional start to the year compared to 2012. We had a dry April and early May which allowed some growers to get away with one application for Monilinia control. The weather during early bloom, for the bulk of the province, was quite good, with several warm flying days. As we got into later bloom rainy cool conditions began, but there were still some flying days that allowed for a decent pollination. Nova Scotia again brought in 4400 hives from Ontario through the import permit program. There is also an effort to increase the size and number of Nova Scotia beekeeping operations, and although numbers are not finalized, there was a significant increase in available hives in 2013. The use of Bumble bee quads is also increasing. Nova Scotia looks to have a decent fruit set and yields should be similar to last year of around 40 million pounds. The major challenges we are starting to see as we head into July are increased weed growth due to the moisture and increased levels of botrytis. Botrytis has been increasing over the last several years as we get denser canopies combined with wet weather. The biggest concern for growers as we head into harvest is SWD. There is a large effort among growers and researchers to monitor for this pest in 2013.
New Brunswick Crop – Mike Melanson, New Brunswick DAAF
Growing conditions for the vegetative fields in 2012 were generally good. A number of insects, blueberry gall midge and other sucking insects, killed the growing tip and branching occurred and set buds in the fall. The control of leaf rust with fungicide application helped plants set the fruit buds. Although little snow covered the fields for a period during January, only minor incidents of winter injury were reported. Conditions in late April were warm and dry. Monilinia blight pressure was low, however daily rain during mid-May created an infection period for Monilinia blight. Fortunately, only a few fields have some losses due to Monilinia blight. Rain continued throughout early bloom and resulted in some fields with poor fruit set. Better weather was recorded in later fields; however pollination is mediocre throughout the province. NB growers imported fewer honey bee colonies from Ontario and Quebec, and it is suspected the total number of colonies is less than in 2012. A number of growers are reporting Botrytis blight. Damage is more severe in fields with no fungicide application. In collaboration with the fruit growers of NB, a monitoring program for the detection of Spotted Wing Drosophila was put in place. Traps have been set up throughout the province in early crops such as strawberry, raspberries and early blueberry fields. More traps will be established in blueberry fields as the season progresses. If there is adequate moisture for the rest of the season, and growers manage SWD accordingly, it is expected that most regions will harvest an average crop of 35 million pounds.
PEI has had a good start to the 2013 growing season for wild blueberry. There was very little winter kill overall, although there were some isolate exceptions in exposed areas. The weather was more ‘typical’ compared to 2012 season which was very early. Very little variation in crop development across fields resulted in many growers scrambling to apply fungicides in a timely manner. This resulted in good Monilinia blight control. Several infection periods occurred for Monilinia blight and growers were able to protect the crop in a timely manner.
Although pollination weather appeared to be less than ideal, there is good fruit set and fields look to be well positioned to produce a good crop for 2013. There were higher than normal numbers of bumblebee quads used this year as a result of some high over winter losses in one large beekeeping operation. The use of bumblebee quads contributed to the high pollination levels during the less than ideal pollination weather. Changes to PEI’s Bee Health Regulations permitted the entry of honey bees from regions other than Nova Scotia for the first time. Although no significant loads of honey bees entered PEI for pollination due to lack of availability in provinces such as Ontario, beekeepers did take advantage of sourcing nucs and queens from Ontario and Saskatchewan. A small load of colonies did enter from New Brunswick.
Insect pressure has been very low so far this season. Although Botrytis blight is typically not a big problem for PEI growers, 2013 proved to be the exception with higher than normal levels of Botrytis reported. The big focus this year will be monitoring for spotted wing drosphila (SWD). An extensive network of monitoring fields has been established between the PEI Department of Agriculture & Forestry, Agriculture & Agri-Food Canada, Bragg Lumber Co. and Wymans to help growers identify the appearance of SWD and time that first insecticide treatment. SWD trap captures will be reported to growers on a weekly basis for the major growing regions. So, PEI is expecting an average crop of 11 million pounds for 2013.
Wild blueberry fact sheets, past newsletters, contacts, resource links, calendar of events, and more can be found at the wild blueberry website: www.wildblueberries.maine.edu
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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