West Central Michigan small fruit regional report – April 29, 2014

Small fruit growers are getting ready for the 2014 fruit season, but weather conditions are slowing down their normal seasonal activities.

Winter-like conditions are still lingering around West Central Michigan. For the past seven days, daily maximum temperatures have remained below the 60s with minimum temperatures around the upper 30s. These conditions have not been suitable for the accumulation of the necessary growing degree days (GDD) for the development of most small fruit crops, such as strawberries, raspberries and blueberries. So far, the amount of GDD base 45 degrees Fahrenheit accumulated since Jan. 1 is only 125 GDD and the accumulation above 50 F is only 56 GDD.

Strawberries in Central Michigan are still in the early stages of development. The mulch has been removed and early leaf growth development has begun in early season varieties. There was some winter damage early in the season in places where the mulch was thinner, and when the snow was gone plants were exposed for several days to temperatures near below zero, causing some damage to the crowns and early foliage. For raspberries, plants that were not mowed at the end of the winter have been mowed during the past 10 days and we could see the beginning of the new growth emerging from the crowns. However, cold weather conditions are limiting the seep of the plant growth.

In blueberries, the conditions are not very much different from the previous week, although some advance in plant development has occurred thanks to some days with maximum temperatures in the upper 50s and nightly temperatures above 40 F. So far the variety Bluecrop and other early season varieties are in the bud break stage, but in south Allegan County, there are varieties already in the early green tip stage.

Taking in consideration the weather conditions and the provability of rain for the next seven days, Michigan State University Extension’s recommendations are the following: For blueberries, it is necessary to initiate the applications of fungicides against mummy berry and Phomopsis shoot and twig blight. Currently, low temperatures and long periods of wetness are creating the perfect conditions for the presence of those two pathogens. Also, growers need to take into consideration the condition of the plant. Some fields that had winter damage need immediate protection because any wound created by the winter is a port of entry for the pathogen. Recommended fungicides with dual action against mummy berry and Phomopsis are Indar and Orbit; Quilt Xcel, Ziram and Bravo are less effective, but can be used for rotation between applications. For the recommended dose, please consult the MSU Bulletin E-154 “2014 Fruit Management Guide.”

Another important issue for all small fruit growers is weed control. Snow and bad weather that prevailed much of the early spring prevented some growers from applying preemergent herbicide to control early weed problems. This is the time to initiate a weed management program, especially in blueberries. At this time, brambles are emerging from the ground and it is the right moment to initiate their control.

According to MSU Extension small fruit specialist Eric Hanson, several new herbicides have been labeled on blueberries in the last few years. However, new products take some time to learn about and understand how they are best understood. For a review of some of the newer materials and label changes for 2014, please visit the article “Blueberry weed control updates for 2014” or consult the 2014 Fruit Management Guide for details.

New spotted wing Drosophila workshop

Regarding the integrated pest management training offered to growers to improve their spotted wing Drosophila control program in 2014, there are new requests from growers that did not have the opportunity of attending the previous training offered in April. To satisfy this demand, we will be offering a new spotted wing Drosophila workshop around the fourth week of May (May 19-23). The date will be announced soon, so please check in future reports and the MSU Extension Events webpage. If you are interested in participating in this training, please contact Judy Hanson at 616-994-4548 or hanson26@msu.edu.

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