West central Michigan small fruit regional report – May 31, 2016

Small fruit production has continued with very few problems. Recent weather conditions sped up plant growth and development in blueberries, raspberries and strawberries.

Temperatures in the region for the past seven day were in the low 80s. The average minimum temperature was 62 degrees Fahrenheit and the maximum was 81 F. There were some scattered rains in the west central Michigan region that left an accumulation of 0.5 to 1 inch of rain in some areas.

Currently, blueberries in the central region are at bloom stages ranging from the beginning of petal fall in early varieties in Allegan County to full bloom in Ottawa County and other northern counties. Few problems have been observed in blueberries. Although some of the rains that occurred during the past week helped to maintain moisture in the ground, it was not enough. Supplemental irrigation is needed to maintain a healthy crop.

Regarding diseases in blueberries, no major problems have been reported. Insects, on the other hand, are already out. Cherry fruitworm and cranberry fruitworm are flying in west central counties. In Allegan County, cranberry fruitworm started emerging during the past week, and the first application of insecticide against this pest will coincide with application against cherry fruitworms.

Fruitworm development in Michigan according to phenology models


First adults

First eggs

Current degree-day accumulation (5/31/2016)

Grand Junction


West Olive

Cherry fruitworm

238 ± 30

432 ± 15




Cranberry fruitworm

375 ± 20

460 ± 20




According to the cranberry fruitworm degree-day model on Michigan State University’s Enviro-weather, cherry fruitworm and cranberry fruitworm eggs should already be found in berry fields in Allegan and Van Buren counties. For insecticides recommended at this time, please see MSU Extension bulletin E0154, “2016 Michigan Fruit Management Guide.” An option at this time for organic blueberries and also for conventional production could be using Basillus thuringiensis (B.t.). Recommended products include Dipel and Javelin. Those products are excellent for fruitworm control when temperatures are above 70 F.

Another important pest at this time is blueberry stem gall wasp. In Allegan, Ottawa, Muskegon and Oceana counties, blueberry stem gall wasps are already emerging from last year’s galls. Females are actively searching for oviposition sites on the new growth. No insecticide should be applied at this time because bees are still working on those blueberry stem gall wasp-infested fields. Last year’s studies conducted by MSU entomologist Rufus Isaacs indicated that insecticide applications at petal fall, after the bees had been removed from the field, had good control of this insect. Some of the best results were with Lannate and Mustang Max applied right after the bees were removed from the field.

If you need assistance with your insect pest management program, including selecting insecticides or Enviro-weather, contact your local MSU Extension fruit educator or contact me at 616-260-0671 or garcias4@msu.edu.

Good Agricultural Practices (GAP) training for Hispanics

The first Food Safety Workshop for Hispanic Blueberry Growers will be Friday-Saturday, June 3-4, 2016. Training will take place at the MSU Trevor Nichols Research Center in Fennville, Michigan, and the hands-on session will take place at selected farms participating in the training. This training will facilitate growers’ compliance with the minimum requirements demanded by the FDA and buyers. Growers and farmworkers participating in this training will receive a certificate of completion of training. There will be a recuperation fee of $30 per participant that will cover materials, refreshments and lunches. For a full agenda, more information and to register, go to: Food Safety Workshop for Hispanic Blueberry Growers. You can also register by contacting Filiberto Villa at 269-830-2309 or filibertovilla@sbcglobal.net.

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