West central Michigan small fruit update – June 4, 2019

All crops are progressing despite cool wet weather. Cherry and cranberry fruitworms are out in blueberries.

Spotted wing Drosophila (SWD) just started emerging in west central Michigan. Preparing your IPM-SWD program is critical. Attend the MSU Extension SWD workshop on Wednesday, June 5 to be better prepared.

Weather conditions in west central Michigan, remained unchanged; cold, breezy with periods of rain. These are the same conditions that have prevailed for the past two weeks. Temperatures for the past seven days were as follows. Daily minimums were on average 48 degrees Fahrenheit, and daily maximums 68 degrees Fahrenheit. Moderate rains and drizzle over the same period left an accumulation of 0.66 to 1.10 inches of rain. The highest precipitation occurred around the Fennville-Grand Junction, MI area.

Because of these weather conditions, Growing Degree Day (GDD) accumulation varied from 335 to 452 GDD. There is a GDD accumulation difference of almost 100 GDD between Van Buren and Ottawa County. This differential GDD accumulation is reflected on the development of small fruit crops. Development of small fruit crops in counties north of Allegan is a week or more away from what is seen in Van Buren County.

Strawberries are in the green fruit stage and growers are not reporting problems, yet.

Raspberries are in bloom with some green fruits already visible.

Blueberries in Allegan and counties north of Allegan are showing different degrees of development. Early varieties like Weymouth are in the green fruit stage. Duke, Bluecrop and other mid-season varieties are in the petal fall stage. Elliott, Liberty and Aurora are in full bloom and beginning the petal fall.

Regarding pest problems in blueberries, the the cherry and cranberry fruitworms are out. After a delay of several days, both species are showing up on pheromone traps around the Fennville-Grand Junction area. You may need to reset the biofix staring on May 27-28 or June 3 if no insects showed up in your traps the previous week.

Below are the current forecasted events on the life cycle of both cherry fruitworm and cranberry fruitworm. Use this information as a guide to program your fruitworm control program.

Visit Michigan State University’s Enviroweather to get updated information on current and forecasted GDD accumulations. Also, check the cherry fruitworm and cranberry fruitworm models for oviposition starting period predictions.


1st adults

1st eggs

Current Degree Day accumulation (6/04/2019)

Grand Junction, MI

Fennville, MI

West Olive, MI

Cherry Fruit Worm


432 ± 15




Cranberry Fruit Worm






The other major problem for berry crops is the spotted wing Drosophila (SWD). Due to the mild winter conditions we had over the past months, we just observed the early beginning of SWD activity in the area. During the past week entomologist Rufus Isaacs’ scouting crew found the first flies on monitoring traps placed around the Fennville-Grand Junction area. On May 23, the first female was caught, and on May 30, another 10 females and 2 males were caught in the same area. Therefore, our recommendation is to be prepared for SWD management and adjust your IPM program accordingly. Below describes a meeting, an opportunity to improve your SWD management skills.

2019 Systems Approach to Managing Spotted Wing Drosophila in Berries

If you had problems in the past controlling this pest, and if you have early blueberry varieties, raspberry or strawberries we recommend you to attend the SWD training we are offering on Wednesday 5th (tomorrow) at the Southwest Michigan Research Center in Benton Harbor, MI.

The workshop will be from 9:00 am to 4 PM. And this is the best opportunity to be updated and trained to deal with this early arrival of this pest. The workshop is based on using advanced IPM tools to manage the SWD. These IPM tools translate directly to the bottom line; savings in pest control, fewer insecticide applications, and minimum crops losses due to SWD

There is a $25.00 fee for this workshop that includes materials, lunch and refreshments. Be sure to check out the workshops’ agenda and online registration.

2019 IPM Training (Spanish/English): Early/Mid-Season Blueberry pest problems

MSU Extension’s Small Fruit Team and the Michigan Food and Farming Systems (MIFFS) invite Hispanic growers, field managers and farmworkers to attend this IPM scout training to receive updates on Integrated Pest Management tools and practices for managing early and mid-season blueberry pest problems; cherry and cranberry fruitworms, stem gall wasp, and blueberry fruit rots.

This workshop will be offered on Friday June 7, 2019, from 4 a.m. to 9:00 p.m. at the Main Conference Room Lakeside Entertainment, 09921 Blue Star Memorial Highway, South Haven, MI 49090.

Training will be conducted in both Spanish and English. Simultaneous translation, English/Spanish, will be available for those that may require it. There will be 2 RUPs credits for those attending the program.

There is no cost for attending this meeting. However, to ensure an accurate handouts and dinner count, please pre-register by calling: Filiberto Villa at: 269 830-2309. Also,  you may register online for the 2019 IPM Training for Hispanic Growers.

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