West central Michigan small fruit update – July 31, 2018

Blueberry harvest continue without delays with early season varieties already harvested. Bluecrop is in the second or third harvest depending on location. Growers will start harvesting Jersey fields this week.

After several weeks of summer drought and high temperatures that affected fruit quality in some early season blueberry varieties, current weather conditions have improved. Although the rain deficit continues in west central Michigan, daily maximum temperatures have remained below the mid-80s. During the past seven days, daily minimum temperatures averaged 59 degrees Fahrenheit and the daily maximum averaged 80 F. This decrease in the daily maximum temperatures helps growers to have a better control of the hydric needs of the blueberry plant at this moment.

As of July 31, 2018, drought conditions in west central Michigan at counties located north of Allegan remain severe. Cumulated precipitation since January 1 is only 15 inches with little more than 0.5 inch accumulated during the past 10 days. Conversely, counties south of Allegan have received up to 27.5 inches of rain during the same period with more than 3 inches accumulated during the past 10 days.

Drought conditions are compelling growers to provide supplemental irrigation to maintain fruit quality in mid- to late- season varieties. So far, fruit harvested is of excellent quality but yields are lower than the past season. Bluecrop fields already hand-harvested more than once are being machine harvested for processing. Harvest of Ruble fields is already underway and the harvest of Jersey fields will start this week in counties south of Allegan. Both Ruble and Jersey fruits are of excellent quality and flavor.

Regarding insect and disease problem in blueberries, it is important to take notice that fruit rots are already showing up in blueberries harvested for fresh packing. Anthracnose is one concern. Even though weather conditions have been dry with only scattered rain showers for the most part, frequent use of sprinkle irrigation to provide supplemental irrigation to fields being harvested creates conditions for Anthracnose to prosper. So, the recommendation is to be alert to the presence of fruit rots in ripe blueberries if sprinkle irrigations is in use. Maintain your fungicide application program and use the recommended fungicides at the first symptoms of disease infection. Anthracnose infected berries in blueberries harvested for fresh packing will contaminate the entire fruit lot when passing through the packing line.

For insects, spotted wing Drosophila (SWD) continues increasing in numbers in most blueberry fields being harvested. However, prevailing drought conditions have limited the reproductive potential of this pest. And even though we are seeing a steady increase in the number of flies trapped in our monitoring network, we are not seeing the amount of damage growers reported at this time in 2017. The drought effect on the SWD reproductive potential combined with a decline in the daily maximum temperatures (at or below the mid-80s), are making it much easier to manage this pest at tolerable levels. And making more effective and efficient pyrethroid insecticides that are one of the most effective tool against the SWD. However, it is important to remember; to have successful SWD control, select the best insecticide according to prevailing and forecasted temperatures and precipitation.

Save the date - August 11

Special Workshop: Spotted Wing Drosophila/ Integrated Pest Management Training & Pesticides License Test for Blueberry Growers

Michigan State University Extension (MSUE) and Michigan Food & Farming Systems (MIFFS) will host a workshop for blueberry growers on Saturday, Aug. 11, 2018, from 8:30 a.m. to 5:00 p.m. in the Van Buren County Human Services Building, East Conference Room in Paw Paw, MI. The address is 801 Hazen Street, Paw Paw, MI 49079.

Participates can also take the Restricted Use Pesticide Applicator (RUP) exam for growers who need to obtain their RUP certification or whose certification has expired. There will be a brief review of the RUP Training Manual (Private Applicator). The exam may be taken in English or Spanish. This workshop will earn 4 RUP's for growers who want to renew their Pesticide Applicator Certification Certificate (see attached flyer for the workshop agenda)

There is a $20 fee for this workshop that includes materials and refreshments. Pre-registration is required. There will be 4 RUP Recertification for attending this training. A separate fee of $50 per person (check or money order only, payable to the "State of Michigan") is required to take the exam to obtain a Restricted Use Pesticide Applicator Certificate.

For more information and pre-registration, contact either Filiberto Villa Gomez, cell: 269-830-2309, Mark Longstroth at 269-657-8213, Carlos Garcia at garcias4@msu.edu, or call at 616-260-0671. Online registration and agenda will follow soon.

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