Southeast Michigan vegetable update – Sept. 6, 2017

Cooler temperatures slow plant development.


Below average temperatures have moved into our region over the last week, which will slow the development of many vegetables. Weather models suggest this will last until the middle of the month. The table below presents rainfall (in inches) for the MSU Enviroweather stations in southeast Michigan. Degree days (starting March 1) calculated using the Baskerville-Emin Method.

Rainfall and Degree Day Totals as of Sept. 6


Degree Days (base 50)

5-Year Degree Day Average (Base 50)

Rainfall since April 1st (inches)














Carrots are being harvested.

Fall planted cole crops have gone in and harvest continues on all cole crops. Cabbage harvest is slow on some farms, but quality and weight is reported to be good. Some sporadic incidences of tipburn have been reported to Michigan State University Extension.

Pepper harvest in ongoing. Enviroweather models predict the third generation of European corn borer began flying Sept. 2 in Deerfield, while in the more northern areas of our region, the cool weather has slowed insect development and delayed emergence.

Potato harvest continues, and will ramp up in a couple of weeks.

Some light pumpkin harvest has begun. I’ve seen a couple plantings where the pumpkins had bacterial spots on areas where the pumpkin wasn’t touching the ground, as well as some oedema. The wet weather has allowed phytophthora to progress in afflicted plantings. If you have fields where the leaves have been thinned by powdery mildew and other leaf diseases, harvest the pumpkins now and store them in a barn or another covered area to prevent sunburn.

Both processing and fresh market tomato harvest is ongoing. Some staked tomato plantings with determinate varieties are reaching the end of their life.

Sweet corn harvest is slowing down on some farms. Corn earworm populations are higher than they were for much of the season, but still in a range that is typical for this time of year, with an average of 8 moths per night being captured in my Lenawee County trap and an average of 1.75 moths per night caught in my Monroe County trap. A 3-to-5-day treatment interval is appropriate right now, and remember, when 90 percent of the silks in a field are brown, you can stop spraying for earworm. If you have had recent pickings of sweet corn that appeared to have high numbers of European corn borer, take a closer look at the caterpillars you are finding. The corn I’ve looked at has had Western bean cutworm instead of European corn borer. Western bean cutworm can be controlled with sprays, provided they are timed correctly. Keep an eye on next year’s reports for advice on this.

Sweet potatoes have sized up well, harvest is still a week or two out.

Winter squash is being harvested.

Final regular update for 2017

This will be the last regular vegetable report of the year. Contact me at any time with questions or requests for pest/disease ID sampling, either at 517-264-5309 or at I make updates regularly on Twitter at @SoutheastMIVeg.


The grower trainings mandated by the FSMA will be held in multiple locations on the eastside of the state in the upcoming months. Unless your farm is exempted by earnings or market, it is required that one person on your farm takes this training. The Produce Safety Alliance trainings are currently the only training approved by the FDA and thanks to grant funds are free to growers. I urge you to take this course now! Save the date for one of these trainings and keep an eye on the Michigan State University Extension website for registration to open:

  • Oct. 23, 2017, at the Westin Book Cadillac in Detroit, MI.
  • Nov. 1, 2017, at Cabela’s in Dundee, MI.
  • Nov. 6, 2017, at the Bavarian Inn in Frankenmuth, MI.

All trainings are from 9 a.m. to 4 p.m.

Growers with greenhouse and floriculture aspects to their farms may be interested in the attending the 2017 Greenhouse Production, Plant Health, and Marketing Conference on Sept. 13 in Lansing, Michigan. A wide range of topics will be covered, with a focus on increasing plant quality, safety, and sales. For more information, see “Register now for 2017 Greenhouse Production, Plant Health and Marketing Conference.”

The Midwest Mechanical Weed Control Field Day is scheduled for Sept. 26 at the MSU Horticulture Farm. This meeting will feature mechanical weeders from the US and Europe, as well as the experiences of farmers who use these tools. For more information and registration, see “Midwest Mechanical Weed Control Field Day.”

Hotels are filling up for the Great Lakes Fruit and Vegetable EXPO, Dec. 5-7 in Grand Rapids. The combination of grower-focused, research-backed presentations and an amazing exhibit hall make it a can’t-miss event. 

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