East Michigan vegetable update – July 5, 2017

Corn earworm are being caught right away this year.

I will be on a trip to Salt Lake City and Indiana from July 6–17. Please refer to my colleagues Ben Werling, Ron Goldy, Fred Springborn and Marissa Schuh in my absence.


The table below shows growing degree-days (GDD) base 50 degrees Fahrenheit since March 1, rainfall (inches since April 1) accumulations and soil temperature ranges (Fahrenheit over the last week) to date from Michigan State University Enviro-weather stations in the region.

Rainfall and GDD totals as of July 5, 2017


GDD (+ added from last week)

GDD 5-year average

Rainfall (+ added from last week)

Rainfall 5-year average


735 (+ 139)


8.15 (+ 1.26)



772 (+ 128)


7.67 (+ 2.29)



864 (+ 140)


10.72 (+ 1.65)



812 (+ 133)


10.21 (+ 2.15)



790 (+ 135)


6.98 (+ 0.06)



796 (+ 123)


6.85 (+ 1.65)



709 (+ 129)


13.76 (+ 3.77)



793 (+ 135)


8.96 (+ 1.51)



799 (+ 144)


7.57 (+ 0.91)



695 (+ 128)


8.34 (+ 1.73)



Sweet corn plantings are finished in most places. Some of the first ears were hitting markets in southwest Michigan this week, with some resale across the state.

I caught six corn earworm in one night in Tuscola County. From the Midwest Vegetable Production Guide: “…treatment is justified if fresh green silks are present and moths are being caught in pheromone traps. In general, the higher the moth catches, the shorter the interval between sprays. If fewer than five moths are being caught per night, a five-day spray interval should be adequate. As moth catches approach 50 to 100 per night, a two- to three-day spray interval would be more appropriate. Determining the spray interval exactly depends on many factors, including how much damage you can tolerate, the crop’s value, and the cost and effectiveness of the insecticide. Stop treating for corn earworms when 90 percent of the silks are brown.”

Pickles are at various stages and some are starting to bloom. Machine harvests will start soon. Michigan State University Extension’s plant pathologist Mary Hausbeck’s downy mildew recommendations for 2017 suggests at least a three-product rotation of Gavel 75DF, Orondis Opti SC, Ranman 4SC, Zampro 4.4SC and Zing! SC. Each material needs to be tank-mixed with Bravo Weatherstik or Mancozeb.

Watermelons and cantaloupes are setting fruit. The largest I saw was 3 inches in diameter. See pickle section for fungicide recommendations. Growers should alternate those products with powdery mildew products like Quintec, Torino or Rally. Some bacterial issues were evident on some farm visits last week, and treflan injury was evident in one field where the boom charged at the end of the rows.

Zucchini and yellow summer squash harvest has begun. Squash vine borer is flying and laying eggs. Multiple oddball diseases are showing up at MSU Diagnostic Services from different parts of the state, from Anthracnose to Phytophthora leaf blight. Keep an eye out for powdery mildew going forward. Quintec, Torino and Rally work well for that disease.

Fresh market field tomatoes are going to market. Third ties are being strung. Hoophouse tomatoes are beginning to phase out. Late blight has been found in two processing tomato fields in Ontario, and a suspected sample was sent in from Michigan’s Kalamazoo County. Bravo and Mancozeb are good protectants against this disease.

Processing pepper transplants are all planted.

Chipping potatoes are in full bloom around the Bay. Potato leafhopper populations are very high this year. They cause an upward curling of the leaves, and also make the leaves look dried out and burnt.


The Midwest Mechanical Weed Control Field Day is Sept. 26 at the MSU Horticulture Farm. 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, Michigan. The combination of grower-focused, research-backed presentations and an amazing exhibit hall make it a can’t-miss event.

Please contact me at phill406@msu.edu or 616-901-7513 to pick up suspected disease samples from your farm, or send the diseased plant parts to MSU Diagnostic Services.

Did you find this article useful?

You Might Also Be Interested In