East Michigan vegetable regional report – June 29, 2016

Weather has been too dry for unirrigated vegetables, especially on sandier ground.


There is a chance of rain Friday, July 1. We are far behind our five-year average rainfall accumulation.

The table below includes rainfall (inches since April 1) and degree-day (base 50 degrees Fahrenheit since March 1) accumulations to date from Michigan State University Enviro-weather stations in the region.

Rainfall and degree-day totals as of June 29, 2016


Degree Days (+ added from last week)

5-year average

Rainfall (+ added from last week)

5-year average


877 (+124)


6.59 (+0)



917 (+133)


3.50 (+0.02)



948 (+131)


4.40 (+0)



918 (+133)


4.65 (+0)



935 (+127)


5.96 (+0)



810 (+123)


5.76 (+0)



916 (+129)


5.49 (+0)



962 (+137)


4.77 (+0)



821 (+120)


7.97 (+0)



Squash vine borer did start showing up in acorn squash, zucchini, yellow squash and pumpkin this week, right on schedule. Egglaying should start within a week. Management options are covered in the MSU Extension article, “Squash vine borer biology and management.” Organic options are limited, but Entrust is one that has had some successful suppression in Ohio. Butternut squash, watermelon, cucumber and cantaloupes are not hosts for this insect. Seedcorn maggot has been an issue in some watermelon transplants.

The earliest planted pickling cucumbers are flowering. This dry weather has been impacting later plantings. Growers are setting seeds deeper to follow moisture, or fields are being skipped. Downy mildew has been reported as far north as Maryland, but not in Michigan. Our monitoring efforts for spores and confirmed cases of downy mildew can be found on the MSU Downy Mildew News site.

In onions, MSU plant pathologist Mary Hausbeck has been finding bacterial leaf blight getting out of control on some fields, despite the dry weather. This is an important disease to control early because once onion leaf tissue dies, it does not get replaced very well. The plant does not grow new leaves as rapidly as a tomato, for example.

MSU entomologist Zsofia Szendrei has found that seed maggots, including onion maggots, overwintered with high numbers, and are still an issue in some fields despite Lorsban applications. Thrips are probably enjoying this hot, dry weather. Growers should be moving to Agri-mek or Lannate at this point. Do not be discouraged if Movento plus surfactant did not eliminate all of the thrips. This is perfect thrips weather, and it will be an important year to keep up on management. The last two years were poor thrips years, and two applications of Movento were enough for the whole season in some places.

Sweet corn moths are on growers’ minds right now. I am behind the ball and do not have traps out yet. European corn borer populations have been lowered since GMO corn was introduced. Corn earworm catches have been low in Indiana, and we have not had many weather migrations. Excerpted from the Midwest Vegetable Production Guide: “For corn borers, treat during the late whorl stage if 20 percent or more of the plants show larval feeding. For corn earworms, 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.”

Strawberry harvest has wrapped up for growers in the southern reaches of the region and continues for a few more days for other growers to the north. Most growers report having a longer than normal harvest season. Renovation has begun for a few growers. MSU Extension encourage growers to water well as soon as the renovation process is complete. There has been great demand for pick-your-own and ready-picked strawberries this season. Strawberry sap beetles are starting to be a problem on some farms. I am just starting to see a few new plantings with curled leaves from potato leafhopper feeding.

I’ve been getting calls about herbicide damage. Take pictures if you can and email them to me at phill406@msu.edu so I can see them or pass them on. There is not much you can do to “cure” the plants but wait and see if they make it. It is too late for many crops to be replanted. If a conflict arises, you can file a formal complaint with the Michigan Department of Agriculture and Rural Development (MDARD) at 1-800-292-3939. An herbicide application drift can be seen spreading from field edges from the direction of the wind. If it was tank contamination, the damage will follow the path of the sprayer.

I have also gotten calls about herbicides not working. Weeds get tougher in dry weather because they put on a thicker, waxy cuticle to prevent dehydration, and won’t translocate post-emergent herbicides. This is especially true of grasses. Pre-emergent herbicides usually need some moisture to activate, and weeds will escape control without 0.25–0.5 inch rain or irrigation. This has been the case for pre-emergent herbicides across the state.

Special upcoming events

On July 13 from 6-9 p.m., commercial vegetable growers are invited with their families to join the MSU Extension vegetable specialists at the new Helena Chemical facility north of Imlay City, Michigan, for a mid-summer vegetable clinic, social dinner and a tour of the new facility. Please RSVP with the number of eaters to Angelique Rooney at 989-758-2500 by July 6. The dinner is fully sponsored by Helena Chemical and Farm Bureau Insurance, and RUP credits have been requested from MDARD.

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

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