East Michigan vegetable regional report – May 18, 2016

Multiple frost advisories and spotty frost events in our region over the last week put many growers in a holding pattern, but conditions should improve.

A well-pruned indeterminate tomato with two main leaders. Photo: Ben Phillips, MSU Extension.
A well-pruned indeterminate tomato with two main leaders. Photo: Ben Phillips, MSU Extension.


Drier conditions and higher temperatures are ahead for the next week, which will put many growers in high gear after the 1-inch or more rainfall we acquired over the weekend in many places, and frosty mornings in some places.

The following table 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 May 18, 2016


Degree Days (+ added from last week)

5-year average

Rainfall (+ added from last week)

5-year average


173 (+39)


4.69 (+1.60)



185 (+41)


2.23 (+0.98)



187 (+41)


2.89 (+1.14)



165 (+39)


3.01 (+0.86)



209 (+43)


3.95 (+1.43)



127 (+34)


3.29 (+1.16)



159 (+40)


3.48 (+1.43)



192 (+40)


3.57 (+1.07)



149 (+36)


3.01 (+1.51)



I took a trip to the northern part of the eastern region this week. One community supported agriculture (CSA) farm will be opening its public market Saturday, May 21, with hydroponic bok choi and lettuce, and soil-grown radishes, kohlrabi, spinach, garlic chives and green onions. Honey, maple sugar, soup mixes and custom-labeled canned goods will provide additional variety.

Broccoli and cabbages under fabric low tunnels inside hoop houses are knee-high. Radishes and kohlrabi under the same conditions are getting close to harvestable.

The heading cole crops have grown leggy under these season extension systems for one grower. The double coverage of fabric low tunnel plus dual layer hoop house plastic reduced light transmission and wind. Wind will help make plants sturdy and stocky, and newer transplants and seedlings will develop regularly once temperatures rise and the sides can be opened and covers removed for a cross breeze.

The fabric low tunnels have been providing excellent cabbage maggot control, as can be seen by the adult flies dying on top of the covers and the healthy plants underneath. A lighter row cover will work better for light transmission and provide similar cabbage maggot exclusion, but row cover thickness decisions are really based on temperature. Under a plastic hoop house, row covers may not need to be as thick as field planted cole crops.

Large field acreages that experience cabbage maggot pressure can be managed with Lorsban. However, Lorsban is under review by the Environmental Protection Agency (EPA) for groundwater contamination, so growers should consider trying some of the alternative products on smaller areas when possible. These include Verimark and Coragen. They cost more, but work well.

Sweet onions are nearly all in the ground. Lorsban soil drench can be used as a soil drench for onion maggots after plants are established, but it is more effective at planting.

Sweet corn is still being seeded, but plastic-covered plantings are much farther along. Plastic should be coming off some fields late this week and early next week. Purdue University trapping stations caught their first corn earworm of the year in May. There were two northeasterly weather patterns that presented a low risk of migration on Insect Forecast May 9 and May 11 that probably carried that first flight up to Indiana traps. Any moths that blow in this early will likely just be chewing on leaves.

Greenhouse tomatoes are setting more fruit. Indeterminate tomatoes need continual pruning. Look for new suckers below the lowest set of flowers and snap them off before they reach the diameter of a pencil. If they get larger, they should still be removed, but will leave a bigger wound. Remove the lowest leaves completely as they discolor. Focus on creating two main stalks.

Field tomatoes are sitting and waiting for warmer weather. The fabric low tunnels were important over the last seven days as we have had multiple light frosts across the region.

Melons and summer squashes are making their way out to the fields under vented plastic low tunnels and hot caps.

Potatoes are still going in when conditions allow.

Beans and peas are being seeded in fields, or have been seeded and are up to 6 inches tall in hoop houses with good drainage.

MSU Extension fruit educator Bob Tritten is finding strawberries remained at 20 percent bloom for most farms, as bloom has been in a holding period this past week. Flower trusses and new leaves continue emerging from the crown. Most strawberry growers have frost-protected a least once in the last week. Strawberry clipper or clipped buds have been seen at several farms in the last few days, as have spittle bugs at a few farms. Angular leaf spot, another new disease for the week, has also been found on leaves at a few farms.

Special notes

MSU plant pathologist Mary Hausbeck is looking for problematic bacterial spot, speck and canker outbreaks in tomatoes to run copper resistance trials. Please contact your local MSU Extension vegetable educator to arrange for a visit or shipment.

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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