Southeast Michigan vegetable regional report – August 3, 2016

Despite the season’s dry conditions, harvest continues for many vegetables in our region.

A male western bean cutworm moth, which will be seen in pheromone bated traps. Note the wing markings. Photo: J. Obermeyer.

A male western bean cutworm moth, which will be seen in pheromone bated traps. Note the wing markings. Photo: J. Obermeyer.


While rain events this weekend have alleviated some of the immediate need for water, precipitation is still below average. Recent rainfalls have been incredibly variable by location, with Adrian, Michigan, receiving nearly 4 inches of precipitation in the span of a few hours while other areas received none.

It is important to remember that even though precipitation has been limited, the high humidity may still allow for the spread of plant disease, especially fungi. Even phytophthora, which is typically associated with wet conditions, can still take hold if there is enough water present for plant growth.

The table below presents rainfall (in inches) for the Michigan State University Enviro-weather stations in southeast Michigan.

Rainfall amounts in southeast Michigan

Weather station

Rainfall in last week

Rainfall in since April 1














Sweet corn harvest continues. High numbers of western bean cutworm have been reported in southern Michigan, and peak flight has occurred in southern and central Michigan. I have seen these moths present in traps in Monroe County. MSU Extension recommends scouting late-season corn that is in the pre-tassel stage. Western bean cutworms lay eggs in clusters on the leaf surface, making scouting easier, and the moths are large and have a somewhat distinct appearance. More information on scouting can be found in “Scouting corn for western bean cutworms” by MSU Extension. Field corn is currently silking in many areas, which can lead to a surge in the number of corn earworms present in traps. Because of this, treatment thresholds in sweet corn for this pest change, going from one moth per trap per night to 10 moths per trap per night.

Potato harvest will begin soon. Black leg has been found in some southern Michigan counties and there was a suspected case in our region, so monitor for this disease that can make storing potatoes difficult. Late blight was also found in southwest Michigan. For tracking the pathogen and the current risk status in your area, check out MSU’s Late Blight Risk Monitoring website, which tracks the disease spread and predicts risk for different areas in Michigan. For more information about recognition and treatment of this disease, see “Late blight confirmed in potatoes in northern Indiana July 6, 2014” by MSU Extension.

Processing tomatoes are coming along nicely and harvest will begin in mid-August. Processing and fresh market tomato growers should keep an eye out for late blight, which can affect tomatoes in addition to potatoes. Tips for identification and management can be found in “Late blight threatens Michigan tomatoes” by MSU Extension.

Banana pepper harvest has begun.

Cabbage harvest has also begun and no issues have been reported.

Watermelon and muskmelon are coming along nicely, with harvest starting on some farms. Minor problems with aphids and spider mites have been reported. Spider mites do well under hot conditions, and the first sign of spider might damage is yellow spotting on the leaf where females have laid eggs.

Squash and cucumber harvest continues. Powdery mildew has appeared on squash and zucchini, so keep an eye out for this fungus, which first appears on the underside of older leaves.

Growers of cucurbits, especially cucumbers, should be scouting for downy mildew. This fungus can be devastating and prevention is key in protecting crops. Downy mildew has been reported on cucumbers in the Thumb region. The appearance of downy mildew can vary depending on the crop, and reporting downy mildew is key in preventing the disease from devastating entire regions, as people can ramp up preventative measures if cases are confirmed. For more information and the latest updates on downy mildew, visit MSU’s Downy Mildew News.


On Aug. 27, there will be a Breakfast on the Farm event in Hartland, Michigan. Tickets are free and can be picked up at various locations in southeast Michigan.

For women involved with farms who want to increase their knowledge in regards to farm management and finance, Annie’s Project is offering classes at the Lenawee County Extension Office starting Sept. 15. For more information and registration, visit the Adrian Annie’s Project event page.

For growers interested in organic vegetable production and management techniques, the Zilke Farm in Milan, Michigan, will be hosting an Organic Vegetable Farm Twilight Meeting from 6-8 p.m. on Sept. 8.

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