Southwest Michigan vegetable update – July 3, 2019

Higher temperatures result in increased plant growth.

Symptoms of Stewart’s wilt on corn
Symptoms of Stewart’s wilt on corn. Photo by J.K. Pataky, University of Illinois at Urbana-Champaign,


The 50-degree Fahrenheit degree-day units are at 892 for 2019 compared to 1,146 for 2018 and 1,123 for the five-year average. We had around 0.25 inch of rain or less across the area during the week. Temperatures ranged from 83 F to 90 F for highs and 60 F to 69 F for lows. Normal highs for this time of year are near 81 F.

Crop reports

Yellow squash, zucchini and slicing cucumber harvest volume has increased as more fields have come into production. Direct seeding of new plantings continue. Watermelon and cantaloupe continue to flower and growth has responded well to increased temperatures.

Early sweet corn is in tassel. Growers can expect harvest compression even though there was staggered planting times. Stewart’s wilt has been detected. This is a bacterial disease carried by corn flea beetles and is controlled by controlling the beetle. Most commercial seed is protected with an insecticide. Symptoms were in an organic planting. Stewart’s wilt causes internal browning and curling of leaves in the whorl and they will not open properly. A white striping of the leaves later in the season is also a symptom.

Final plantings of tomatoes have been made. Final pepper plantings will also go in over the next week or so on white plastic. Staking and tying continues in both crops. Many early pepper fields are now in bloom and some have set fruit on small plants. This is a concern since small plants with a fruit generally have limited production. If this happens to small acreage producers, consider removing that first fruit so you get more plant growth. This is not economical for large acreage producers who might be able to induce the flower to fall off through increased nitrogen applications.

Earliest snap beans will be harvested by the weekend for minimal local sales.


We are entering herbicide drift season. Tomato growers need to be especially concerned since tomatoes are so sensitive. If you have a corn or soybean field near your tomatoes, have a discussion with the producer and let them know the sensitivity of your crop and encourage them to be careful when they apply their herbicide. Also, be careful not to self-inflict the damage. That has happened to more than one producer. Please refer to “What to expect when filing a pesticide complaint with MDARD” from Michigan State University Extension for more information on reporting pesticide drift damage.

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