Southwest Michigan vegetable update – July 11, 2018

Disease incidence is on the rise.


High temperatures ranged from 77 to 91 degrees Fahrenheit and lows from 56 to 71 F. There was 0.3 inch of rainfall for the week and 0.6 inch for the past two weeks. This is a big change from previous reports. The soil is drying out and irrigation is becoming necessary. The 50 F degree-day units are at 1,328 for 2018 compared to 1,331 for 2017 and 1,270 for the five-year average.

Field activity

With low rainfall, field activity has progressed at a normal pace. Final plantings of many crops will go in over the next week or two.

Crop reports

Bacterial disease symptoms have increased on tomatoes and peppers. However, confirmation has not been done at this time. Dry weather should slow spread, but be diligent with your spray program.

Peppers in general are suffering from poor growth. We are uncertain as to why this may be, but the consensus is that it is weather related. Many fields were transplanted prior to periods of hot weather. Plant mortality was high in many of the fields, with growers needing to replace a high percentage of transplants.

I am getting reports of herbicide damage on tomatoes. The plants may grow out of it depending on the level of herbicide received.

Early planted zucchini, yellow squash and cucumber fields are finished. Remove these fields as soon as possible to minimize disease spread. Some phytophthora symptoms have also been noted. Squash vine borer will still be a concern over the next week and susceptible cucurbit crops will need protection.

Early sweet corn is being harvested for local sales. Many plantings are at the silk stage, so be diligent in your control measures for corn earworm. Minor European corn borer damage has been noted on some stalks, but not enough to be of concern. Honey bees forage heavily on corn pollen, so apply safer products and at a time when bees are less active.

Hot, dry weather may lead to an increase in mite populations. Mites are easier to control when populations are low, so be diligent in scouting fields for early signs. Early infestations will be spotty, so do more than just a “windshield survey.”

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