Southeast Michigan vegetable regional report – June 19, 2013

Warmer temperatures are contributing to crop development, but also insect activity. Scout fields regularly and use action thresholds to time insecticide applications.


Our area had 0.58 inches of rain on three rain events on Wednesday (June 12), Thursday (June 13) and Sunday (June 16). The past week brought the warm weather most vegetable crops needed. Temperatures in the southeast ranged from 54 to 85 degrees Fahrenheit with an average of 69 F, according to Enviro-weather. In the following week, temperatures are forecasted to range from 60 to 80 F, with low chances of rain for the following days.

The growing degree days (GDD) recorded at the Petersburg Enviro-weather station indicated the current year is behind by 131, 100 and 59 GDD base 42, 45 and 50 F, respectively (see table below), when compare with the previous five years.

Current GDD summary (data summarized from Enviro-weather)


Enviro-weather station

Current GDD base:

42 F

45 F

50 F









Commerce Township








Average of stations in this region




Average 5 years Petersburg station




The weather forecast indicates warmer nighttime temperatures and increase in humidity. This will contribute to plant development, but also insect activity and disease development. Scout your fields regularly for insect, damage or disease symptoms.

Vegetable crops report

Tomatoes, peppers, potatoes and eggplants continue to grow. The late blight forecast for the Petersburg/Dundee Enviro-weather station shows yellow risk. The Late Blight Risk Monitoring website recommends highest labeled rate of protectant fungicide. To get a personal recommendation, visit the Late Blight Risk Monitoring website and enter the date of emergence.

Variegated cutworm overwintering moths emerged June 12 and were trapped in the southwest part of the state. Remember, cutworms in general have a wide range of vegetable hosts they can feed from, including potatoes, tomatoes, cucurbits and cole crops among others. In the following week, consult Enviro-weather and scout in the early morning for larvae damage. The Michigan State University Extension publication E0312, “2013 Insect, Disease and Nematode Control for Commercial Vegetables,” provides action thresholds for every crop of interest.

Cabbage worms and diamond back caterpillars are active. Pea harvest continues and beans have started to form pods. Cucurbit crops continue to grow, some fields are flowering or bearing fruit. No cucurbit downy mildew spores have been reported in the Monroe, Mich., or Saginaw, Mich., traps. Striped cucumber beetles are active and have caused damage in zucchini and squash.

Striped cucumber beetles in squash.
Photo credit: Lina Rodriguez-Salamanca, MSU Extension

Leafhoppers are active in fields that were planted to carrots last year. However, leafhoppers in fields planted to carrots this year have not reached threshold. Thrips are active in onion fields, but the counts average between 0.4 and 0.8 thrips per plant. Continue scouting for thrips and see the MSU Extension article “Onion thrips are present in Michigan onion fields in 2013” more information on onion thrips. Warmer and dry weather will contribute to the rise of thrip populations.

Sweet corn continues to grow; early fields are staring to bear tassels. Low risk of corn earworm continues, according to, as weather patterns have not favored insect migrations the previous week. Corn rootworm risk continues to be high in Ohio, Indiana and Illinois, but not yet in our area. No corn rootworm larvae or adults have been observed.

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