Southeast Michigan vegetable regional report – May 15, 2013

May 13 frost caused damage on vegetables crops in the southeast region.


Our area had 0.3 inches of rain in three rain events in the past week. Temperatures in the southeast ranged from 24 to 80 degrees Fahrenheit. For a period of four hours early Sunday morning (May 13), temperatures ranged from 25 to 29 F. In the following week, temperatures are forecasted to range from 50 to 79 F.

In our region, growing degree days (GDD) are a little behind when compared with the six-year average. As our GDDs increase, the key pests on several crops will become active. To focus efforts on monitoring and managing pests, Michigan State University Extension vegetable educator Ben Werling wrote an article, “Develop an IPM calendar to proactively plan for insect pest control in vegetables,” that can guide you through monitoring and management decision making.

Vegetable crops report

Last Sunday’s frost caused significant damage in warm season crops. Tomatoes, eggplants, potatoes and peppers had frost damage symptoms. Several tomato fields that had more than 65 percent of the plants affected are being replanted. Small acreage of tomato and other vegetables that were covered with frost cloth received little to no damage. Tomatoes in high tunnels are flowering and little to no frost damage was observed.

Eggplants, peppers and potatoes had symptoms of frost on 15 to 20 percent of the plants across the field, but most of the young growth remains green. The cold temperatures decimated unprotected bean transplants. Several cucurbit crops such melons, zucchinis and yellow squash also suffered frost damage.

Frost damage on (A) potato, and different degree of frost damage on
tomato: (B) moderate, (C) severe, and (D) little damage.
Photo credit: Lina Rodriguez -Salamanca, MSU Extension

Sweet corn has emerged in the early planted fields. Few plants had frost damage symptoms. Planting will continue. Sweet corn maggot overwintering adults are flying and laying eggs as the peak flight has already occurred (we reached 563 GDD base 39 F).

Cool season crops such as cabbage, broccoli, carrots, radish, onions, peas and lettuce continue to grow and no major pest problems have been observed. We have reached 419 GDD (base 43 F), which indicates cabbage maggot overwintering flies have emerged and are laying eggs. Cabbage and cole crop plantings are complete for the most part in our area. If you still have some acreage to plant, consider control measures (soil insecticide application at planting or transplanting).

Some insect problems in the greenhouse persist, particularly aphids on peppers and mites on basil.

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