Southeast Michigan vegetables regional report – July 10, 2013

Rain has put field operations behind schedule, including preventative fungicide sprays and vegetable transplanting for fall harvest.


The Petersburg Enviro-weather station recorded the highest amount of rain in southeast Michigan, with 4.22 inches of rain in 11 rain events (Table 1).

Table 1. Rainfall in southeast Michigan from June 26 to July 9 (data from Enviro-weather)

Enviro-weather station

Rainfall total (in.)

Hours with rainfall







Commerce Township






Average of stations in this region



Average 5 years Petersburg station



According to the NOAA National Weather Service, our weather conditions are classified as an unusual moist spell, but not as extreme as the Thumb area. In the past two weeks, we had up to 21 hours of wetness and a minimum of seven hours of wetness.

The temperatures in the southeast ranged from 58 to 84 degrees Fahrenheit with an average of 71 F. In the following week, temperatures are forecasted to range from 54 to 87 F, with a relatively low chance of rain.

Current growing degree days (GDD) recorded at the Petersburg Enviro-weather station are 1,841, 1,585 and 1,191 (GDD base 42, 45 and 50 F respectively), and are behind the five-year averages by 146.3, 115.2 and 74.5 (GDD base 42, 45 and 50 F respectively).

The frequent rain in the area impacted field operations by delaying transplanting, pesticide sprays and harvesting. Some locations received additional rainfall resulting in flooding and flooded patches in fields (Photo 1). Hail events caused damage on several crops including onions and snap beans.

Flooded cucurbit field
Photo 1. Flood in cucurbit fields. Photo credit: Lina Rodriguez-Salamanca, MSU Extension

Vegetable crops report

Tomatoes are bearing green fruit. Symptoms that resemble bacterial speck have been observed in tomatoes (Photo 2).

Bacterial leaf blight
Photo 2. Symptoms of bacterial leaf blight in tomatoes (speck to
be confirmed). Photo credit: Lina Rodriguez-Salamanca, MSU Extension

The risk of late blight at the Petersburg Enviro-weather station has accumulated 31 disease severity values (DSV) in our area. This means the weather conditions are favorable for late blight and the highest labeled rate of protectant fungicide is recommended in a minimum of seven-day intervals. According to Michigan State University Extension specialist Willie Kirk, late blight has been confirmed in neighboring states.

Cabbage harvest continues and no cabbage aphids or thrips have been observed. Due to the rain, soft roots of cabbage heads have been observed.

Cucurbit crop harvest continues. No cucurbit downy mildew has been observed in southeast Michigan. However, cucurbit downy mildew was confirmed in four Ohio counties and spore counts have increased in the spore traps in Michigan. For more information, check MSU Extension specialist Mary Hausbeck’s recent article on cucurbit downy mildew.

Early sweet corn ears continue to develop. High risk of corn rootworm is forecasted in our area and the rest of the Midwest. Keep in mind to rotate crops (avoid corn-corn in the same field in consecutive years).

Low risk of corn earworm continues, but traps have recorded above threshold corn earworm moth counts for both the Lenawee and Monroe county traps. Moderate risk of western bean cutworm is forecasted. Trap setup and monitoring is needed as silks are present in the field.

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