Southeast Michigan vegetable regional report – June 26, 2013

The weather is forecasted to be a combination of warmer temperatures and rainfall, which can result in extended periods of increased moisture. Scout for diseases and use preventive sprays.

Weather

Our area received about 2 to 4 inches of rain, with 2 inches recorded at the Petersburg Enviro-weather station. Temperatures in the southeast ranged from 61 to 89 degrees Fahrenheit with an average of 76 F, according to Enviro-weather. In the following week, temperatures are forecasted to range from 62 to 84 F, with high chances of rain every day through Saturday, June 29.

Current growing degree days (GDD) recorded at the Petersburg station and the southeast area.

 Enviro-weather station

Current GDD base:

42 F

45 F

50 F

Petersburg

1,450

1,236

912

Hudson

1,432

1,221

899

Commerce Township

1,282

1,082

783

Romeo

1,306

1,105

800

Average of stations in this region

1,367.6

1,160.9

848.5

Average 5 years Petersburg station

1,576

1,331

965

(Data summarized from Enviro-weather)

The weather forecast is a combination of warmer temperatures and rainfall, which can result in extended periods of increased moisture. Some pathogens can be spread within a field by rain splash, and the increased moistures combined with warmer temperatures can result in important disease outbreaks. Scout your fields regularly for disease symptoms and apply protective fungicide spray to protect healthy and new growth.

Vegetable crops report

Tomato, pepper and potato plants are flowering. The late blight forecast for the Petersburg/Dundee Enviro-weather station reports low severity values (DSV=4, as of June 25, 2014) and show green risk (lowest labeled rate of protectant fungicide recommended – seven day interval, according to www.lateblight.org). To get personal recommendations visit the Late Blight Risk Monitoring website and enter the date of emergence.

Potato leafhopper numbers have increased in potato fields. Low numbers of thrips have been observed in pepper fields. Aster leafhoppers continue to be present, but in low numbers in carrot fields.

Variegated cutworm first generation larvae are hatching – look for any damage in the field. Remember, cutworms in general have a wide range of vegetable hosts they can feed from, including potatoes, tomatoes, cucurbits and cole crops, among others.

Cabbage caterpillars are active. Keep in mind there are products that are efficacious to control caterpillars in cole crops that have low impact on beneficial insects. For more information, visit Michigan State University Extension specialist Zsofia Szendrei article on managing caterpillars in cabbage.

Cucurbit crops continue to grow. Fields have been staggered planted and plants are flowering or bearing fruit. Symptoms of angular leaf spot were observed in pumpkin and squash fields.

No cucurbit downy mildew has been observed in southeast Michigan or the rest of the state. However, cucurbit downy mildew was confirmed in the state of Maryland this week.

Squash vine borer emerged on June 21. Currently, moths are flying and laying eggs. Scout fields for eggs and damage. The MSU Extension publication E0312 “2013 Insect, Disease and Nematode Control for Commercial Vegetables,” provides insecticide options.

Sweet corn plants have tassels and about 20 to 30 percent of plants in early fields have silks. Low risk of corn earworm continues according to www.insectforecast.com, but traps set up and monitoring is needed as silks are present in the field. European corn borer is present in sweet corn fields (Photo 1).

European corn borer damage
Photo 1. Damage caused by European corn borer larvae. In additional to the “shot-hole” damage in the leaves, larvae cause tunnels in the stalk as shown in this picture. The stalk has been peeled with a knife to show a tunnel and a larva inside. Photo credit: Lina Rodriguez-Salamanca, MSU Extension

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