Southeast Michigan vegetables regional report – July 31, 2013
Harvest continues in the southeast. Dry weather has been a relief for growers and the cool nights are delaying crop development.
Temperatures in the southeast ranged from 47 to 78 degrees Fahrenheit with an average of 72 F. In the following week, temperatures are forecasted to range from 56 to 79 F. Several light scattered showers were observed with less than 1 inch of rain. The next precipitation events are forecasted for today (July 31) and Thursday (Aug. 1).
Current growing degree days (GDD) recorded at the Petersburg Enviro-weather station are 2,511, 2,175 and 1,657(GDD base 42, 45 and 50 F respectively). The cool nights from the last two weeks put us even further behind than before on the five-year average by 149, 124 and 91 (GDD base 42, 45 and 50 F respectively).
Vegetable crops report
Cabbage and sweet corn harvest continues. Corn earworm moth numbers increased from last week and are above threshold for both the Monroe County and Lenawee County traps (nine and 11 moths caught in seven days respectively). No European corn borers have been caught in the Monroe County trap. Western bean cutworm moth counts were different between the Monroe County and Lenawee County traps (12 and three moths caught in seven days respectively), but no egg masses have been observed. The risk for this insect pest is now forecasted as high in our area.
Bell peppers with symptoms of sunscald and banana peppers with rot symptoms have been observed (causal agent to be diagnosed). Potato harvest has started. Potato late blight risk in our area has accumulated 12 disease severity values (DSV). No new reports have been issued in Michigan or neighbor states in the past week.
Cucumber, squash and zucchini harvest continues. Powdery mildew continues to be observed in several cucurbits fields. Cucurbit downy mildew epidemic continues in Michigan and the United States. The weather in the following weeks is going to be highly conducive to this and other diseases. For cucurbit downy mildew control, see “Spray Recommendations for Downy Mildew.”
An adult squash vine borer was found in the Monroe County trap. Squash vine borer flight will be completed in 326 GDD (base 50 F). Scout your fields for frass, wilted vines, larvae point of entry and larvae inside the crown of wilted vines. For labeled insecticides and rates, consult the Michigan State University Extension E312 bulletin “2013 Insect, Disease and Nematode Control for Commercial Vegetables” and always read insecticide labels.
If you are going to be done harvesting some fields and are interested in trying some cover crops to improve soil health and weed control, visit Midwest Cover Crops Council Cover Crop Decision Tool and read the instructions for using the Vegetable Cover Crop Decision Tool.