Southwest Michigan vegetable regional report – July 29, 2015
Summer has finally arrived in southwest Michigan.
After an up and down, start and stop beginning, summer has finally made it to southwest Michigan. Temperatures for the week ranged from 81 to 91 degrees Fahrenheit for highs and 56 to 68 F for lows. There was no rain for the period. We are near 1,610 base 50 growing degree days (GDD) compared to 1,490 for 2014.
Higher temperatures could affect fruit set on many plants. Tomatoes do not do well when day temperatures are in the 90s and night temperatures in the 70s. Honey bee activity also decreases as temperatures rise since more workers are needed to cool the hive. Flowers also do not stay open as long. Under high temperatures, spray activity should be restricted to the evening or early morning if possible. Spraying at temperatures above 85 F can cause plant injury. Spraying during periods of high bee activity can cause damage to bees and reduce fruit set.
Michigan State University Extension reports that downy mildew can be found in many cucumber fields. Vine crop producers need to step up their protection program by using the most effective materials and shortening spray intervals. Susceptible fields should be removed as soon as harvest is finished.
Cool, wet conditions followed by warmer temperatures, limited rainfall and increased fruit load has led to increased expression of root problems such as Verticillium in eggplant and Phytophthora and Fusarium in vine crops.
Fresh market tomato, eggplant and cantaloupe harvest has begun while volumes of other crops continue.
Watermelon and pumpkins continue to bloom and are setting fruit nicely.
Insect activity continues to be lower than usual. This has also resulted in a lower incidence of virus symptoms in vine crops.