Central Michigan vegetable regional report – July 16, 2014
Weekend rain kept many soils very wet this week in the central Michigan region.
Rain showers producing 1-1.5 inches of additional rainfall kept many soils quite wet this week in the central Michigan region and kept many field activities on hold until soils can drain. Areas of flooding and standing water are not uncommon, especially on poorly drained soils.
Air temperatures have been below normal in early July. At Entrican, Michigan temperatures have ranged from the low to mid-70s F down to 66.8 degrees Fahrenheit as the observed high yesterday, July 15. Nighttime lows are in the upper 40s to mid-50s.
Potato growth stages are variable. Cultivation and hilling operations have been delayed due to the excessive soil moisture in many areas. Colorado potato beetle adults, egg masses and larvae continue to be found on volunteer potatoes and potatoes not treated with insecticides. Potato leafhoppers are present in low numbers as both nymphs and adults.
Crop scouts have found late blight in Montcalm County in a commercial potato field. It is the US-23 genotype. The high humidity, rain and warm temperatures have been favorable for disease development. Michigan State University Extension advises growers to continue applying protective fungicides to emerged potatoes. This has been challenging due to recent windy conditions and wet fields. If areas of fields are inaccessible and not sprayed, be sure to note those areas and scout them frequently for disease development. For more information, see “Late blight found in potatoes in Michigan’s Montcalm County.”
Tomato growers should also be applying protective fungicides to prevent late blight as US-23 is also highly infective of tomatoes.
Dry edible beans and snap beans are showing symptoms of stress due to saturated soils. Root rots are developing in many of these stressed fields.
Pickling cucumber fungicide applications to protect against downy mildew should continue as downy mildew has been confirmed in Gratiot County. While ground application is preferred, aerial application should be considered where soils are too wet to access with ground rigs.