Northeast Michigan field crops regional report – July 11, 2013
The first signs of moisture stress became apparent in northeast Michigan last week.
Weather and rainfall
Precisely 0.28 inches of rain fell Monday, July 8, ending a nine-day streak of hot, dry weather in northeast Michigan. Soil moisture decreased enough during that period to cause drought stress in crops growing on excessively drained, coarse-textured soils. Plants look better now, but only temporarily. A high pressure system of Canadian origin will move into our area this weekend (July 13-14), severely limiting any chances for additional precipitation over the next several days. The 6-10 and 8-14 day outlooks from NOAA indicate a slight chance for above normal precipitation in coming weeks, but this may not pan out according the Michigan State University’s agricultural meteorologist Jeff Andresen.
Growing degree days (GDD)
Above normal high temperatures in the mid-90s added to our GDD accumulations last week. GDD accumulations since March 1 total 2,323.5 base 32 degrees Fahrenheit; 1,433.5 base 41 F; and 899.1 base 50. Storms on Monday (July 8) brought some relief this week, with lower humidity and daytime highs in the mid-70s. Another warming trend will kickoff early next week. The 6-10 day outlook from NOAA indicates that our region will likely experience above normal temperatures in coming weeks.
Most winter wheat in our region is in the early to mid-dough stage of grain fill. Some fields are beginning to lighten in color, but premature ripening due to environmental or management related stresses may be a factor. Fungal leaf diseases mounted resurgence over the last few weeks. Powdery mildew has spread to newer leaves in stands that showed signs of infection earlier in the season. Stripe rust pustules were observed for the first time this year the week of July 4. Fusarium head blight (scab) pressure continues to be very low in fields across Presque Isle County. However, other parts of the state are reporting late season scab infections, and the area from Crawford County southeast to Iosco County is now facing a “medium” blight risk according to the Fusarium Head Blight Prediction Center.
In alfalfa, nearly all of first cutting hay has been put into storage across northeast Michigan. With harvest delayed by weather in some areas, reported yields are quite high, but quality likely suffered. Harvest has eased the market slightly, but prices remain in the range of $130 to $200 per ton for alfalfa grass hay. Forage producers that wait until after first cutting to topdress fertilizer are making those applications.
Alfalfa regrowth is 4 to 10 inches tall in fields that were cut early. Leafhopper pressure has increased rapidly over the last few weeks. Growers hoping to apply insecticides for leafhopper control should plan to treat when the new growth is approximately 6 inches tall. A few tarnished plant bugs have been spotted, but no significant damage has been reported. Uncut bromegrass is flowering.
Corn in our region ranges in development from the five-leaf to nine-leaf stage (V5-V9). Warmer temperatures have greatly improved the crop’s general condition and growth. Sidedress nitrogen and early herbicide applications are largely complete. A few applications resulted in crop injury. Stinkbugs have been spotted in the field, but no significant injury was observed. Deer feeding is evident in most fields, ranging from slight leaf damage to complete destruction of individual plants.
Soybeans in the northeast have three to five fully emerged trifoliate leaves. Weed pressure is building rapidly in many fields, with 6-inch lambsquarter and pigweed competing aggressively with the young crop. Late-planted beans are receiving an initial herbicide application, while some earlier plantings are already in need of a second application.
The numerous small, brown lesions indicative of Septoria brown spot are becoming evident on the lower leaves of some plants. Soybean aphid numbers are also increasing. The technical treatment threshold for soybean aphids is 250 individuals per plant on 80 percent of the plants in a field. However, economic damage does not occur until 400 to 600 aphids colonize a plant, and natural enemies of soybean aphids, like lady beetles, often respond quickly to help growers control outbreaks. As a result, Michigan State University Extension recommends delaying insecticide applications slightly beyond the 250 per plant threshold to determine if natural enemies are capable of controlling the aphid population. Insecticide applications have the potential to make aphid infestations worse by eliminating natural enemies and incompletely controlling the pest, which quickly recovers.
Early planted potatoes are flowering and hilling is well underway. Some irrigation equipment was running during the latter part of last week, but the rain we received on Monday, July 8, has improved soil moisture conditions. Leafhoppers have moved into potato fields now that hay has been cut. Colorado potato beetle pressure is also increasing, triggering foliar insecticide applications in some areas.
Dry beans in our region have three to five emerged trifoliate leaves and appear to be in good condition. The first cultivation pass has been made in most fields, and weed control remains excellent overall. No western bean cutworm moths have been trapped at our monitoring sites. However, moths have been observed in the southern part of the state and we expect them to show up in our area soon.
Other Michigan State University Extension field crop regional reports from this week: