Northeast Michigan field crop regional report – July 24, 2014
Several crops are entering the reproductive stages of development, which are critical for yield.
Weather and rainfall
The last two weeks brought both warm weather and needed precipitation to northeast Michigan. A total of 3.37 inches of rain has fallen at the Michigan State University Hawks Enviro-weather station since July 1, 1.77 inches above the five-year average for this period. Rain will likely return this Saturday, July 26, with precipitation likely through the following seven days. The 6-10 and 8-14 day outlooks from NOAA suggest a good chance for near to slightly above normal precipitation in coming weeks.
Growing degree days (GDD)
Five days of high temperatures in the 80s and 90s have pushed along crop development in our region. GDD accumulations since March 1 total 2,669.4 base 32 degrees Fahrenheit, 1,739.9 base 41, and 999.4 base 50. Despite recent advances in GDD accumulation, daytime highs will hold in the mid-70s for the next seven days. The 6-10 and 8-14 day outlooks from NOAA indicate that our region will very likely experience below normal temperatures in coming weeks. More cool weather will put us further behind our average growing season, and could compromise the development of corn in particular.
Maturation of winter wheat in northeast Michigan has been accelerated by recent warm weather. Stands are lightening in color and grain is in the dough stage of ripening. The grain fill period was extended this year by low stress conditions, which should maximize yields in early planted, intensively managed stands. Scab pressure has also been low, setting the stage for high grain quality. Some fields are beginning to show signs of sooty head molds, but these fungi are normally inconsequential. Harvest will likely begin within the next 10 days. However, rain in the forecast could delay harvest and potentially promote pre-harvest sprouting for the second year in a row.
Second cutting alfalfa is 4 to 22 inches tall in fields that were cut early. Leafhopper pressure has increased over the last few weeks, but most of their feeding seems to be concentrated in potato and dry bean fields. Growers hoping to apply insecticides for leafhopper control should plan to treat when the new growth is approximately 6 inches tall. White sweet clover is blooming in pastures and ditches. Livestock producers are reminded that while sweet clover can be used as forage, it is best to allow livestock to graze the plants rather than trying to preserve sweet clover as stored forage. Sweet clover contains coumarin, which can cause hemorrhaging in livestock when converted to dicoumarol by common storage fungi.
Corn in our region ranges in development from the seven-leaf to tassel stage (V7-VT), with the earliest planted fields just beginning to shed pollen. Once the tassel is fully exposed, silk emergence usually begins in two to three days. Some growers are considering foliar fungicide applications to protect corn from diseases like gray leaf spot and northern corn leaf blight. Several factors, including hybrid susceptibility, field disease history, crop rotation, plant date and irrigation frequency, should be considered when making the decision to apply fungicides. Susceptible hybrids that were planted late in irrigated fields with a history of fungal disease may benefit from a fungicide application. Growers will likely begin planning for a late maturing crop. Corn that has not reached the tasseling stage by weeks end is most at risk from an early frost.
Soybeans in the northeast have four to eight fully emerged trifoliate leaves and early planted stands are beginning to flower. Weed escapes, particularly lambsquarter and ragweed, are becoming a concern. Growers are reminded that beginning flower (R1) is the ideal time for foliar fungicide applications, and full flower (R2) is the cutoff point for glyphosate applications in soybeans. However, preharvest weed control options are available. Soybean aphid pressure remains low, but deer feeding continues to be a major issue in some field areas.
Potato hilling is largely complete. The crop in our region appears to be developing nicely through the flowering period. However, potato late blight has been detected in Michigan for the second year in a row. Plants from a Montcalm County farm tested positive for the US-23 genotype on July 16. According to Michigan State University Extension specialist Willie Kirk, the pathogen favors wet weather with moderate temperatures of 60 to 80 F, high humidity and frequent rainfall. While no cases of late blight have been reported in our region, most of the state remains at moderate risk for development of this disease.
Northeast Michigan’s MSU and Michigan Potato Industry Commission Potato Field Day is scheduled for Aug. 26 at 2 p.m.
Dry beans in our region have three to five trifoliate leaves and are just beginning to flower (R1). Mexican bean beetle and Japanese beetle damage has been observed in some fields, but appears to be mostly insignificant. A few growers are applying foliar fertilizers to correct symptoms of zinc and iron deficiency. No western bean cutworm moths have been tapped at our monitoring stations in the northeas