Northeast Michigan field crop regional report – July 10, 2014

Cool temperatures moderate crop development across the region.

Potatoes in northeastern Michigan are beginning to form daughter tubers. Photo credit:  James DeDecker, MSU Extension

Potatoes in northeastern Michigan are beginning to form daughter tubers. Photo credit: James DeDecker, MSU Extension

Weather and rainfall

There was 0.66 inches of rain measured at the Hawks Enviro-weather station over the first ten days of July. This total is 0.20 inches above the five-year average for this period. Precipitation has actually been quite consistent for the last month or so, with light to moderate rain events occurring every few days. Our next significant chance for rain will come Saturday, July 12, with showers possible through Wednesday morning. The 6-10 and 8-14 day outlooks from NOAA indicate a good chance for below normal precipitation in coming weeks, which will likely shift soil moisture conditions toward a slight mid-summer drought.

Growing degree days (GDD)

High temperatures over the last week have ranged widely from 69 degrees Fahrenheit to 86 F, with lows between 45 and 61 F. GDD accumulations since March 1 total 2205.3 base 32 F, 1401.8 base 41, and 785.6 base 50. Cool nighttime temperatures have once again set our region back a week or so behind the 30-year average, and are limiting the development of certain crops like corn. Conditions are not expected to improve, in terms of temperature, over the next week. Daytime highs will likely not reach beyond the low to mid 70s. The 6-10 and 8-14 day outlooks from NOAA indicate that our region will also very likely experience below normal temperatures in coming weeks.

Commodity reports

Winter wheat in our region remains mostly green, but a few stands are beginning to lighten in color. Grain maturity ranges from early milk to late milk stage (Feekes 11.1). Fungal leaf disease pressure has increased rather dramatically over the last few weeks. Fields not treated with a fungicide are showing progressive symptoms of stagonospora blotch and powdery mildew, in some cases impacting flag leaves and the maturing heads. However, scab infected heads are hard to come by in most fields, and the risk of mycotoxins in harvested grain should be quite low this year. Bleached-looking heads are evident in many areas, but are in most cases associated with tillers terminated by stem maggots rather than scab infection. These heads lack any maturing grain and tend to break from the plant mid-stem where feeding has occurred.

Growers who did not apply an herbicide to wheat earlier in the season may be considering preharvest options to control weeds growing through the canopy. Michigan State University Extension’s wheat educator Martin Nagelkirk reminds producers the herbicides labeled for preharvest applications include Glyphosate, 2,4-D, Aim and Clarity. He notes that, “very few have experience using preharvest applications. Growers should use caution. It is critical that the grain be mature or about 30 percent moisture. At 30 percent moisture the tissue has lost all or nearly all its green color and the kernel is difficult to split with a fingernail. Wheat grown for seed should not be sprayed.”

Growers are encouraged to refer to the MSU Weed Control Guide (see page 108 under Small Grains section), as well as note and follow harvest interval restrictions. Early-planted oats and barley are now mostly headed.

Most first-cutting alfalfa hay has been put into storage across northeast Michigan. Regrowth on cut fields is four to twelve inches tall. Some grass forage remains standing or cut in the field, as harvest has been interrupted by scattered rain events over the last two weeks. Statewide, first-cutting forage yields and quality have been variable, and high-quality alfalfa hay prices will likely increase in response. Alfalfa weevil pressure remains low in our area. Potato leafhopper and tarnished plant bug numbers are increasing in sweep net surveys, but feeding damage is quite limited at this point. Forage producers who wait until after first cutting to top-dress fertilizer are making those applications. Uncut brome grass and timothy are flowering.

Corn in our region ranges in development from the four-leaf to eight-leaf stage (V4-V8). It is impressive how far along the crop is despite later planting. Still, relatively cool nighttime temperatures have growers concerned that corn may fall short of maturing before first frost. Side-dress nitrogen and herbicide applications are largely complete. A few nitrogen applications resulted in minor crop injury. V8 is the cut-off point for glyphosate applications in corn, and some growers are rushing to get herbicide on in time. European corn borer and earworm numbers remain low. Stinkbugs have been spotted in the field, but no significant injury was observed.

Soybeans in northeastern Michigan have three to five fully emerged trifoliate leaves. Weed pressure is building rapidly in many fields, with six inch lambsquarter and pigweed competing aggressively with the young crop. Late-planted beans are receiving an initial herbicide application, while some earlier plantings are 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 aphids have not been an issue thus far. Now is an excellent time for growers to check nodulation on soybeans. Inoculation failure is often an issue on new soybean ground, but can occur elsewhere. Plants should be dug rather than pulled to judge nodulation, and a minimum of seven pink-centered nodules two millimeters or greater in diameter is considered acceptable. Fields with poor nodulation should receive 60-70 pounds of actual nitrogen as ammonium nitrate, stabilized urea or twenty-eight percent applied using streamer bars or drop nozzles.

Early planted potatoes are beginning to develop buds, and in some cases flower. Tuber initiation is also underway, with daughter tubers ¼ to 1 ½ inches in diameter. Hilling and sidedress fertilizer application has continued in the last week. Colorado potato beetle larvae are in their second instar on susceptible plants and nightshade weeds. Growers may consider foliar insecticide applications in certain areas. Leaf roll and mosaic virus infected plants are becoming more obvious, particularly in fields planted with saved seed. Rhizoctonia stem canker can be observed on dug roots and stolons, but pressure appears limited overall.

Dry beans in our region have two to four trifoliate leaves and condition of the crop is improving with time. The first cultivation pass has been made in most fields, and weed control appears to be good overall. Symptoms of root rot are showing in isolated areas, with yellowing leaves and roots declining rapidly. No Western bean cutworm moths have been trapped at our monitoring sites in the northeast or downstate, and flight of this pest is expected to occur later than usual.

Other Michigan State University Extension field crops regional reports from this week:

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