Northeast Michigan field crops regional report – Aug. 8, 2013

Frequent rainfall and cool temperatures have enhanced pollination, but wheat is sprouting in the field.

Weather and rainfall

Approximately 1.82 inches of rain has fallen in almost daily precipitation events at the Hawks Enviro-weather station since Thursday, July 25. This extra moisture paired with cool temperatures have made the last two weeks ideal for crop pollination in northeast Michigan. However, the rain has also complicated wheat and forage harvest operations. The only significant chance for precipitation in the next 10 days will come Friday, Aug. 9. The 6-10 day outlook from NOAA indicates a significant chance for below normal precipitation. However, the 8-14 day outlook shows the opposite, a good chance for above normal precipitation.

Growing degree days (GDD)

Recent cool temperatures have slowed the accumulation of growing degree days in northeast Michigan. Parts of our region are now three calendar days to one week behind the 30-year average for GDD accumulation. This may compromise the maturation of some crops, particularly longer season corn varieties. GDD accumulations since March 1 total 3,253.9 base 32 degrees Fahrenheit, 2,114.5 base 41 and 1,350.9 base 50. Unseasonably cool temperatures will likely persist for quite some time. The 6-10 and 8-14 day outlooks from NOAA suggest that our region will very likely continue to experience below normal temperatures in coming weeks.

Commodity reports

About three-quarters of the winter wheat in our region has been harvested. Reported yields range from 20 to 60 bushels per acre, 55 being average. Test weights have been good, but much of the grain sampled has an unacceptably low “falling number,” which indicates pre-harvest sprouting. Sprouting can occur when unharvested wheat dries to less than 20 percent moisture and is then remoistened by rain or high atmospheric humidity.

Frequent, sporadic precipitation events over the last three weeks paired with cool temperatures have delayed harvest and rewet the grain several times. When this occurs, the kernels break dormancy and begin to grow before they even separate from the head. As the berries sprout, enzyme activity alters physical properties of their stored starch in ways that reduce milling and baking quality. The “falling number” is a measure of how long it takes a metal plunger to fall through a test tube filled with a flour-water slurry. The viscosity of the slurry, and thus speed of the plunger’s fall, is correlated with mixing strength, loaf volume and shelf life of resulting baked goods. Higher numbers indicate higher quality.

The majority of sprouted wheat is used as livestock feed. Though not wasted, the feed market pays as little as 50 percent of the milling market price. Still, growers are encouraged to shop around to receive the best possible price. Wheat producers have few other options when their crop contains sprouted grain. If significant sprouting is detected before a field is harvested, growers are encouraged to contact their crop insurance agent to determine the potential value of a total loss claim versus the market price for feed grade wheat.

After harvest, sprouted grain can be dried and stored to wait for improved market conditions. Depending on how many kernels are sprouted and how far along they are in the process, the damaged grain can also be saved for seed. If this is done, a germination test is recommended and the sprouted grain should ideally be used for earlier plantings.

Third cutting alfalfa in northeast Michigan is 3 to 15 inches tall with neutral detergent fiber (NDF) concentrations near 27 percent. Many forage producers have been forced to delay second cutting due to our recent wet weather. As a result, second cutting alfalfa still standing in the field is 18 to 38 inches tall and blooming. NDF concentrations in those stands are higher than ideal at 47 percent. Fields mowed in the last two weeks received rain before the hay could properly cure and dry for baling. Both delayed harvest and compromised preservation will reduce the quality of late second cutting hay in our region.

New stands are filling out nicely. Oat nurse crops are in the dough stages of development and will be harvested soon for grain or livestock feed.

Corn in the northeast ranges in development from the nine leaf to blister stage (V9-R2). Producers are concerned that unusually cool temperatures have slowed development of the crop. Bountiful moisture and a lack of heat stress contributed to excellent pollination in most fields. However, later maturing hybrids may not have enough growing degrees days left in the season to ripen all of the grain that has been initiated.

A few growers have reported significant fall armyworm pressure. Most transgenic Bt hybrids will provide some protection against armyworm feeding. A biotype of fall armyworm resistant to the Cry 1F Bt toxin was identified in Puerto Rico, but incidence of resistance are not widespread in the continental United States. Insecticide applications are usually not warranted unless the infestation is severe – 100 percent of the plants infested. Even then, ground application to tall plants can be unpractical.

Many soybeans in our region are continuing to flower, while the earliest maturing varieties have 0.1875-inch pods at the upper most nodes (R2-R3). Crop growth and canopy fill have progressed rapidly over the last couple of weeks, despite cool temperatures. A few fields are showing marginal chlorosis of older leaves and stunting, symptoms of potassium deficiency.

Significant white mold pressure has been reported in Tuscola County. White mold has not been reported in our area, but recent weather conditions certainly favor the development of fungal diseases. This has encouraged some growers to apply foliar fungicides to their crop. Fungicide applications should ideally be made during flowering and prior to disease development. Later applications are much less effective.

Potatoes are progressing through the tuber bulking stage of growth. During this stage water, nutrients and carbohydrates are deposited in tuber cells, and yield is determined. Tubers can add six to 10-hundred weight per acre each day during this period. However, any pest pressure or environmental stress can slow tuber growth and ultimately reduce yield.

Insecticide applications are being made to control Colorado potato beetles and leafhoppers. A second case of late blight was confirmed in St. Joseph County on Aug. 5. Recent weather conditions could encourage development of the disease in our region. MSU’s potato pathologist Willie Kirk suggests that growers maintain a seven-day fungicide spray schedule using a labeled translaminar fungicide to protect their crop from late blight and other fungal diseases. Northeast Michigan’s Michigan State University and Michigan Potato Industry Commission summer potato meeting is scheduled for Aug. 27 at 2 p.m. at the Route 65 Diner in Posen, Mich.

Dry beans in our region are taking advantage of the cool, wet weather, continuing to flower and set additional pods. Early pods at the lowest nodes are up to 7 inches long. However, persistent moisture has producers concerned about diseases, including white mold and halo blight. Several growers have sprayed insecticides to control leafhoppers. The threshold for potato leafhoppers in dry beans is one adult per trifoliate leaf.

Western bean cutworm flight has also picked up. Our traps have caught two to 42 moths over the last week. The official economic threshold in Michigan is 150 moths per trap, but growers have observed unacceptable crop damage at numbers as low as 30 moths per trap. While Michigan State University Extension does not recommend insecticide applications to dry beans for western bean cutworm control at current flight numbers, growers are encouraged to scout their crop for feeding damage to blossoms and pods and assess pressure on an individual field basis.

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

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