Last week continued the stretch of dry weather with little to no precipitation falling since May 8th. It was sort of a roller coaster ride in the temperature department with highs near 80F most days, however, highs struggled to reach the mid 60’s during the midweek time frame thanks to a backdoor cold front. The Omega/Rex blocking weather pattern has been persistent in keeping Wisconsin and the Great Lakes region warm and dry while the Rockies/Great Plains and the Carolinas are receiving rainfall. This stubbornly stuck weather pattern appears to continue for the foreseeable future.
The harvest of 1st crop alfalfa began late last week and will likely pick up steam after the Memorial Day holiday. Yields appear to be good to excellent on some fields, however, there are some fields that are struggling to produce. There are some fields that have areas of winter injury. The alfalfa greened up slowly in areas of alfalfa fields this spring. Alfalfa plants were dug up with a shovel and the roots were examined. The regrowth on the alfalfa was asymmetrical meaning that growth is only occurring on one side of the plant. Stem count in these troubled areas is half of what is need for a productive stand. Roots were split opened and little to no discoloration was noted except maybe at the top of the crown due to equipment traffic damage. Soil samples were pulled in the bad and the good areas to see if there was a fertility issue that may have predisposed these alfalfa plants to winter injury. These alfalfa plants were taken from well drained, productive soil south of Malone on the hills.
Sweep nets have caught a few alfalfa weevil and aphids in 1st crop alfalfa, but so far their populations remain relatively low.
Corn and soybean planting is nearly completed in the southern Lake Winnebago region. Canning crops such as peas and snap beans are being planted as well.
Preemerge herbicide applications are being applied to both corn and soybeans with the hopes that a soaking rain of 0.5 inch to 0.75 inch comes soon to get the herbicide into the soil solution where it can kill germinating weed seeds.
Winter wheat currently is at the flag leaf stage of development. This corresponds to Feekes 8 to 9. Wheat will likely reach the boot stage this week (Feekes 10). Fungicide applications targeted at protecting the wheat from head scab and fungal diseases of the upper leaf canopy will commence in the next two weeks. Products such as Miravis Ace and Prosaro are products of choice.
Powdery mildew of wheat was found in a single field of wheat in the Malone area. The disease was found in a thick stand of wheat. The wheat was planted in early September on a terminated alfalfa field. This field had received plenty of nitrogen credits from manure and alfalfa. Powdery mildew development is favored by cool to mild temperatures, high relative humidity, and high nitrogen levels. The greatest yield loss caused by this fungal disease occurs when it reaches the flag leaf and the leaf below the flag leaf. These upper two leaves account for nearly 75% of total wheat yield. This disease can interfere with photosynthetic activity in the upper two leaves which can cause a severe reduction in yield. (See attachment)
Most of our summer annual weed species that we deal with in our crops have emerged. This week our later emerging problem weeds such as crabgrass, pigweed, and waterhemp have been discovered in area fields. Yellow nutsedge, a perennial weed of wet soil, has been spotted as well.
Little to no rain fell the entire week which allowed soil conditions to dry. Soil in fields with cover crops and heavy crop residue still trended to be on the wetter side. Soil temperatures early in the morning at 6:00 AM hovered around the lower 50s most days...
