Corn and Soybean Planting Periods: The flowers/trees have been beautiful in the midst of a cool, dry, windy spring. I’ve been thinking about planting windows a lot. Appreciate all who have communicated thoughts on planting. From these conversations, I feel there’s been a shift in thinking, at least for this part of the state, with more paying attention to cold snap windows. Also been a shift to planting soybeans earlier or at the same time as corn. But to show whether that’s true or not, can you please help me with a quick one question visual survey on planting: https://app.sli.do/event/eV5gr4ioSZiSQKabEwRheB? It’s not letting me embed it, so you’ll have to click the link.

From what I’m hearing, planting progress ranges. Some are completely done, some are done with one crop or the other; many will finish this week. Others (mostly non-irrigated) are just starting this week. Some are concerned about May planting and yield loss. The rest of this info. mostly pertains to corn with encouragement that data has shown corn yields not to drop off till after mid-May planting dates. The article links provide the hard data.

Dr. Jim Specht, Professor Emeritus of UNL Agronomy and Horticulture, put together an article we will hopefully release in CropWatch this week. He was using NASS Nebraska Corn and Soybean 50% planting progress in comparison with NASS reported yields. Two key findings based on 43 years of data are:

• Delays in the Nebraska corn 50% progress date that occur within the May 2 – 12 planting period do not have an appreciable impact on resultant corn yield.
• The Nebraska soybean 50% progress date has advanced by eight days from a 43-year mean of May 22 to an expected May 14 date for the 2023 season.

Dr. Roger Elmore, also an Emeritus Professor of UNL Agronomy and Horticulture, had shared a similar sentiment in a 2019 CropWatch article where he shared about planting windows for corn using UNL research and NASS data. He shared, “A planting window exists within which (corn) yields do not vary tremendously. That window starts to close after mid-May. Many factors in addition to planting date influence final yields. There is always a chance that late-planted corn may out-yield early-planted corn.” Dr. Bob Nielsen, Emeritus professor at Purdue University shares similar key points for corn in an article, “Early planting favors higher yields, but does not guarantee higher (corn) yields. Statewide averages for planting progress and yield are not strongly related. Planting date is but one of many yield influencing factors.”

Alfalfa Weevils: I haven’t checked alfalfa fields yet, but had been watching comments down in Kansas. Alfalfa weevil larvae had hatched in southern Nebraska and also at the research station near Mead. In spite of planting, be sure to monitor alfalfa fields.

Dr. Bob Wright, Extension entomologist, and colleagues share the following in a recent CropWatch article. “The larvae of alfalfa weevils feed on first cutting alfalfa as larvae, and adults (and sometimes larvae) feed on the regrowth after the first cutting. In the Panhandle and in the northern tier of counties, there may be two flushes of weevil larvae this spring, leading to regrowth damage after the first cutting. Observations indicate the cause may be due to significant survival of both adult and larval weevils.”

It basically takes 1-2 alfalfa weevil larvae per stem to reach the economic threshold with today’s alfalfa prices. Take 10 stems from an area of the field, cut at ground level and hit them on the inside of a bucket. Count the number of weevil larvae present (also make sure to unfurl the bud leaves as some stay trapped in there). Depending on how close you are to harvest, one can choose to not treat and just harvest the alfalfa field while watching the green up for potential need to treat then, or treat prior to taking first cutting if harvest is still a ways off and economic thresholds are met. Insecticides for alfalfa weevil control include those that are pyrethroids (active ingredient ends in “thrin”) and products containing indoxacarb (e.g., Steward).