Field Updates: Corn and Soybeans Experiencing Heat and Moisture Stress - UNL CropWatch, Aug. 1

Field Updates: Corn and Soybeans Experiencing Heat and Moisture Stress - UNL CropWatch, Aug. 1

August 2011

Corn tasseling

Above:  Some of the corn shown here pollinated before the high temperatures while some has yet to become pollinated.  (Photos by Tom Dorn)

Below:  Corn in eastern Nebraska recovering from severe moisture stress and high temperatures.

Stressed corn field

Lowell Sandell, Extension Educator - Weed Science in Lincoln:  Yellow flash has been a common site in Nebraska soybean fields this summer. This Plant Management Network video by Extension Weeds Specialist Mark Bernards describes the process and environmental conditions leading to yellow flash. It also addresses the postemergence use of manganese (MN) in soybeans. (8/5/11)

Paul Hay, Extension Educator in Gage County:  Dryland corn in much of southeast Nebraska has been hurt and will be hurt more without rains in the next few days. A field near Clatonia may make 50-60 bu/ac with rain this week. The matching field made 140 bu/ac last year. I think we may be close to a 100 bu/ac average this year at this point versus a 130+ average last year. Soybeans are hanging in, but dropping lower leaves and aborting some smaller pods. Milo fields stalled at heading. Rains have been very streaky so lots of haves and have nots. (8/4/11)

Doug Anderson, Extension Educator in Keith, Arthur, and Perkins Counties:  Rainfed are in need of rain as we have missed out on the last few storms.  If we can get a couple inches soon, it looks pretty good for the crops.  Sporadic hail has caused some crop and yield loss.  Grasshoppers are causing some damage n crop acres, but pastures are still looking good.  Generally, things are starting to look dry.  It's still not critical, but a rain would be nice.  (8/4/11)

Karen DeBoer, Extension Educator in Cheyenne County:  Our dryland crops are looking stressed from the heat and lack of moisture, especially the dryland corn that I have seen. Wheat harvest is progressing in the area with reports of average to above average yields, good test weight, and low protein.  (8/1/11)

Jenny Rees, Extension Educator in Clay County:  Overall, things are hanging in there, particularly in dryland areas. We've had some major wind storms that have caused greensnap and damaged pivots and collapsed bins. Soybeans are in the R3 to R5 stages and bean leaf beetles and grasshoppers are visible. It seems like a lot of fungicide and insecticide went on soybeans this year.

Corn growth also varies a great deal and is moving along fast.  Planes have been flying fungicide for three weeks now even though gray leaf spot is still not a significant problem in most fields that haven't been sprayed yet. Related to pollination problems, I saw some blank kernels in nearly every field I visited today.  (See more in Projected Yields.)  Even though there is soil moisture in much of the area, pivots are running to cool off the canopy to avoid the corn shutting down early like it did last year.(8/1/11)

Jeff Bradshaw, Extension Entomologist at the Panhandle Research and Extension Center in Scottsbluff:  We're seeing a more normal population of cutworm moths that we saw last year. Moth flight peaked at over 1,000 a night in traps, but is declining now. Grasshoppers are moving into some crop areas (see CW story) and there is concern among growers getting an extra cutting of hay about what they could do. We're adivising that they probably don't have to treat that second growth, but their neighbors would thank them if they did.  Potato psyllids are present in the Imperial and Bridgeport areas and potato acres are being treated. Last year we didn't see psyllids at Scottsbluff until mid-April.(8/1/11)

Robert Wright, Extension Entomologist in Lincoln:  We saw a good moth flight of western bean cutworms at the South Central Ag Lab at Clay Center. A wide variance in planting date might account for the hotspots in some fields. Moths prefer pretassel corn if they have a choice and later planted fields appear to be hit harder. (8/1/11)

Keith Glewen, Extension Educator in Saunders County:  Bean leaf beetle populations seem high this year and should be monitored.  The skies in this area have been full of planes making applications on row crops.  This may be a record year for detasseling as some crews may need to work as late as Aug. 20 due to the late planting season and slow start to the crop. (8/1/11)

Mark Hinze, Extension Educator in Hall County:  We had a lot of seed corn acres destroyed due to greensnap and growers are considering management options for these fields.  (See CW story related to cover crop use in these fields.) Downed plants in some of the damaged fields are goosenecking up and producing a tassel.  We're also seeing a lot of "flashing" in fields, a lot of European corn borer moths, and some Asian soybean aphids. Pivots are running. Growers doing irrigation scheduling are starting to watch their data loggers and deciding to cut back their irrigation.  (8/1/11)

Wayne Ohnesorg, Extension Educator in Madison County:  We're in need of some rain here, particularly in the northern part of the county where it's very dry.  Grass hay has been put up and we're starting to consistently see soybean aphids in fields. With temperatures dropping to the 80s, we could see aphid pressure building quickly.  (8/1/11)

John Wilson, Extension Educator in Burt County:  Soybean aphids are few and far between here.  The water in the flood acres along the Missouri River is starting to go down.  When all the water's gone, we're going to find fields that look different than they did early last spring.  One of our growers toured his field by boat and was using a depth finder to monitor water depth.  At one point in 8 foot water he found a new trench 30-35 feet deep in the middle of the field.  (8/1/11)

Tom Dorn, Extension Educator, Lancaster County: The extreme heat plaguing the Midwest the last couple of weeks has taken a toll on crops. Corn plants in rainfed fields in Lancaster County were generally able to produce silks; however, as I surveyed area crops on July 27, a small but significant portion of the plants in some fields had silks that did not appear to be successfully pollinated. My guess is that some of the pollen became desiccated before it reached the silks due to the high air temperatures. A follow-up trip to a couple of fields on July 29 found less leaf rolling and some new pollen being shed. The cooler temperature appeared to be aiding pollination.  Signs of moisture stress were evident in most fields during the daylight hours. Leaves were wilting and rolling and lower leaves were beginning to experience tissue death (firing) due to lack of moisture.(8/1/11)

If this weather pattern continues, we may need to consider alternative uses for drought stressed corn. One resource I would call to your attention is The Use and Pricing of Drought-Stressed Corn, UNL NebGuide G1865.  (7/29/11)

Paul Hay, Extension Educator, Gage County:  Rains have been spotty, but the driest area of southeast Nebraska along the Kansas border was helped by a couple rains last week.  Crops look good, as humidity has been holding down water demand.  We are in need of general rains of 1-2 inches across the area in the next few days to avoid losses in corn.  (7/30/11)

Gary Zoubek, Extension Educator in York County: The fields I've been out in are irrigated (not much) but have adequate soil moisture and I'm not seeing pollination problems in the corn or problems of the beans not setting pods. I've talked to a couple of crop scouts who have not seen a lot either. The humidity has helped and the winds have not been hot and dry.   (7/30/11)