May 23, 2008

Conditions in Nebraska's Panhandle range from abnormally dry to extreme drought, a concern for Nebraska's wheat crop. (Source: National Drought Monitor)

Paul Hay, Extension Educator in Gage County: Many fields of first cutting alfalfa hit the ground over the last few days. Corn planting is nearly complete, and soybean and milo planting are past the half-way point. Both ground rigs and aircraft are busy applying fungicide on wheat.

Dave Stenberg, Extension Educator in Dawson County: Corn planting is 99%+ complete and soybean planting is two-thirds finished. It took a month to plant corn, but only 10-12 days for emergence. There were a few reports of replanting early planted corn. Cool temperatures have delayed alfalfa growth about a week. On the plus side, cool temperatures — some below 32°F — slowed alfalfa weevil development. We don't expect an economic level of weevils this year. Pastures should really grow with the moisture we have received and now some warm days.

Michael Rethwisch, Extension Educator in Butler County: Alfalfa looks good and several fields have had a first cutting. Several uncut fields in Butler County were swept to document insect activity. No alfalfa weevil larvae or adults were collected as of May 21, but a few bean leaf beetles and tarnished plant bugs were noted. Insects present in highest numbers were pea aphids (including a few pink forms),ladybird beetles and parasitic wasps. Many corn and soybean growers completed planting this week: early planted corn fields emerged and were easily rowed. Some wet spots still need to be planted.

Wheat conditions vary by location, with lower parts of some fields having an off-green color and yellowing of lower leaves, likely due to lack of adequate oxygen in these field areas which affected nitrogen uptake. Upper parts of these fields were a much darker green. Diseases have been of concern but not generally noted due to recent dry conditions. Rain and wet conditions are favorable for stem and leaf rust, but we haven't had anypositive samples from Butler County yet. For the most part the crop is progressing nicely, with tillering and an occasional head encountered.

Drew J. Lyon, Dryland Cropping Systems Specialist, Panhandle REC: A lot of the winter wheat fields in the Panhandle are in need of rain. Several days of warm, windy weather have resulted in areas of blue-gray plants showing up in many fields. Wheat is growing rapidly and is approaching the boot stage, which is the start of maximum water use by wheat. Continued dry and warm conditions will begin to take their toll on the winter wheat crop in the Nebraska Panhandle. Drought symptoms are showing up first in areas with shallow and or coarse textured soils, areas where weeds were not controlled last summer, and where wheat was planted after a summer crop, i.e., not planted after summer fallow. High wheat prices last fall encouraged a lot of Panhandle wheat growers to seed some wheat into fields that had not been summer fallowed.

William Booker, UNL Extension Educator in Box Butte County: Wheat across the Panhandle last weekend was showing signs of dry weather and confirmed our fears regarding minimal subsoil moisture. Irrigated fields look good but dryland fields are now depending on rains to make the crop. The wheat is in the vegetative stage so lack of moisture may result in shorter wheat, especially in dryland fields. WIth moisture these fields can still produce a good crop, but showers have been spotty. Winds blowing all day and night up to 65 mph this week have caused some problems, including visibility problems across the Panhandle on Wednesday. Showers totaling 0.35 inch here in Alliance has stopped the soil wind erosion but the wind continues. Sugar beets, along with other emerging crops, suffered soil erosion caused by the wind.

Dewey Lienemann, Extension Educator in Webster County: Jenny Rees, Extension Educator in Clay County, and I surveyed fields in south central Nebraska last week. At that time we didn't find much disease in the wheat fields, even though conditions said it should be there. This week, however, we are finding early indications of something developing. Most of our wheat in this area is in late boot stage, or actually starting to head out. It seemed to develop from flag stage to heading literally overnight. This week both Jenny and I again examined fields across a broad area and found several fields with flag and other top leaves that were exhibiting "speckles" in various degrees of severity. These are relatively new occurrences. You don't see these leaf specks by just walking through the field, but rather by holding the leaves up to sunlight.

The extent ranges from many leaves to just a few leaves with potential infection and several degrees of infestation per leaf. At this point, we've taken samples but haven't confirmed the cause. I have not seen this before. My gut feeling is that it is the precursor of rust pustules or some other fungus attack. Growers should keep an eye on their fields and be prepared to react accordingly. Soon, the usual fungicides will be past their label limit for application. Producers who feel pressed to spray in case something might develop should consider another option.

Two new fungicides, Proline (prothioconazole) and Folicur (tebuconazole), can be used to suppress Fusarium head blight (FHB) and rust diseases on wheat and can be applied later in the growing season. Both of these products give you an opportunity to wait out the current weather. With a bigger window for decision-making, you can watch to see if these early signs on the flag leaves develop into a serious problem. If it pans out to be nothing, nothing is really lost; if speckles develop into rustpustules, you have an option left to protect your wheat. Of course, the goal is to protect your flag leaf which makes up approximately 75% of the effective leaf area that contributes to grain fill. For more information on Proline and Folicur, see previous CropWatch articles by Plant Pathologist Stephen Wegulo in the March 7 and May 16 issues.

Reports of other crops include: Most corn is in the ground and about half the beans are planted. First emergence of corn was May 4 in Webster County with beans first emerging May 20. We had some problems with crusting on several recently planted fields and the wheat needed a big drink, both of which should be helped with recent rain (up to 5 inches in areas of Webster County) Of course this copious rain may bring be a mixed blessing — it could mean some replanting and there is some erosion. Pastures are still slow coming but should burst now.