Extension Crop Reports & Crop Disease Notes (July 10-13)
Troy Ingram, Extension Educator reporting for Greeley, Howard, Sherman, and Valley counties: Corn is at V12 to VT growth stage with little to no disease and insect pressure (some bacterial leaf streak and gray leaf spot). Soybean is at R2 to full bloom with little disease or insect pressure. The second cutting of hay is underway. We had really good moisture all spring, but now pivots are starting to run in sandier areas. In Custer County corn is at VT. In the southern part of the county they’re finding western bean cutworm and some rootworm beetles. Beans are looking good throughout the area. There is some iron chlorosis in soybeans in areas where we don't normally see it. (July 10, 2018)
Nathan Mueller, Extension Educator in Dodge County: Corn is at VT to R1. Soybean is at full bloom to R3. Growers are taking their second cutting of alfalfa. Wheat harvest started July 4 with yields of 65-80 bu/ac. (Our wheat acres are limited though.) Most areas saw 10 inches of rain in June and soil moisture was good going into July. We did get some green snap from storms passing through about two weeks ago. (July 10, 2018)
Megan Taylor, Extension Educator reporting for Platte, Boone, and Nance counties: Corn is at V9-R2. There’s some Goss’s wilt, a little southern corn leaf blight, bacterial leaf streak, and gray leaf spot. We received a significant amount of rain two to three weeks ago and some areas are still ponded over. With the storm we also had some pretty bad green snap in some areas. Japanese beetles are in corn, cutting silks. Soybeans are at R2. We’re seeing some bacterial blight and sudden death syndrome in beans. The second cutting of alfalfa is underway with an earlier cutting encouraged due to heavy alfalfa weevil presence. (July 10, 2018)
Todd Whitney, Extension Educator in Phelps County: Tasseling started a week or two ago and applications to control western bean cutworm started two days ago. Our biggest issue has been hail damage from the June 30 storm. We'll be hosting a meeting to look at post-hail crop management options July 17 in Holdrege. Wheat harvest is moving along and we’re about two-thirds done. Yields are not as good as the last two years, but likely near the state’s average. Test weights started good, but have dropped. (July 10, 2018)
Robert Tigner, Agricultural Economics Cropping Systems Extension Educator at the West Central REC: Growers are taking their second cutting of hay. Wheat harvest is underway and about two-thirds done. Corn is at R1. The chlorosis in soybeans here tends to be on side hills. (July 10, 2018)
Sarah Sivits, Extension Educator in Dawson County: Corn is just starting to tassel and pushing silks. We found some rootworm beetle adults in fields and grasshoppers in borders in western Buffalo and eastern Dawson counties. Bacterial leaf streak was found in Dawson, Buffalo, and Hall counties, and there was some common but no southern rust. We did have some storm damage in northern Dawson County from wind and flooding. Seed corn is a little behind and being rogued. Western bean cutworm is just starting to show up in western areas. Soybeans are at a range of stages, up to full flowering. A lot of soybeans are cupping and dicamba explore is suspected. Some Japanese beetles are causing defoliation in soybean, but will likely be moving to corn tassels now. The second cutting of alfalfa is underway and wheat harvest is rolling along. We’re just starting to see sorghum heads developing. (July 10, 2018)
Steve Melvin, Extension Educator in Hamilton County: Wheat harvest has been done for a week or two in Nuckolls County where yields were down (30 bu/ac) due to dry weather. Detasseling crews are just going out in seed corn. Some growers are going to see reduced yield due to volunteer. (July 10, 2018)
Kyle Broderick, coordinator of the Plant and Pest Diagnostic Clinic: We're seeing the following diseases:
Soybeans: Phytophthora root and stem and Fusarium wilt have been showing up in a lot of fields, especially in low spots or hillsides due to all of the recent rain. Both look similar (sporadic, wilted plants next to healthy ones); however, one way to tell the difference is Phytophthora tends to cause a lesion that extends up past the soil line while Fusarium wilt does not. Plants with Fusarium wilt will likely have a rotted taproot as well. Have heard reports of brown stem rot and sudden death syndrome occurring, but haven’t been able to confirm.
Corn: Foliar diseases are starting to show up. Gray leaf spot, eyespot, Diplodia leaf streak, northern corn leaf spot, and common rust are the fungal pathogens that have been identified in the clinic. Bacterial leaf streak and Goss’s wilt have shown up as well. A lot of leaf streak is coming in. Know what’s in your field before applying a fungicide. I have talked to three people spraying for gray leaf spot in fields where I could only find bacterial leaf streak. (Fungicides are not effective against bacterial leaf streak.) We are not seeing much southern rust activity to the south, but there have been unconfirmed reports of it in Arkansas. If you suspect southern rust in a field, please send samples so we can diagnose them and alert people as needed. With luck, it'll be a light year for it. (July 10, 2018)
Tamra Jackson-Ziems, Extension Plant Pathologist: I am getting reports from numerous consultants and producers that they’re seeing more bacterial leaf streak than last year, and that in some areas the incidence and severity rivals that of 2016. I’m receiving photos of other diseases that may be Diplodia leaf streak or Northern Corn Leaf Blight, as well as some Goss’s bacterial wilt and blight and Physoderma brown spot.
I’ve also been getting questions about whether to apply fungicide applications in hail-damaged corn. The short answer is "No, it is not recommended." These two CropWatch stories explain why: https://cropwatch.unl.edu/2018/severe-storms-and-hail-damaged-crops-making-right-decision-replants and https://cropwatch.unl.edu/fungicide-use-corn-after-hail-or-wind-damage.
This could be the last year of the bacterial leaf streak survey (and free testing), so please help us document the disease distribution. Bacterial leaf streak has now been confirmed in Saline, Jefferson, and Otoe counties in addition to the previous counties for a total of 63 counties.