FHB Alert Blog

FHB Update from US, 05/12/19

There is a large area of the Mid. West that is at moderate and high risk for Fusarium head blight. Local reports from this area indicate that wheat is at or approaching growth stages that are most vulnerable to disease in south central KS, southern MO, Southern IL, Southern IN and KY. Producers in these areas should monitor the weather conditions carefully. Fungicide applications may be needed to suppress disease in these areas. Selecting the state of interest from the menu to the left of the map will zoom to show more detail and display commentary from local disease specialists.

--Erick DeWolf, Extension Plant Pathologist, Kansas State University

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

FHB Update from MD, 05/10/19

Wheat in the Eastern Shore of Maryland is finishing up flowering. The risk for FHB is high. If you haven’t sprayed and you are still within 4-5 days of flowering, you can still do so. Wheat in the Northern parts is heading now and will soon start flowering. The FHB risk for this part of the state is also predicted to be high, and the farmers should be prepared to spray fungicides on their wheat when it flowers (50% of the main tillers showing yellow anthers). The fungicides effective for FHB are Prosaro/ Caramba/ Miravis-Ace. The best stage recommended for spraying fungicides is early flowering or within 4-5 days of that. These fungicides do not need to be tank mixed with another product for spraying. The fungicide products should be applied at the full rate recommended by the manufacturers. Strobilurin containing fungicides should not be sprayed at this stage. Aerial application at a rate of 5 gallons per acre or ground application at 15 gallons per acre with 300-350 um droplet size is recommended. Spray nozzles should be angled at 30°-45° down from horizontal, toward the grain heads, using forward- and backward mounted nozzles or nozzles with a two directional spray, such as Twinjet nozzles. There has been no other major disease being seen anywhere across the state in wheat so far.

--Nidhi Rawat, Small grains Pathologist, University of Maryland

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

FHB Update from OK, 05/09/19

This past week in addition to looking at wheat around Stillwater, Dr. Tom Royer (OSU Entomologist) and I were at field days on Monday (6-May) near Kildare in north-central OK (Kay County) followed by a stop at the Experiment Station near Lahoma (15 miles west of Enid) and another field day near Cherokee in Alfalfa County (north and west of Enid and about 20 miles south of KS). That was followed on Tuesday by a field day at Kingfisher (about 25 miles northwest of Oklahoma City) and field visits northwest of Kingfisher near Loyal. Across these areas wheat ranged from heading to full kernel formed (watery to start of milky). In southwestern OK, wheat ranges from ¼ kernel to milky whole kernels with the dough stages approaching quickly.

In southwestern OK, leaf rust, stripe rust and Septoria tritici blotch have become severe according to both Heath Sanders (SW OK Area Extn Agronomy Spclt) and Gary Strickland (Extn Educator; Jackson Cnty). Gary indicated that this is only the second time he has seen Septoria tritici blotch severe on flag leaves. Leaf rust also is severe. Both Heath and Gary also indicate they have started to see more powdery mildew in fields, but have found it severe on the mid and lower leaves in only one field.

In north-central OK near Kildare, wheat was mostly clean with Septoria tritici blotch being the most noticeable disease on lower leaves. No significant stripe or leaf rust was observed, and powdery mildew could be found but was sparse. By contrast, wheat at Lahoma showed significant leaf and stripe rust with leaf rust being the most prevalent. However, whereas the rusts could be found in many of the wheat breeding nurseries, both rusts were lacking in the large variety trial with stripe rust being present at only a low severity. In some varieties and breeder lines, leaves were quickly deteriorating. At Cherokee, heavy rain on Sunday had saturated the area and more rain fell on Wednesday. Rust was light in the variety trial with stripe rust again being the most prevalent albeit again at a low incidence and severity. At Kingfisher on Tuesday, leaf rust was the most prevalent foliar disease with Septoria tritici blotch also present on lower foliage. In a field near Loyal, OK, Dr. Royer found a high incidence of armyworms especially along the field’s edge. As he moved into the field, the incidence of worms dropped, but he felt like a field such as this was approaching the spray threshold and should be watched closely to monitor if the spray threshold was reached. For more information on armyworms in wheat, including threshold numbers and control options, see Pest eAlert Vol 18, No. 14, EPP-7094 “Common Small Grain Caterpillars in Oklahoma” and CR-7194, “Management of Insect and Mite Pests in Small Grains.”

In addition to army worms, a physiological leaf spot (PLS) was observed on wheat leaves around Kingfisher and Loyal. As indicated in my last update (http://entoplp.okstate.edu/pddl/2019/PA 18-16.pdf), PLS has been observed in a number of fields across several varieties. There can be many causes of PLS, one of which is chloride deficiency. Chloride deficiency tends to be variety specific. Years ago in Oklahoma, the varieties ‘Payne’, ‘Cimarron’ and ‘Century’ all would show PLS due to chloride deficiency. Cimarron and Century both had Payne as a parent in their pedigree. Hence, although chloride deficiency can cause a PLS, there are other causes as well, and this year I believe that the PLS being observed is too widespread and across to many varieties to be attributed to only a deficiency of chloride. For more information on chloride and its role in PLS, see Kansas State University’s recent extension publication MF 2570; Chloride in Kansas: Plant, Soil and Fertilizer Considerations (Dorivar A. Ruiz Diaz), which can be found at: https://www.bookstore.ksre.ksu.edu/pubs/MF2570.pdf

A report of increasing foliar disease also came in from Lanie Hale (Wheeler Brothers; west central OK) who reported, “In my last report April 26, I told you I found 3 fields with rust. Those 3 fields were out of a total of 23 fields scouted. Those 3 fields have been sprayed. Yesterday, May 6th, I looked at the 20 fields where I found no rust April 25th. 11 of those 20 had stripe rust and/or leaf rust. Since the 30 day window is upon us, the farmers are spraying all 20 fields. In the fields I looked at yesterday, I would estimate 75-80% of the flag leaves had some kind of dis-coloring issue ranging from light flecking to stripe rust, leaf rust, Tan Spot, or Septoria tritici blotch. (1&2) I noticed many of the stems have dark spots below the flag leaf; (2) I’m assuming that is also Septoria tritici blotch. Several fields had small circular spots that appear to be Barley Yellow Dwarf Virus hot spots. (3) The head count in all the fields I’ve scouted, regardless of the location, is tremendous. If we can maintain the flag leaf health we have today, yields and grain quality will also be tremendous.”

These and additional reporting by Josh Bushong (NW OK Area Extn Agronomy Spclt) all indicate that foliar wheat diseases, especially Septoria tritici blotch, leaf rust, and stripe rust are increasing greatly in incidence and severity across Oklahoma. With continued wet and cool weather, the incidence/severity of these diseases will continue to increase across northern OK and the OK panhandle. The spraying window across much of Oklahoma is now getting quite tight, and a producer needs to be certain to follow the fungicide label regarding when a fungicide can be applied in order to be in compliance with the label. For more information on applying fungicides and their relative effectiveness in managing foliar diseases, see OCES Current Report (CR-7668) that can be found at: http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-4987/CR-7668w...

Finally, in addition to the rusts, Septoria tritici blotch and powdery mildew, other diseases that have been observed include an occasional loose smutted head as observed by Zack Meyer (Sales Agronomist with CHS) near Hennessey, OK. I also have seen an occasional head of loose smut this year in various fields. It merits to mention that if you see loose smut or common bunt in a field, do not save seed from that field for planting the next year as that will lead to increasing that smut or bunt. If that field is planted again in wheat, be sure to plant seed treat at a high rate with a fungicide effective against the bunts and smuts. Barley yellow dwarf also has been seen in various fields and trials around the state but is much less prevalent than typical as are the mite-transmitted viruses, especially wheat streak mosaic virus.

--Bob Hunger, Extension Plant Pathologist, Oklahoma State University

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

FHB Update from IN, 05/09/19

Wheat is starting to flower in southern Indiana. Recent weather has continued to favor a forecast of high risk potential of infection for most of the state. It is time to consider your spray options for wheat if Fusarium head blight is a concern. The best time to make a fungicide application is when 50% of heads are starting to flower – watch for anthers (flowers) emerging from the wheat heads to make this determination. The best control, with all fungicides, will occur when applications are made at this time. Caramba and Prosaro (FRAC group 3) or Miravis Ace (FRAC group 3 + 7) give good control of scab as well as most leaf and head diseases."

--dtelenko, Extension Plant Pathologist, Purdue University

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

FHB Update from PA, 05/09/19

Wheat that is flowering now or in the next several days in southern PA should be sprayed for scab if at all possible. Weather conditions are conducive for infection in most regions of the state. If spraying at early flowering is not possible, a fungicide application up to 6 days later will provide some suppression of the disease. Keep an eye on your label to understand post-harvest interval restrictions.

--Alyssa Collins, Extension Field Crops Pathologist, Penn State University

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

FHB Update from MO, 05/08/19

Prolonged wet weather has lingered over much of the state in the past few weeks as the southern half of the state approached flowering and is predicted into the coming week as the northern half of the approaches flowering. At this time, conditions in much of the state place the more susceptible winter wheat varieties at high risk for FHB development. Moderate risk levels are predicted for the moderately susceptible and moderately resistant varieties are at moderate risk. Into the coming week, humidity is expected to remain high across much of the state meaning the risk for FHB development remains high likely into the coming week. Now is the critical time to make decisions regarding fungicide applications. There are several fungicides labeled for the control and management of FHB in the triazole class (including Prosaro and Caramba) which are most effective when applied at Feekes 10.5.1 (50% of the plants in the field are beginning to flower). While fungicides provide the most effective control when applied at Feekes 10.5.1, university research has shown that a fungicide applied up to 5 days after Feekes 10.5.1 may provide similar control. It is important to note that strobilurin-containing fungicides are not labelled for control of Fusarium head blight and, if applied at later growth stages such as Feekes 10.5.1, may result in increased DON levels in the grain. Always follow harvest restrictions and label instructions when applying fungicides.

--Kaitlyn Bissonnette, Extension Plant Pathologist, University of Missouri

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

FHB Update from VA, 05/07/19

Fusarium head blight risk is continuing to increase in parts of Virginia. Much of the wheat in the southern part of the state is past the vulnerable flowering stage, but wheat that is at or about to enter flowering may be at risk. Consider applying a fungicide if risk is moderate to high, especially on susceptible or moderately susceptible varieties. Wheat that has completed flowering is no longer at risk. Fungicides should be applied at early flowering or up to one week later. Do not apply a strobilurin-containing fungicide since this can increase DON contamination. Recommended fungicides include Prosaro, Caramba, Proline, and Miravis Ace.

--Hillary Mehl, Extension Plant Pathologist, Virginia Tech

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

FHB Update from US, 05/07/19

There is a large area of the Mid.West that is at moderate and high risk for Fusarium head blight. Local reports from this area indicate that wheat is at or approaching growth stages that are most vulnerable to disease in southeastern KS, southern MO, Southern IL, and parts of KY. Producers in these areas should monitor the weather conditions carefully. Fungicide applications may be needed to suppress disease in these areas. Selecting the state of interest from the menu to the left of the map will zoom the map to show more detail and display commentary from local disease specialists.

--Erick DeWolf, Extension Plant Pathologist, Kansas State University

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

FHB Update from KS, 05/07/19

Wheat in southeastern and south-central Kansas is at heading stages of development. Wheat in these areas will reach the growth stages critical for Fusarium in roughly week to 3-5 days. The model is indicating moderate or high risk of severe disease just as we head into the most vulnerable period of growth. The risk is likely to persist or increase if these regions continue to receive frequent rainfall and extended periods of high relative humidity. Growers in southeastern and south central Kansas should be monitoring situation carefully and planning to apply a fungicide if weather conditions remain favorable. Care should be taken to select an effective fungicide for management of FHB with Prosaro, Caramba and Miravis Ace being the best options. Many other fungicides are less effective or are not labeled for Fusarium suppression.

--Erick DeWolf, Extension Plant Pathologist, Kansas State University

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

FHB Update from KY, 05/06/19

Wheat fields in Kentucky are now either at beginning flowering (Feekes growth stage 10.5.1) or within a few days past Feekes 10.5.1. Due to the recent rain events, the risk of Fusarium head blight has elevated to medium and high in a few areas of the state. Fungicides that are effective in managing Fusarium head blight and the associated mycotoxin, deoxynivalenol (DON; vomitoxin) include Caramba (BASF Corp.), Prosaro (Bayer CropScience), and Miravis Ace (Syngenta Crop Protection). In general, in university research trials, the most effective application timing for management of Fusarium head blight and DON has been Feekes 10.5.1 (beginning flowering), but applications 4-6 days after Feekes 10.5.1 also have been found to be similarly effective. Be sure to read and follow fungicide labels, including pre-harvest interval restrictions before making any fungicide applications.

--Carl Bradley, Extension Plant Pathologist, University of Kentucky

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

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