07/18/2012
Temperatures are set to be high again this week with maximum temperatures forecasted from the high 80s to mid 90s. Humidity will be lower than we have seen in the past week. Most of the wheat crop is now in the soft to hard dough stage of development.
With the warmer weather, stripe rust is finally entering the resting stage of its life cycle evident as black telial pustules on leaves. Leaf rust incidence is moving North and West through the state with the highest incidences (up to 100%) and severities (up to 30%) being reported in Otter Tail county.
Incidence of tan spot is on the increase as well – in some cases 100%,of affected – with low to moderate severity. This trend is likely to continue in the central and eastern parts of the state over the next few days.
Risk of leaf rust in the central and eastern part of the state will trend much higher in the next couple of days. The risk for tan spot remains high throughout the state.
Scab risk remains moderate to high in the north west of the state. Initial reports of scab infections have been confirmed, especially in the most northwestern portion of the State. This is the same area for which the risk model had shown a moderate risk for FHB 2 to 3 weeks ago. Incidence and severity are low at this point.
–Jochum Wiersma, Small Grains Specialist, University of Minnesota
For more details, go to the FHB Risk Assessment Tool at http://www.wheatscab.psu.edu/riskTool_2012.html
Some moderate to high risk for FHB susceptible wheat varieties still exists in the northern counties of Cavalier, Towner and Rolette and in the Devils Lake region. However, few if any, late planted wheat will still be in the flowering stage, the stage of vulnerability to infection. This will be the last commentary for the season on the FHB alert, as the vast majority of crops are now in kernel fill stage or beyond. Overall, FHB (scab)has been minimal across the state in crops surveyed up to now.
–Marcia McMullen, Extension Plant Pathologist, North Dakota State University
For more details, go to the FHB Risk Assessment Tool at http://www.wheatscab.psu.edu/riskTool_2012.html
Winter wheat harvesting is continuing across the state with some reports from the south central area of the state having around 80-100 bu/A with test weights of around 60-63 lbs/bu and good proteins. Low DON amounts (below 1 ppm) have also been reported. Spring wheat harvest will be starting soon if not already started in some areas of the state.
Kay Ruden, Extension/Research Associate, Extension Plant Pathology, South Dakota State University
–SDSU Extension Agronomists and Breeders, , South Dakota State University
For more details, go to the FHB Risk Assessment Tool at http://www.wheatscab.psu.edu/riskTool_2012.html
07/10/2012
Temperatures are set to be slightly cooler this week than last, and expected to stay in the low to mid 80s. Humidity will be lower than we have seen in the past week. Most of the wheat crop is now in the late milk early dough stage of development.
Stripe rust is still prevalent across the state. However weather conditions are now becoming favorable for development of leaf rust which is evident in the south and west of the state with severity ranging from moderate to severe. Sibley county being the worst affected at present. Septoria diseases have progressed with 100% of some fields affected with moderate to high severity.
Risk of leaf rust in the central and eastern part of the state will trend much higher in the next couple of days . The risk for tan spot remains high throughout the state. Scab risk remains moderate to high in the north west of the state.
Reports of fields with a unusual amount of dead heads with little or no grain have been reaching us. Incidences as high as 15-20% have been reported. We are sampling some of the worst fields to determine the exact cause or causes and will share those results as they become available.
–Jochum Wiersma, Small Grains Specialist, University of Minnesota
For more details, go to the FHB Risk Assessment Tool at http://www.wheatscab.psu.edu/riskTool_2012.html
Some moderate risk for FHB susceptible wheat varieties still exists in Cavalier, Towner and Rolette counties and around Devils Lake. Most wheat is well past flowering stage, but growers with any late planted fields of FHB susceptible varieties should consider the risk of FHB in those fields and application of appropriate fungicides at flowering.
–Marcia McMullen, Extension Plant Pathologist, North Dakota State University
For more details, go to the FHB Risk Assessment Tool at http://www.wheatscab.psu.edu/riskTool_2012.html
07/02/2012
Weather conditions have been getting steadily warmer over the last week, routinely in the mid-80s° F. This trend is set to continue over the next week with temperatures reaching the low 90s° F. This unusually dry and warm weather is having a direct impact on the range and severity of diseases and plants reactions to other stresses such as herbicide drift and drought. With the majority of wheat in the end of milk and into the early dough stage, many plants are clearly showing evidence of heat stress. This heat stress is exacerbating other diseases that are not normally prevalent.
Stripe rust is still very evident across the state with high severity on spring and winter wheat in to the mid canopy. A number of fungicides will give good control of stripe rust provided they are applied before symptoms are evident on the flag leaf. Fungicide application will not cure already visible or latent infections. Although the warm temperatures will slow stripe rust development, cooler night time temperatures and the chance of stormy precipitation, will allow this disease to continue. If generic Folicur, Prosaro or Caramba were already applied at Feekes 10.51 to suppress scab, you can expect sufficient control for the remainder of the growing season for stripe rust.
Septoria species are also becoming prevalent in the west central portion of the state with low – mid severity on 20-50% in the fields scouted. Evidence of wheat stem maggot is now appearing in the south-west of the state. Typical symptoms of damage caused by this insect are white or blasted heads which will produce no grain, while the rest of the plants looks normal. The head can easily be pulled from the plant to reveal the feeding damage.
Because of the weather, the risk of scab is likely to be very low over the next week. These same conditions are more conducive to stem rust and leaf rust may become more evident, especially in the southern part of the state.
–Jochum Wiersma, Small Grains Specialist, University of Minnesota
For more details, go to the FHB Risk Assessment Tool at http://www.wheatscab.psu.edu/riskTool_2012.html
Due to high temperatures across the state this week, there is low risk for Fusarium head blight for any wheat that happens to still be flowering. Also, due to the heat, the wheat across the state has been maturing quickly. The harvesting of winter wheat started last week in the central part of South Dakota.
Kay Ruden, Extension/Research Associate, Extension Plant Pathology, South Dakota State University
–SDSU Extension Agronomists and Breeders, , South Dakota State University
For more details, go to the FHB Risk Assessment Tool at http://www.wheatscab.psu.edu/riskTool_2012.html
High temperatures over the weekend, and continued predicted high temperatures have reduced the risk of FHB across the state. Wheat crops are maturing quickly with the very hot temperatures.
–Marcia McMullen, Extension Plant Pathologist, North Dakota State University
For more details, go to the FHB Risk Assessment Tool at http://www.wheatscab.psu.edu/riskTool_2012.html
There is medium risk of Fusarium head blight forecasted for the next few days for parts of eastern and northeast South Dakota for any spring wheat varieties that are still flowering. The rest of the state is at a low risk for the next few days.
Kay Ruden, Extension/Research Associate, Extension Plant Pathology, South Dakota State University
–SDSU Extension Agronomists and Breeders, , South Dakota State University
For more details, go to the FHB Risk Assessment Tool at http://www.wheatscab.psu.edu/riskTool_2012.html
Some moderate to high risk of Fusarium head blight infection still exists for susceptible cultivars in the northern tier of counties of ND. Today”s conditions are very windy, which should dry out the top of the canopy, but checks of weather data at Langdon, Cavalier and Minot showed very high dew points in these locations at 1:00 pm on June 26. The forecasting site indicates that risk of Fusarium head blight will diminish in these areas as the week progresses. Stripe rust levels have increased in these areas, because of their relatively cooler temperatures and longer dew periods than much of the state.
–Marcia McMullen, Extension Plant Pathologist, North Dakota State University
For more details, go to the FHB Risk Assessment Tool at http://www.wheatscab.psu.edu/riskTool_2012.html
