Leaf scald on barley leaves. Diseased leaves have water-soaked, pale or dark-gray blotches with brown margins. Lesions can eventually take over the entire leaf surface.
Barley scald, caused by the fungus Rhynchosporium secalis, can infect barley, rye and wild grasses. Scald is more likely to be severe during years with higher-than-normal rainfall. Cool temperatures ranging from 40 to 77 degrees F favor barley scald development, infection and spread within a field.
Identification and Lifecycle
Barley scald can occur any time during the season. It can develop on leaves, shafts and glumes. Diseased leaves will show water-soaked blotches that appear pale or dark gray with brown margins. Entire leaf surfaces may gradually become covered with lesions, inhibiting photosynthesis and nutrient uptake. While barley scald usually infects only leaves, the disease may develop on spikes and up to the glume when infection is widespread.
During cool, rainy weather, spores develop on leaf lesions to create a thin, slimy layer. Spores travel from plant to plant by wind-driven or splashed rain. If leaf surfaces stay wet for 24 hours, spores will germinate and infect the leaves where they have landed. While barley scald disease stops when weather becomes hot and dry, new infections can develop in the fall. The barley scald fungus can overwinter on barley crop residue, volunteer barley, infected seed and grasses.
Barley scald can be one of the most damaging diseases to barley crops in optimal conditions. When infestations are severe, the disease can cause up to 30 to 40 percent yield losses, reduced grain quality and discounted prices at the elevator.
Enlarged lesions can kill barley leaves, resulting in rapid scalding that causes leaves to dry out and turn brown. Typically, early-planted barley is most susceptible to barley scald disease because infected crop residues release the highest spore populations. Potassium deficiency and high levels of nitrogen can also contribute to a higher level of foliar diseases in cereal grains.
Managing Barley Scald
Farmers have several options to manage barley scald:
Check for the presence of barley scald and other leaf diseases when scouting for weeds and insects. Scouting helps you decide whether or not a fungicide application is needed and provides information to help you select appropriate disease management practices for future crops. If you suspect barley scald, take samples and work with your county Extension agent to confirm a diagnosis. Crop identification guides are also helpful.
Rotate crops to help deter diseases. In areas where continuous barley is grown, cultivation can break down crop residue that harbors certain diseases. Plant disease-free seed. Control weeds during preplant, at planting and throughout the growing season to help protect against disease and other pests.
Apply fungicide for barley scald and other foliar diseases based on symptoms discovered while scouting. Assess disease severity from the early seedling growth stage through spike. Time your fungicide application to keep the upper leaves of the barley plant disease-free, allowing full potential for grain fill. Other factors affecting fungicide application are infection levels in the field, the susceptibility of the variety and the market price for barley grain.
Bayer Solutions for Barley
With a combination of two chemistries, triazoles and strobilurins, Prosaro® fungicide from Bayer provides preventive and curative action against barley scald and other key cereal leaf diseases, including various types of rust, Septoria leaf blotch, tan spot and powdery mildew. Additionally, Prosaro provides unsurpassed activity against head diseases such as scab (Fusarium head blight). It’s a good choice to ensure grain quality and enhance yield potential.
For information on a portfolio of products from Bayer to help barley growers maximize yields and protect their crops, visit Top Tips for Barley Yields or contact your local Bayer representative.