By Blake Jackson
Brown stripe, sometimes referred to as leaf streak, is a common disease affecting orchardgrass and several other forage grasses in Kentucky.
According to University of Kentucky specialists Kiersten Wise, Julie Beale, and Jonathan Oakes, severe infections can reduce both the yield and nutritional quality of forage, making disease awareness and management important for producers.
The disease typically begins with small gray-to-brown spots on leaves. These lesions may be circular or elongated and can expand several inches depending on the grass species and its susceptibility.
As the disease progresses, multiple lesions may merge, causing large portions of leaf blades to turn brown. In advanced cases, much of the foliage may appear scorched.
Another identifying feature is the presence of black fungal spore structures that develop in rows within established lesions or along damaged leaf tissue.
Brown stripe is caused by the fungus Graminopassalora graminis, which infects a wide range of grass species. Besides orchardgrass, important hosts in Kentucky include tall fescue, timothy, and bromegrasses. The pathogen is not considered a concern for corn, sorghum, or small grain crops.
The fungus survives in infected plant debris and leaf tissue. During wet spring conditions, spores are released and spread through rain splash and wind-driven moisture.
Disease development is favored by cool, damp weather, while hot and dry conditions tend to slow up new infections.
However, symptoms often become more noticeable during summer when drought stress weakens infected plants. Additional diseases may then invade, increasing damage and causing premature leaf death.
Producers can reduce disease impacts through sound management practices. Following soil test recommendations for fertilizer applications, avoiding excessive nitrogen, controlling weeds, and harvesting forage in a timely manner can help minimize stress on plants.
Newer orchardgrass varieties may offer improved performance, and fields with confirmed infections may benefit from a two-year rotation to non-grass crops.
While fungicides are available, limited research and economic returns generally make them a less practical management option.
Photo Credit: pexels-mattycphoto
Categories: Kentucky, Crops, Hay & Forage, Harvesting