Recent reports bring to mind that warm and wet spring weather is perfect for development of the bacterial disease known as fireblight in susceptible hosts. Fireblight is caused by Erwinia amylovora, a bacterium that only affects plants in the rose family (Rosaceae). Some common hosts include apple, crabapple, cotoneaster, hawthorn, mountain ash, pyracantha, and pear.
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Fireblight in Ornamental Rosaceae
Red Thread Disease is Active
By Jim Murphy
Several weeks ago the cool wet weather brought on some red thread disease activity that has increased over the past 4 to 5 days. Turfs under low maintenance, particularly low nitrogen fertility, have been the areas with the greatest amount of red thread. This disease has been active on on slender and strong creeping red fescues, Chewings fescue, velvet bentgrass, perennial ryegrass, and tall fescue this spring. [Read more…]
Crabgrass is Emerging
By Jim Murphy
Very small first and second leaves of emerging crabgrass can be seen now in open turf areas.
During the last couple weeks, we have seen crabgrass emerging from open turf areas that were previously infested with crabgrass. Crabgrass emergence will probably occur later than this on better maintained turfs with a dense canopy.
Seeing Red, Feeling Blue?
Red thread has been festering in turfgrass for some weeks now, but really blew up over the last few days. As long as there is plenty of moisture – light rain, heavy fogs, dew – and optimal temperatures (60ºF to- 75ºF) – the fungus that causes red thread, Laetisaria fuciformis, will tear up susceptible grasses.
Brown Ring Patch
Several samples of brown ring patch found their way into the Plant Diagnostic Laboratory this week. Sometimes confused with take-all, fairy ring, or yellow patch, this relatively newly described malady of Poa annua putting greens is caused by the fungus Waitea circinata.
Bizzaro World
The crew of the Plant Diagnostic Laboratory are always on the hunt for new and exciting examples of plant damage. Last week, out walking her dog, Sabrina Tirpak our Principle Technician and photographer happened upon a red maple with these amazing red leaf spots.