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Archive for September, 2012

Gray Leaf Spot is still going strong.

September 27, 2012 Leave a comment

In the past two weeks, just about all I have looked at is Gray Leaf Spot. It is everywhere and at a level I have never seen before in the Northeast. It is probable that much of what we are seeing is because of the very mild winter- much like the mid-Atlantic where this disease is a perennial problem. Gray leaf spot is not very winter hardy and without any winter last year and Hurricane Irene driving much of the disease into our area in 2011, we have more if it than we can handle. A DMI + chlorothalonil application is the best medicine but keep in mind that this late in the season, it will probably hold on until we get a good frost. Slow release granular N will also help turf grow out of the disease (neutral pH, acidifying fertilizers will exacerbate the disease) once the plants get some breathing room following the fungicide application.  And in many cases, the best solution may be to start overseeding now with bent or KBG.

Categories: Weekly Update

Red Leaf Spot too..

September 13, 2012 Leave a comment

In the past week I’ve seen even more gray leaf spot.  It whacked my yard pretty hard and I was forced to go out and put down some granular Eagle before I lost the whole thing.  I just received a sample from Vermont of bengtrass loaded with red leaf spot.  I usually see this in the spring (just a little this spring) but it was raging in 2009, from spring to fall with the cool weather.  I’m not sure how widespread it is but when I first got the pictures, I could have sworn it was dollar spot, the damage was so severe.  But the spores don’t lie….

A DMI is my recommendation.  The strobilurins will also work but it’s an expensive standalone spray to make just for leaf spot.

Categories: Uncategorized

Gray Leaf Spot is on the Move!

September 6, 2012 Leave a comment

In the past week I’ve gotten six different samples that were positive for gray leaf spot from Mass, CT, RI and Long Island.  In at least half of those cases, strobilurins have been used to try and control the disease and failed.   This is not unexpected, gray leaf spot frequently develops resistance to these fungicides (Compass, Heritage, Insignia and Disarm).  The best approach is to tankmix chlorothalonil with a DMI.  High humidity, rain and warm temperatures will drive the disease. It will slow a bit when things cool down and dry out.

Categories: Uncategorized