Blight On Lawns

Turf-killing diseases, like leaf blight, got an early start this year thanks to a wet spring and are quickly spreading across lawns. 75 percent to 80 percent of lawns infected by the disease will recover on their own. If it doesn't, wait until September, mow the brown patches really short, run an aerator over them, rip up the blotchy grass and plant new seed.

Many landscapers put down synthetic fertilizers that include salt and other chemicals that kill biological diversity and ultimately do more harm than good.

''The end result is that they are reducing, slowly but surely over time, the biological diversity whose sole purpose in life is to aerate soil and antagonistically compete with disease-causing pathogens,'' Said Eric Morgan of Lancaster-based Organic Approach. He said many of the most pockmarked lawns can be found in new developments.

''This is one of the worst cases I've seen in lawns in almost 25 years of managing turf,'' said Jeff Hazlett, the owner of Ever Green Tree & Lawn Care in Lancaster, Pennsylvania ''It's kind of unprecedented. I've never seen this much damage to turf.''

The primary disease, ascochyta, has shown up in yards this summer, creating large irregular patches of yellowed grass. Often, leaves infected with the fungus show bleached tips a third to halfway down the blade, according to Colorado State University's extension. The part of the leaf separating the healthy and diseased sections is abrupt and slightly pinched.

''It kills it from the tip of the leaf blade down, and, basically, it's the top of the plant that gets killed,'' Hazlett said. ''Ascochyta is among five common yard diseases that are thriving this year,'' said Jim Welshans, a turf-grass specialist and educator with the Penn State Agricultural cooperative extension. ''With this humidity, I've seen a lot of diseases out there,'' he said. ''It's been a challenging year for growing turf-grass.'' So if you've got brown spots in your yard, what should you do? For now, do nothing. Turning on the sprinkler won't work.

''Grass seed is like any other seed,'' Welshans said. ''It needs soil contact to germinate. Too many times people just go out and throw it on top of the grass and then it doesn't germinate.''