MORE PLAGUES --PART ONE

     We have experienced more plagues this summer than just drought. One of them has been an explosion of powdery mildew. A traditional enemy of common  lilacs, this fungus attacks many shrubs, perennials, fruits and vegetables. The nursery industry has devoted many years to developing mildew-resistant strains of your favorite plants, and this has been a big help. Proper housekeeping and clean-up by home-owners, especially at the end of the season, also helps. For most people powdery mildew has been only an occasional problem on some plants.

     Not this year. There is now powdery mildew in almost every yard. Peonies and phlox have been particularly hard-hit. The problem started, I believe, during the monsoons of last summer, when all our rainfall and humidity allowed the disease to gain new foot-holds. By the time we began to notice problems, the season was drawing to a close, so most of us did not do much about it. The mildew had a chance to create its spores, and they  in turn had a wonderfully easy time surviving our mild winter. The result is the minor epidemic we see now. And all the recent watering we have done with sprinklers has spread the fungus even more. One of the first things you can do to resist powdery mildew is to replace your sprinklers with soaker hoses in your shrub and perennial beds.

     Powdery mildew is easy to spot, as you can tell from the photograph. It harms fruit and vegetable production. For most plants it is disabling, but not fatal. It is, of course, disfiguring. Some of us have lived with our old mildewed lilacs for years, but other plants can be too ugly to look at.

     The first step in controlling this pest is pruning. You should prune out as much diseased foliage as is practical, and, while you are at it, prune the area to thin and to increase air circulation as well. The leaves should not be composted. They are covered with spores that can spread the disease elsewhere. For badly infected perennials that have already bloomed (like peonies), it is probably better to cut the entire plant to the ground and wait for next year. Clean the ground around the plants thoroughly as well and remove any mulch you have in the immediate area. Again, remember those spores.

     As for treatment, organic methods, are, as usual, more work and less effective than others, but still worth trying first. The easiest is to mix 1/2 tsp. of baking soda with a quart of water and spray regularly. This increases the leaves' PH and makes them more inhospitable to the fungus. Neets  oil is also recommended by some. Sulfur is one of the most effective  treatments for garden diseases. You can make  your own sulfur solution  with a garlic press, a strainer and a quart of water. Garlic has a high sulfur content.

     If you are discouraged by this, you can always "nuke 'em" by using a commercial fungicide that contains sulfur or triforine. Read the label carefully. While toxic in liquid form, many are much less so once they have dried. It is worth mentioning that even these products don't "cure"what is already damaged; they just prevent new damage. And they are most effective when the fungus is first evident.

     In short there are no miracles here. To have a better season next year you need first to clean up thoroughly this fall. Then look for disease resistant cultivars when you buy new plants next spring. Use soaker hoses. And thin your plants to get plenty of air circulating. After all, how much garlic do you want to crush when you can not even eat it?