Every winter I am plagued by a different pest. This year it's powdery mildew, a white coating on the leaves.It arrived early. Usually there is a respite of a few weeks between the time I bring my plants inside and the outbreak of the bug du jour. Not this year.
And usually it is a bug, not a fungus. But bugs aren't my problem. At least not this year. At least not yet. In the past I've had The Year of the Whitefly, The Year of the Mealybug, The Year of the Aphid and so on. They are fairly easy to handle, often as simple as washing them off occasionally in the sink or the bathtub. Or sometimes a mild insecticide.
Some people think insecticides don't work, but that is usually because they are using them wrong. To kill the critters, you have to hit the critters. They hang out on the underside of the leaves and in the leaf axils, the point where the stem of the leaf meets the main stem. Miss those spots and it is a waste of perfectly good poison.
And you've got to do it several times. Spray once and the bugs come back. You have cruelly killed Mommy and Daddy, but a week later the eggs they had laid hatch out. So you need to catch succeeding generations, eventually getting them all before they lay new eggs. Usually three times at 7 to 10 day intervals does the job.
Here's the problem. The most effective pesticides are labeled for outdoor use only. It's a rule. It's more than a rule. It's a federal law, and using a pesticide in a way that it is not labeled for is a federal offense.
So I would never use such chemicals indoors. No, sir. Not me. Never. It's against the rules. But there is nothing on the label that says you cannot take a plant outside on a day when it is above 32 degrees, spray it quickly, and bring it back inside. Perfectly legal. Ask any tax lawyer how that works.
I got into this mildew trouble because I ran across an August clearance of very sorry looking gerbera daisies, no flowers - so no idea what color they were - just a leaf or two, at 50 cents each. I bought the bunch, paying no more that I would have paid for one in bloom on the bench at the beginning of the season.
Most people think gerberas are annuals and throw them out in September, but they are perennials in their native South Africa. All you have to do is fool them into thinking they're in South Africa. That means decent light, cool temperatures and just enough water to keep them barely alive. They won't look pretty, but they'll come back strong on the patio next summer.
I don't know whether I brought the mildew home with these cut rate daisies or if conditions were just right, but after a couple of weeks indoors they all looked as dusty as my study and most of the leaves were dead. It also attacked a large, sturdy gerbera I had kept for several years.
Many outdoor plants get mildew - lilacs, phlox, monarda - and it does them little harm. But it was killing my gerberas.
There is an organic solution that might actually work. Mix one teaspoon of baking soda in a quart of water with a few drops of dishwashing liquid and spray infected plants regularly. The theory is that mildew doesn't like a high pH. Could be. But I had a fungicide.
The problem is that my fungicide is for outside use and the directions say to mix one ounce to a gallon of water. I had a little 20-ounce trigger sprayer. Uh oh. Math time. I work out the conversion five times, and if I get two answers the same, I go with that. One teaspoon per 20 ounces.
Maybe I'll save my bargain gerberas, maybe I'll lose them. If that's the worst thing that happens this winter, I'll consider myself a lucky gardener.
o Duane Campbell, a nationally known agricultural expert, can be reached at R6, Box 6092, Towanda, PA 18848 or by e-mail at firstname.lastname@example.org for questions or comments.