December is the month when scale insect infestations seem to blow up.
Unfortunately, many people know something’s wrong, but don’t know what. After a month or two, I get a call to ask “what’s the black fungus all over my plant, and how do I get rid of it?”
Well, this year, I would like to keep you from getting to the “black sooty mold” stage. So, take a good look at any plants that are vulnerable to the scale insect in December and January. The list includes but is not limited to …
- Japanese blueberry
- Red tips
- Coppertone loquats
The quickest way to control it is with the insecticide malathion. It smells bad but works great. Despite the odor, it isn’t “organic” by any stretch. But it does have a “food” label on it, and it has been tested and approved for use on fruit trees and vegetable crops for years.
There is, however, a genuine winter-months organic control for scale - dormant oil spray. I believe it to be the only true organic method. There are much lighter oils that have year-round labels, but I don’t think they work near as well. And I have an old “farmer’s almanac-y” recipe that works in the springtime.
But with dormant oil, there is a catch: The plant must be in dormancy for this heavier spray to be effective. If the plant in question looks like it may be growing at all, there’s a lot of respiration/transpiration going on, and a dormant oil spray will suffocate it. So, if you’re going to use a dormant oil spray in the Houston area, we first need a real, bona fide cold front.
Meanwhile, if you spot black sooty mold, don’t panic. Let’s first take care of the insect problem, and get rid of the mold later. My favorite way to beat BSM, is with Consan 20. Spray it on, let it sit for 10 minutes or so, then rinse it off.