Question: Several of my violets have tight centers and hairy leaves. I may have overfertilized when I switched fertilizers. But when I read my magazine, the description of tight centers and hairy leaves seems to come up when describing cyclamen mites. How do I tell the difference? I do have misshapen blossoms on some plants, but thought maybe condensation was taking place.
Answer: It’s hard to know for sure, since so many things can cause these symptoms. A cyclamen mite infestation is the easiest conclusion to jump to but, fortunately, it’s often the wrong one. If it is only a fertilizer problem, try leaching the plant by running clear water through the soil, then watering without fertilizer for a short period. The tight center growth should begin to loosen. Another possibility is environmental. Both very warm or very cold temperatures can cause tight centers, though “hairiness” of the leaves makes cold temperatures more likely here. Are these plants near a drafty window or in a cold corner of the basement? Too much light can cause tight centers, too.
Cyclamen mites are very tiny insects, visible only under magnification, being less than 1/100th of an inch long. They can be eradicated with minimal plant damage, if the infestation is caught in an early stage. On the occasions that we’ve had to deal with this pest, we’ve had to use chemicals to eliminate them (yes, we do use chemicals, but only when absolutely necessary). We’ve had good success with Avid, which seems to be the miticide of choice among larger commercial growers. Unfortunately, it is costly ($70 or more for 8 oz.) and comes in quantities that most small growers won’t be able to use. Given its cost, we wouldn’t advise the small, hobby, grower to expose themselves to toxins for the sake of a few violets.
In any event, we’d suggest that you separate your problem plants from your healthy ones. Investigate one possibility at at time. If the problem is bad (i.e. more like mites), root some healthy leaves and throw out the plants. Wash the leaves in a mild soap (like Ivory) and room-temperature water before rooting, and segregate the resulting plantlets until you are sure that they, too, haven’t inherited the problem. If you must use a chemical, follow all instructions and take every precaution for safety. Since their life cycle is about 14 days, repeated treatments will be necessary to eradicate them–say, at least 3 applications at weekly intervals.