My streps have really suffered this summer and I thought I'd ask here to see if anybody had seen this problem before. The ends of the leaves turn grayish and look a little fuzzy. It spreads most quickly along the sides of the leaf toward the center of the plant. I believe it is some kind of fungal disease? I've been chopping away, trying to remove the bad leaf parts, with some limited success. The leaf dies and stays grayish. On one plant much darker sections appeared, away from the ends. That plant got so bad I tossed it.
I have a bunch of other gesneriads, from an AGGS seed package, and they are all doing fine (except the strep seedlings, which died!) Actually I have one unifoliate (monocarpic) plant which may be a strep, and it is doing well. Lots of sinningias that are doing great also. An African violet has been blooming and growing all summer. Whatever this problem is, it seems to target the rosalate streps only (so far.)
Could it be heat related? Central Texas summers are long and hot. I keep the room around 78-80. The plant area near the window may get up to 80-84. It doesn't cool off much at night- plant area may get to 78 at night.
Could it be air flow? I have a ceiling fan in the room always running, but some shelves get more air flow than others. The shelf with the misc. gessies probably gets the most air flow.
I'm very careful with watering, I don't think overwatering is a problem. I could take a leaf sample to work here and look under a microscope- anybody know what to look for?
I tried Neem oil at one point and it may have helped- I will try it some more. (I'd use it more but having to mix it each time is bit of a PITA for a busy guy like me:) Also it stinks and the plant room is also my bedroom.)
It will start to cool off in a few weeks here- I hope that they perk up. It would be nice to see them bloom- some have tried to bloom, but the plants are so small and scraggly I've been disbudding them...
Sorry for the length- I wanted to give details but maybe went overboard.... Anybody got any ideas/comments? Want to see a photo?
Andy in Austin