Thought 1, thrips
Thought 2, mites

The damage looks like scraping to me on my phone here, a usually sure fire sign of thrips. Not just flower attackers.

I haven't seen any insects on the plants, which have been sprayed regularly with Neem. I am thinking that whatever it is was introduced by the beetles (Tenthecoris) six months back. They made a beeline for the Catts. I guess they prefer the local food. I've resprayed with wood vinegar, in case it is something resistant to Neem, though that has always been a good protection for me, and introduced a strict quarantine regime. All the Catts, Epis and relatives have been removed and the ones least affected mounted on plaques or tied into trees and spread around the garden. The sick ones are in "isolation ward" next to the toilet!! The prognosis for them is not good, however. The shelves are looking rather bare, but there doesn't seem to be any alternative. Altogether I will have lost about 75 (a quarter) of the plants. Don't lose your sleep,however.Tenthecoris is rarely found in collections as it cannot survive outside the tropics. - Ian.

Mites and Thrips is my guess. They are under the leaves and when you spray you need to spray the under surface of the leaves. Use 2 agents and spray alternating x 4 weeks. Make sure you spray the uindersurface , everything else is useless. I'm in the middle of a spraying session alternating AVID and Malathion. After complete eradication they recommend spraying once a month a year, probably optional.

Nick

Jane, if it was mites the imidacloprid would not have done a thing for it; imidacloprid operates in a way that has no effect on arachnids.

Ian, check your logic. If believe it was something introduce by the beetles, why are you using a pesticide? If you dont think its mites/thrips, and you think it's a disease you need to be using fungicide!

Thanks Terp. Maybe it is thrips because the Bayer works (so far). I went on the assumption that it was false spider mites because the flowers were not affected.

I appreciate your information. Big mistake on my part, I didn't check the list on the Bayer product.

Jane

Nope, I think it's a bacterium, introduced by the insect vector. I am strictly organic - sorry if that makes me sound Hassidic - the fact of the matter is that many "advanced" chemicals are extremely expensive here and since I have no guarantee they will work, as I still don't know exactly what I am fighting, my only two options are Neem, which also has anti-bacterial and fungicidal properties but to which it seems to be resistant, and an old Japanese remedy, wood vinegar. If you know of any others....
This has been quite a difficult case to solve. I can assure you I have spent quite a long time exercising my logical faculties.I will let you know how it turns out. - Ian.

editing

This post was edited by terpguy on Sun, Aug 25, 13 at 22:58

Ian, if you think it is bacterial you need to trow out the plants immediately. There are no products available to hobbyists that are anti bacterial, at least here in the US. Those that do exist all require pesticide license to purchase, possibly even a business license. Very powerful and dangerous chemicals. Neem will NOT do the trick, make no mistake about that. So I recommend quitting that immediately. It is insecticidal, nothing more.

But I question the bacterial diagnosis. Most bacterial infections to my knowledge are going to have wet, watery symptoms and take over the plant in such a syndrome that would not allow to plant to grow how it looks now. This doesn't scream bacterial infection to me at all. Much of the damage in the photo appears mechanical to me.

No problem Jane. It's a big point all hobbyists have to learn: what's good for the goose is never good for the gander :)

This post was edited by terpguy on Sun, Aug 25, 13 at 23:01