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This is a discussion on Rhyncostylis gigantea (arrived with purple circles) within the Orchid Ailments / The Compost Pile forums, part of the Orchid Culture category; Jenn, those look different to me, not quite the same as the purple rhyncho spots; ...
Jenn, those look different to me, not quite the same as the purple rhyncho spots; I'd bet that was fungal. As long as stuff like that isn't spreading, most people just pretty much live with it; otherwise you might try a good spraying with Daconil, Cleary's, or some other kind of plant disease control.
You know, I should really think twice before yapping my mouth about these experiments. I should do the experiments *first*, and then, if it turns out I'm right, I can post a big fat message,
It's like THIS!
instead of having to come back here all , "I dunno..."
So I took at look at the Rhyncho this evening, and all of the piercings have scabbed over, but there's not a single purple ring around any one of them. My cam's batteries died, or I would have posted a pic.
I want to put the plant in brighter light just to see if that will make the purple rings come (because, again, I want to be right about the purple rings) but I don't know if that will do the trick or not.
SO, as we stand now, I have absolutely no clue what causes the little purple spots and rings on Rhynco leaves, and what I thought was the cause, wasn't.
Or at least (I'm trying to MAYBE be right), conditions weren't appropriate to cause the purple rings.
I honestly do not think it's virus-related, and still stand by my guns (since all the rhynchos here behave similarly) that the spots / rings are a natural behavior of this particular plant's growth habit.
However, if anyone knows more about or can shed more light on the cause of this, I for one will be very appreciative so that I can be RIGHT the next time somebody asks this question.....
Orchid weevils are reported to be present in Hawaii, Singapore, Philippines, Thailand, Malaysia, Java, Australia, Indonesia, Japan and until recently Cook Islands. There have also been unconfirmed reports of orchid weevils in Fiji. This list may not be complete.
Orchid weevil larvae and adults feed on orchid flowers, stems, leaves and exposed roots. Recorded hosts of the pest are orchids of the genera Dendrobium, Vanda, Phalaenopsis, Renanthera, Angraecum, Saccolobium, Cymbidium, Spathoglottis, Cattleya, Coelogyne and Paphiopedilum.
Larval development and pupation takes place inside the stem. Total development from egg to adult takes about 5 months and the adults have a life span of 9 to 12 months. The adult weevil is black, up to 6mm in length with the long, curved snout typical of weevils.
The feeding damage caused by adult weevils on stems, leaves and flowers is quite obvious. Adults eat out small holes in leaves and pseudobulbs to deposit eggs. The larvae that hatch from the eggs bore into the tissues, which may then become discolored. After pupating the emerging adult leaves a hole. Damaged plants and especially flowers are not marketable. The damage caused by the larvae developing inside the orchid can or pseudobulb may not kill the plant, but bulbs often stop their growth and fail to produce flowers.
Gin, I sure hope it's not that--would mean I've got em lurking here!
Those guys and the damage they cause look positively evil!
I don't think we have them here , I hope Not ! I get enough Blems. without them . Gin
Maybe it is just the talent of the photographer but that orchid weevil looks kinda cute for a bug. It looks like it is a relative of en elephant, or rhino.
Anyways I have an update. Not sure about the spots. I really think as stated before they are superficial. They are NOT spreading.
Also this plant has an increadable amount of determination.
It now has several nice fat green roots going and..... a SPIKE!
Thanks for the help. I would likely have chucked it without you guys.
Alicia, that's great to hear!
Forum rule number (I forgot what number): No chucking of anything without consulting us'n's first.
Seriously, good news like that is always appreciated!
Uhmmm......... I doubt it, I don't think it's virus because I saw it on almost all of the rhychostylis gigantea, except those 'alba'. And in fact, my gigantea is growing happily than ever before, new leaves is always healthy and bigger than the first one. I've been growing it for more than one year now and they reward me flower every spring. IT'S COMPLETELY NORMAL. By the way, I haven't told you that rhynchostylis is a very vigorous genus, their roots are among the thickest root I've ever seen, it's quite a few but the root will branch itself; that's why a lot of people cut MOST of their root just for convenience in transporting and repotting, and their root will branch almost immediately after repot, and cling to the media heartily. I think it's not the seller's fault.
Don't worry and good luck
I just bought a used book- Vandas Their Botany,History and Culture by Martin R. Motes....there is a picture in this book of what you describe and its called Phyllosticata capitalensis Henn...the "Thai disease"...not sure thats what you have but looks the same..check into it...treatment here says to remove affected leaves and treat with triflorine....ps the book is great