Orchid Culture - Questions & Answers from This Month
by Sue Bottom, from the St. Augustine Orchid Society Newsletter.
Email us with any orchid question. If we can't answer it, we'll find someone who can! Send photographs too!
Phal Leaf Detached from Stem
Q. I was away for the weekend, and upon my return found a very sad white Phal. She had 2 very long leaves. As I was taking the pics, one just detached seemingly from the crown. Help!
A. That looks like Collar Rot, also known as Southern Blight, one of the devastating stem rots. You can see the fungal bodies on the close up of the stem. Scroll down the SAOS website Disease page
to the Collar Rot section to read about it.
The plant is probably beyond saving.
Your only possible hope, and a slim one, is to drench the pot with some fresh hydrogen peroxide (unless you have something like Pageant) and then keep the plant on the dry side and see if a basal keiki appears. However, the tissue from which the basal keiki would grow is what is infected with the fungus, so if it were my plant, I would discard it and remove the source of inoculum from the growing area.
New Growth at Top of Pseudobulb on Miltassia
Phal Leaf Detached from Stem
Q. This Mtssa. Chas. Marden Fitch looked like it was going to be a spike, but instead of flowers it looks like a new growth. The top of the pseudobulb also looks like it is sprouting another new growth. Any ideas?
A. I have had oncidium alliance plants form keikis from the top of the pseudobulb on some occasions, but don't believe I've ever seen one form at the end of the flower spike like yours has and like often happens with Phalaenopsis orchids. It sounds like a teenager hopped up on hormones!
Leaf Damage on Dendrobium
Q. Does the mini-dendrobium have thrip effects on it? Do I remove the infected stalks with deformed leaves and treat the rest of the plant? There are new leaves on the plant.
A. The dendrobium looks like it has mite damage, not thrips, although it is hard to tell without seeing a close up of the upper and lower leaves. The new leaves look like they are being affected by mites too, so I would say the mites are still active. They seem to affect dendrobiums and thin leaved orchids much more than they do the thick leaved orchids like cattleyas. They also thrive in dry environments, so many indoor growers have to learn how to cope with them. You first have to kill the mites on this and possibly other plants. For starters, take them to the kitchen sink and spray them with a mixture of isopropyl alcohol and dish soap, lather 'em up and wash the leaves. Then get a spray bottle of isopropyl alcohol and spray the leaf surfaces top and bottom. Make it a weekly event, perhaps part of your watering routine. You might consider treating with one of the three in one insect, disease and mite control products containing the active ingredients Imidacloprid, Tau-Fluvalinate and Tebuconazole. (Feb-20)