Needing help/advice - Orchid Board

OrchidDelight · #1 05-04-2017, 07:19 PM

I'm new to the orchid world and having an issue with one of my phals. I purchased it from a local nursery and while in the quarantine stage I noticed that it had mealy bugs. I unpotted the orchid removed all mealy bugs in sight and covered the orchid in alcohol. I repoted it in new medium and just kept an eye on it.

About two days later I noticed the bottom two leaves were turning yellow and wilting. When inspecting it I saw what I thought was more mealy bug cotton looking substance near the crown. But now I'm thinking it may have been fungus.

I've unpotted the orchid again removed the dead leaves and noticed half my roots have died. I've removed a lot of the root that I know are dead. The ones left still have dark spots on some.

I don't know what I'm dealing with should I cut any root the has dark spots on it? I've sprayed it in hydrogen peroxide. But I'm lost what to do next. I don't know if it's fungus, crown rot or root rot ?!?!?

I've attached pictures of my plant and would welcome any advice you can give. Thank you

estación seca · #2 05-04-2017, 09:58 PM

Welcome to the Orchid Board!

The photos show a plant that should recover with decent care - if you control the mealy bugs. Alcohol will not be enough. It does not kill their eggs. They will be back.

I would try to return it for a refund. Vendors should not sell plants infested with mealy bugs.

If you keep it, here are some good threads to learn about growing Phalaenopsis:

The Phal abuse ends here.

Using skewers to determine when to water

Arizona Jeanie · #3 05-06-2017, 02:28 PM

I realize that there are varying opinions about using chemicals on plants, so not everyone would agree with this but here's what I think. Both alcohol and peroxide are toxic to living cells, and can damage the plant while not wiping out the mealy bugs. Why not use an insecticide that will kill all the bugs and not hurt the plant? With one infected indoor plant, it would not involve a wholesale chemical dousing of your (and our) environment. Imidacloprid is very effective against mealy bugs, and is available in a number of products. It is toxic to honeybees, so I wouldn't use it outdoors, but used carefully, according to label directions, it is safe and effective.
My outdoor roses have aphids and thrips but also ladybugs and lacewings--I have even seen hummingbirds picking the aphids off the buds. I wouldn't use any chemical control on those, but I think I would use a careful dose of imidacloprid in your situation, and skip the peroxide and alcohol.

jkofferdahl · #4 05-06-2017, 03:58 PM

Peroxide will absolutely cause damage to orchids, and especially the roots. I don't agree that the use of rubbing alcohol is damaging, however. It's quite efficient for killing scale and mealy bugs, and in over 40 years of growing I've yet to see any trace of damage caused by it. Still, the use of a systemic insecticide is probably the second best option. The BEST option is, as ES suggested, returning the plant to the seller and asking them why they are selling infected plants. And let us know the seller, too, so we can avoid them.

Ray · #5 05-06-2017, 04:47 PM

The only time I have seen 70% isopropyl alcohol damage plants was when it was sprayed on flower buds a couple time S a day for several days in a row.... it desiccated them.

PaphMadMan · #6 05-06-2017, 05:23 PM

Rubbing alcohol includes a range of formulations. In the US it is most often 70% isopropyl alcohol in water, but there are ethanol based products, higher percentages and a variety of additives that may be present. In other parts of the world it can mean a wider variety of things. How much potential there is for damaging plants depends on the formulation and how it is used, but any of them can kill roots of Paphs and can do some damage to leaves of jewel orchids, so it isn't completely safe in all cases.

I agree the most effective product would be a systemic insecticide, and using rubbing alcohol alone against mealy bugs with a collection of more than a few plants is essentially a full time job with absolute life-long job security - at least until the mealys win and all the plants die. I also understand why anyone could be reluctant to use pesticides in their living space especially with children or pets. There is a reasonable alternative.

Insecticidal soap is very effective against the immature crawler stage of mealy bugs and of at least some use against exposed adults. In terms of safety for people and pets it is soap - just soap - and nothing more. It is even accepted for organic farming. The particular kind of soap just happens to be death to soft bodied insects. Used as directed it is safe for plants. It might take twice a week applications for 2 months to approach complete control of mealy bugs, but it is far less tedious than a cotton swab with rubbing alcohol, and safer as well. It is not the same as dishwashing detergent or any cleaning product, so make sure you get the real thing.

orchidsarefun · #7 05-06-2017, 05:39 PM

I read somewhere on OB that diatomaceous earth, mixed with Dr Bonners and water is effective. I can kick myself for not following up. Does anyone know/ think this would be effective?

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jkofferdahl · #8 05-07-2017, 12:26 AM

Quote:

Originally Posted by orchidsarefun

I read somewhere on OB that diatomaceous earth, mixed with Dr Bonners and water is effective. I can kick myself for not following up. Does anyone know/ think this would be effective?

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I'm a strong adherent of the use of diatomaceous earth, and do so regularly. I'm not sure about mixing it with Dr Bronners, and certainly wouldn't mix it with water. And as a spray, I would expect the DE to clump a bit and clog. DE's great for killing many insects - ants, flies, cockroaches and associated house pests - and with orchids it's a great preventative. Regular use will control what may try to infest plants. It won't stop everything - I just had to take care of scale on a Phal, even though it had a dusting of DE still on the leaves. When there's an infestation of something like scale, mealies, and other small creepy-crawlies that's already taken hold it's not the greatest. A systemic insecticide is best, and with these invaders it needs to be liberally applied. More than once, and at least a time or two after you're absolutely certain the little devils are gone. Insecticidal soap works pretty well, but will likely take more applications.