Help deciding the next step on Mealybug Control?

[jaggars]

I have 2 rescue Phals that I bought after Christmas and both have been doing really well until I noticed a weird, little bug on one of them....MEALYBUG! I treated it with alcohol and put it in quarantine. The next day I found 2 more plants that had one on them.
My question is Do I really need to repot them since I only found 3 bugs total on all the plants?? I'm kinda yay or nay on what to do. The other 16 phals have not been infected and it has been 5 days since treatment and I have not seen any more bugs.

[Ray]

Having mealies does not mandate repotting, but as there is a chance that they might have colonized the root system (unlikely, if you've only seen 3 in 5 days, but still possible), I'd soak the pot with an insecticide, just to be sure.

There is a relatively new, OMRI organic formulation out based upon spinosad, a bacterial fermentation product, that is quite effective and safe to use. It has a mild musty odor, but that's temporary.

[rbarata]

Mandatory: isolate the infested plants from the others.

[Orchid Whisperer]

Ray, spinosad is not a good fit for controlling mealies, though it is a good choice for controlling thrips, caterpillars and other chewing insects.

Spinosad is a contact and/or ingestion pesticide. Mealies are somewhat protected from contact poisons by an external waxy coating. That does not mean that mealies can't be killed by contact poisions at all, but they are less effective. Mealies (also scale insects) mostly are sucking feeders; they might ingest a little pesticide drilling into a plant, but maybe not enough to kill them. You may be able to improve contact poison efficiency by mixing spinosad with a detergent (?) as a sticking agent, but that is just a guess. There are contact poisons that do work on mealies, and many of these seem to be soap or oil-based.

Better controls for sucking insects are systemic controls which are absorbed into the plant. Imidacloprid is one choice (in several Bayer products); Orthene (acephate) is another. Both of these chemicals are readily available in big-box hardware stores, at least in the USA.

Spinosad and imidacloprid are both growth disruptors, but the mechanism is slightly different.

A good source of information on various chemical controls for insects and mites is available from the St. Augustine Orchid Society: http://staugorchidsociety.org/PDF/Pe...rchidPests.pdf This chart also includes recommended dilution rates for application.

[rbarata]

Ray, spinosad is not a good fit for controlling mealies, though it is a good choice for controlling thrips, caterpillars and other chewing insects.

I think Ray sugested it because, from jaggars' description, it seems to be, at this point, a minor degree infestation (or the beginning of a major one). As he stated previously: "Having mealies does not mandate repotting, but as there is a chance that they might have colonized the root system (unlikely, if you've only seen 3 in 5 days, but still possible), I'd soak the pot with an insecticide, just to be sure."

I also agree that systemic is the way to go. I use thiacloprid, an evolution of imidacloprid. The down side of it is to be harmful to bees and other beneficial insects.

[jaggars]

Thank you guys for the information. I did not even think about soaking the roots in a insecticide. They must have traveled back home with me from Lowe's. Both plants were in container gardens and was discounted after Christmas and the third one was sitting next to them on my shelf. I am a weak when it comes to rescuing orchids from Lowe's. :/

[rbarata]

What I usualy do when I get a new orchid, no matter where I get it, is to put it on quarantine for a month.

[wintergirl]

When I get a new orchid, I repot and get that old media right out of the house.

[rbarata]

When I get a new orchid, I repot and get that old media right out of the house.

That's a good practice that I'm too lazy to implement.

[estación seca]

A cheap rescue plant is not a bargain if it kills other more expensive plants.