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I need to make some mealies dissapear. What is the "end them for good" solution?
I've been nearly in tears over mealies this summer. I had a minor infestation that spread like wild fire through my crates in the moving truck and before I could get a growing area put together. There's a limit to what I can do with cats who like to "help", but I'm slowly winning with a combination of neem oil and Schultz Houseplant and Garden Insect Killer. I've had to do a lot of repotting after picking them off the growing tips though. I've been soaking the pots in a neem oil solution and spraying with the other in aerosol form--nice because the foam gets down in the leaf axils.

I'm curious to see what everyone else has to say too. Seems like this could be coming along more quickly.
Pest Control

Products that contain imidacloprid/Merit (as does the Bayer product) are very effective against mealybug. A key point is to spray very thoroughly and spray the whole collection and any other plants you have in the home. Insects do not just populate a plant or two. Merit is systemic and will remain active for several months.
I'm surprised the BT&S is not working for you. Have you been applying it so that the roots have time to soak it up? I used to use a granular form of the same ingredient in mud mixes and nothing was better at dealing with mealies. I think the way to do it with bark type mixes is to apply a weaker solution for a few waterings instead of a one-time only application. That said, I haven' tried it on slippers so I don't know if there would be adverse effects.

A drench of Orthene seemed to keep everything but mites away for about 6 months, but the stuff is truly toxic....
Orthene... Or the bayer stuff, sure.

And a touchable collection. By that I mean a collection small enough that you can handle every plant. When I was growing in the basement, I was very successful eliminating mealies by repotting everything, and spraying every surface with orthene. Then I went back a week later and sprayed every surface (of every plant), and another spray a week or so later. That is the only way, I think. If you can't touch each plant, you are doomed to always have a few plants with bugs.

I just spend two days moving and spraying every damn plant on one bench, for the boisduval scale. But I'm doomed too, since that was just one bench of many. Of course most of the plants had no scale, but I found a few that were covered, that I wouldn't have found if I had just looked at the plants from above.
I need to try the Merit I think. I've used some of the toughest stuff ever made that was banned years ago and it still didn't kill all of them. God help me if I now have Chlordane resistant mealies...

Cheap Airsoft Pellet Gun
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I purchased a couple of non-slipper orchids from a vendor, and so far, they are the only plants visibly infested. I realize many of my other plants may now be getting them. They have really become a problem in the last two weeks since my greenhouse temps have been a little higher.

I use the Bayer advanced spray, but it doesn't seem to work on the eggs I guess. I will try spraying more regularly and more carefully and see if I can finish them off.
Do I need to repot since I grow in S/H? Or would a good top spray of the media take care of the problem?
well, if spraying for 3 weeks doesn't work, consider a drench.

also as a note, if those two plants are sympodials with old growths, or have anything like woody stems, it's worth going over those areas with a contact killer like alcohol. Plant parts that aren't actively growing don't take up water as much, and as a consequence the systemic isn't carried efficiently to those areas....

As a corollary, if they are leafy things that are growing, really consider drenching the medium with the Bayer product. I've used the spray like that on orchids and they've been fine. If they are potted in a medium that can be left sitting in the solution for 30 mins, that's worth doing too, imo.
if you can find someone at a commercial greenhouse who's gonna use a product called talus, that wipes them out, but is not viable to use on a small scale as the water soluble packs take several gallons of water to dissolve...
there's the old spray everything with 70% isopropyl alcohol every three days for the rest of your life (or several weeks/months).
are they long tailed mealybugs or citrus mealybugs? (do you see any cottony sacks or just mealies with tails nearly as long as their bodies?)
see the following example:
click me. you'll swim faster...
I see the long tailed kind. One was so big, I could see it's legs move when I stabbed it with an exacto knife. Yuck.

I just finished pulling every plant off the shelf and giving it a rotating shower of Bayer, Paying close attention to the leaf axis and visible root zone. This is where they seem to hang out the most. I will spray again in 3 weeks or so and see if I have made any progress.

I guess it probably wouldn't help to segregate any new plants I get. I found one, on one plant about a month and a half ago. I sprayed back then and I thought the problem was gone. And now they are back in numbers.
I've been using imidacloprid and it seems to be working. When I spray the plants I give the leaves a little wiggle to work the stuff down into the crown where I've found them hiding. It seems to have knocked them back but I'll remain ever vigilant.
if it's a systemic, then it should spread throughout the plant. if the pesticide has been overused, you may have to deal with resistance and change to a different pesticide which has a different active ingredient and mode of action...
Right on with the chop sticks and soy sauce, Marco! Once you melt their fluffy stuff with isopropyl alcohol, they bear a striking resemblance to smelt roe… Mmm, colorful sushi garnish...

(Goes to throw up after thinking of consuming mealy bugs for long enough to have realized and typed that.)
streetmorrisart said:
Right on with the chop sticks and soy sauce, Marco! Once you melt their fluffy stuff with isopropyl alcohol, they bear a striking resemblance to smelt roe… Mmm, colorful sushi garnish...

(Goes to throw up after thinking of consuming mealy bugs for long enough to have realized and typed that.)

roe...mmmm yummy :) they turn into cooked tiny little lobsters without claws after a nice alcohol rub

Horrible odor, but it's not really all that toxic, especially compared to other organophosphates. You will want to stay out of the greenhouse for a day or so, though.

I'm a lover of Enstar II. Not cheap by any means but you only use 5ml per gallon of water. You also only need to use it twice. Just spray heavily and you'll kill those little buggers. Also, it's my understand that seeing it doesn't actually kill the bugs but stops them from having little ones, that it can be used over and over without rotation. Try it, you'll love it!!!!