Getting rid of mealybugs once and for all.

Factual Questions
1

I have an enclosed patio off my living room, and I use it as a greenhouse. It’s heated, and has a ceiling fan/light that keeps it comfortable year-round. But the place is infested with mealybugs. I have gone after them with cotton balls dipped in alcohol. In summer, I have taken plants to the driveway and hosed them down. Twice, I have bought bugs similar to ladybugs that supposed eat mealy bugs. I have used every kind of spray made. But everything I do winds up being merely a temporary measure. The one good thing is that they haven’t invaded the rest of the house. I have many hanging plants in every room, and so far the bugs have not discovered them.

The only thing I haven’t tried is freezing them. So I’m going to just lock the patio door and forget about them until spring. I’ll leave a few patio windows open a few inches, to insure that the outside weather is getting in. Of course the plants will die as well, but I’ve taken cuttings of some of the difficult-to-replace ones, cleaned them thoroughly, and will be rooting them until spring.

Any reason why this all-out-war may not work? Am I correct in thinking the mealybug eggs will die as well as the mature bugs? Am I overlooking something?

2

I had a serious mealy infestation the past two summers on my screened-in second-floor lanai. The first summer I threw out most of my infected plants, relocated the clean ones to a separate area, and sprayed the rest (my prized pineapple plant!) with neem oil once a week for a month. It worked…for a while. I had to do the neem oil thing again after a few months, and I thought winter would kill them but it didn’t. Summertime, they were back in full force so I did the neem oil treatment one last time. It takes care of mealys really well, but with my plants (mostly bromeliads) there are just too many crevices for bugs to hide. I ended up giving all my plants to a friend who planted them in her big yard. Apparently they’re flourishing, so something outdoors took care of it.
Also, some mealys (I think pre-adult males?) have wings…so beware leaving your door open for fear of infecting inside plants.

3

But wouldn’t the pre-adult males cause a minimum of damage, since they can’t reproduce? I’m not even sure whether any of the adults actually cause damage at all. Wouldn’t there be larvae hatching from the eggs, and wouldn’t they cause the damage . . . like with moths whose larvae eat wool?

What I need to verify is whether prolonged freezing temperatures kill all the stages, especially the eggs.

4

One little known contributor to infestations of mealy bugs are the ants that carry them to new hosts (much as they do with aphids); in my nursery ants must be eliminated before I can reasonably hope to control mealy bugs.

Have you tried removing the plants from the pots, washing off all the soil, and repotting? You will also need to wash the area where the pots set with alcohol, as the egg masses and overwintering adults will often find some surface to rest on outside of the soil.

Freezing temps will not kill the eggs in my experience; like many insects, the eggs are pretty cold proof.

5

Unlikely. Most animals that live in areas with freezing temperatures have some kind of way to make it through the winter, or they wouldn’t still be around. Probably the eggs can stand freezing and thawing, and you’ll be right back where you were in the spring.

6

If mealybugs are not native to the OPs area (i.e. do not infest outdoor plants), then there’s a fair chance that prolonged subfreezing winter temps will do them in. I’d nuke 'em with spray one last time before subjecting the area to winter cold.

Truly, these are rotten pests and if there’s a substantial infestation, it may not be wise even to take cuttings. Write off the entire mess and start over.

7

I’ve decided to go ahead with the freezing, since I have nothing to lose. In the spring, I’ll put a few expendable plants out there and see what happens. Oh, and I’ve never seen any mealy bugs outside, possible evidence that they don’t survive winter . . . or something may be killing them out there.

I’ve got the cuttings in a remote window, to isolate them from other plants. In a day or two they’ll be ready to start rooting.

8

Little woolly bastards! If you don’t want to use systemic insecticides (the most effective method, but nasty chemicals) then I’m with Lionne on the neem oil treatment. You’ll need to treat them regularly for quite a while, as neem works by interfering with the reproductive cycle so all the eggs in the soil have to hatch out and the adults need to be kept sterile until they die of old age.

For any stray mealy bugs you come across, squish 'em or dab with a paintbrush dipped in alcohol (vodka strength and above works well).

I’ve never had much success with biological controls, as in a closed system the predators don’t eat themselves into extinction, and unless all the mealy bugs are killed the population will bounce back.

9

I found a nasty infestation on my ficus tree - it’s 24 years old (I bought it as an 18 inch sapling in 1989) and I do not want to lose it.

I’d brought home a small potted dwarf pomegranate about 14 months ago, took that to my office for a bit as I’d been neglecting it and it needed more frequent watering, and I figured I’d be less likely to ignore it there. After a few weeks, I spotted a couple of what were almost certainly mealybugs.

Manual removal seemed to solve that problem. Maybe 3-4 bugs total, removed with a Q-tip dipped in rubbing alcohol, and I have not seen one on the plant since then - even after I brought it home.

Then a couple months ago I was walking by the ficus, and noticed that there was a substantial accumulation of dust in some of the branch joints, and looking more carefully I also spotted a heavy infestation of the mealybugs.

Now, the tree doesn’t seem to have been harmed - it’s growing well enough. But there were hundreds of leaves affected. A small enough bug doesn’t seem to damage the leaves but if you look carefully you can see a little brown spot at the base of the leaf where the bug did a little juice-sucking.

What I’m doing: a LOT of manual removal with q-tips dipped in alcohol. Several (so far) sprayings with insecticidal soap. I bought several large bags of potting soil, removed the ficus from the pot, shook off as much soil as I could, and repotted it with fresh soil dosed with a liberal sprinking of Bonide (insecticidal granules).

For good measure, I did the same with most of the rest of my houseplants, though none of them seem to be affected by mealies yet. As a side benefit, the Bonide seems to have finally gotten rid of the *&#@ fungus gnats that came home with me from a former office; I’d used biological controls (BT granules) to try to control those but that didn’t touch the problem; drying the plants to the point of killing several and damaging others was what finally got that somewhat under control and they still surfaced now and then.

And there are still some mealybugs :mad:. I need to do another round of q-tip/alcohol swabbing, and another dose of the soap spray and Bonide. To show how hard the damn things are to get rid of: I took several cuttings from the tree (those little shoots, plus a few cuttings from pruning it). I washed the cuttings thoroughly. Just yesterday I was checking the cuttings (which are rooting nicely) - and spotted a mealybug. Dammit.

10

Onslaught used in combination with Nyguard. Powerful and expensive stuff, but if used correctly it’s safe for pets and around food and will last months.

11

Yeah, I think mealys are right up there with roaches in terms of survival. If I ever get another mealy infestation, I’m tossing everything out…just can’t deal with the cycle again.
Mama, I hope your ficus makes it through! My oldest is a Dracaena from 2005 and if that ever went, I’d be quite sad.

12

Thanks!

I just did some more swabbing over the past few days, and today I spotted two leaves I’d obviously missed. Grrrrr.

Yesterday, after the swabbing session, I dumped a cup of Bonide granules into the ficus pot. The “dosing” instructions only go up to something like a half-cup for a 3-gallon pot, so I was guessing - it’s a 14-inch diameter pot which I’d estimate holds 5-6 gallons at least. The original dose (6 weeks ago) was probably a lot less than that. I hope this (plus more wiping and some insecticidal soap spray) deals with it. I’ll have to really keep up with the Bonide, and watch the other plants carefully too.

The ficus is actually not our oldest plant: We have numerous descendants of a Chinese Evergreen (aglaonema?) that belonged to Typo Knig (husband) and his roommates before we got married 30+ years ago. And before that it belonged to a fraternity. So you know those things are unkillable. But, I had one at work that was salvaged from an office lobby; they were replacing all the plants and I saved one from the trash… and it had mealybugs… and I didn’t bother getting aggressive with it, so it died (from some combination of mealybugs and neglect).

13

I lost a schlefflera that I’d had since 1973, and a few offspring. I felt like nuking the little buggers.

14

I’ve had pretty good results with Nuke’Em and Take No Prisoners. But you have to evacuate the neighborhood for at least 48 hours and wear a moon suit for several weeks afterwards.

It’s easier just to throw the infested plants out.
I thought I was joking about the above-named insecticides, but there actually is a bug killer called Nuke em. :eek: