CactiGuide.com

Hi everyone,

I have spent a lot of time into my fight with mealy bugs on the stems and roots of my cactus. Fighting them with alcohol and dish detergent has been a losing battle. I have about 60 indoor potted cactus that need to be treated and it seems that watering with a systemic is my only hope. (I should have quarantined my new plants and will in the future, as my whole collection was impacted quickly.) The problem is that it's getting cold here and I need something I can safely apply indoors. I am also battling chronic illness and very sensitive to chemicals. Can anyone recommend a nontoxic (to humans) systemic insecticide to decimate the mealy bugs?

Take the plants out of the pots and use a paint brush and a cocktail stick clean the roots of mealies pocking the adults and cleaning off the white waxy fur they leave behind. Treat with alcohol again then let the roots dry in a dark/shady spot for say a week then repot. You might want to try a leaner mix soil with less organics and more mineral ingredients, the mealies seem to prefer more organic soil mixes. You can then avoid any toxic stuff to kill them, you may want to check all plants and isolate the infected away from the clear plants.

Thanks so much for the advice. This is my first time dealing with mealy bugs and it's surprising how tenacious those creatures can be. I will do as you suggested and put the plants in a dark room for about a week before repotting this time.
For soil, I use a grit mix of clays, pumice and turface. I hope to avoid tossing out the potting mix if at all possible, as it is more costly than most of my plants. Is it possible to kill off all the mealy bugs/eggs in the soil by baking the grit mix in an oven?

Thanks again for your feedback. I truly appreciate the helpful advice.

sunlover7 wrote:Is it possible to kill off all the mealy bugs/eggs in the soil by baking the grit mix in an oven?

Baking should do the job. Off the top of my head, I'd say 175 for 1/2 hour, although 1 hour may be better.

Excellent! Thanks, Steve! I'm becoming more optimistic about the prospect of eradicating these pests.

Depending on what plants you have mealy bugs on they can be almost impossible to get rid of even with nasty systematic insecticide, which i will use about 3 times a year on most of my plants. They love asclepiads more than anything from my experience, i will scrape and pick and kill as many as i can see on a single plant then blast it with a hose/faucet (if its not going to harm the plant or roots) and then soak it in pesticide for a little while. I have tried a couple natural systematic brands with a little bit of success: Sierra Natural Science and Bonide, i think i had better success with Sierra Natural Science. Toss out any pots or soil that you get an infected plant in or if you have to you can try microwaving the whole thing, 3 minutes dry and 3 minutes wet (water) then try to repot. FYI keeping plants indoors makes them more susceptible to bugs/pests, also if the plant is not in a growing spurt it might not soak up the insecticide like you would want it to, thats why its best to soak your plants pots during growing seasons and just before winter cause they are more susceptible to getting attacked when they are more dormant.

best of luck to you, it takes practice to get mealy bugs under control !

What I found very good for root mealies is Provado vine weevil killer concentrate.It has a different ingredient in it than the other stuff.With it being concentrate and you having to mix it yourself you can add a little bit extra too to make it a little stronger.As already said it does take practice,I treat my plants during the summer growing period and before the winter arrives and of course at any other time if i see any.New plants must be thouroughly checked and quarantined and I personaly treat new plants once they have settled into their new soil etc.

Sylv.

I managed to eradicate root mealybugs by plunging the plants, in their pots, into a bucket of soap solution, until they were saturated (the pot stops bubbling). Has to be done during the growing season, obviously. Nothing fancy, I use Fels Naphtha laundry soap, dirt cheap. Would be a pain to do this with a large collection, though, especially since repeat treatments are advisable.

greenknight wrote:I managed to eradicate root mealybugs by plunging the plants, in their pots, into a bucket of soap solution, until they were saturated (the pot stops bubbling). Has to be done during the growing season, obviously. Nothing fancy, I use Fels Naphtha laundry soap, dirt cheap. Would be a pain to do this with a large collection, though, especially since repeat treatments are advisable.

I can vouch for this method too! I soaked the roots of the plants for about 15 minutes and it took care of most of the root mealy bugs. To remove the rest of them I mixed up some more concentrated soap solution and used a spray bottle to apply it to the plant. You need repeat applications as Spence said, but it does work quite well, and as a bonus it seems to take care of red spider mites!

Deleted

I started an experiment watering with diluted coffee. So far I don't see any mealybugs...

The soap i use, Fels Naptha, is an old-fashioned laundry soap (no naptha in it anymore, they took that out years ago). It's a yellow soap cake, you shave some off, use a tablespoon of the shavings per gallon of solution, dissolve it in a little hot water before you add the rest of the water. You want plain soap without additives. I don't know what's available in your country.

You soak the pots long enough to saturate them - when they stop bubbling they're completely soaked. Then you take them out and let them drain.

Merit 75 WP works well on root mealie bugs, OK on stem mealies. it doesn't smell like the stuff you buy at Home depot type stores.

Probably have to buy online and keep away from bees.