I have a big problem with mealybugs on some of my tropicals. I've tried already the alcohol wiping, even sprayed them with neem oil and some insecticide afterwards, but they keep coming back and I'm afraid they'll kill my plants. I'd buy some Orthene but currently all my plants are in my living room over winter. How safe is to use Orthene (acephate) with us in the house? Would Imidacloprid be safer for us but still effective against mealybugs?
Any input is highly appreciated.
Thank you.

Just get some diatomaceous earth .. totally inorganic. You use it with a duster. If you get food grade DE then it's totally safe around pets and kids.

I really like DE for indoor use as well. Not only is it 'inorganic' but it is an inert substance that kills the bugs mechanically, not by chemically poisoning them. Don't use it outdoors, except maybe for slugs and snails (on the ground) as it will also kill beneficial insects like bees and ladybugs. Also wear a mask if you use more than a little big, as it can irritate your nasal passages - makes me sneeze! I buy the garden grade, although not as 'pure' as food grade DE, it is still very safe.

Here's a (ridiculously long) link that explains it: http://organicgardening.about....

Thank you, Anne. I was thinking to use a systemic insecticide because I've been trying all kind of stuff and poor plants are looking worse and worse with the nasty mealybugs coming back and keeping sucking on them while I'm trying this and that. I just want to use something extremely sure to get rid of them, something systemic. Maybe pellets would work better than spray?

I'd like to try beneficial nematodes too. Anybody tried those?

Thanks Elaine, I think we were writing at the same time.

So DE could be in the indoor air after applying it... with highly allergic persons around, I'm afraid to use it. How long does it take for it to settle on the plants?

It settles right away, I was using it outside in my screened pool cage, on my orchids when a puff of wind blew it into my face.

I use it indoors, under cupboards and in crannys for ants and roaches here. Never had a problem with breathing it indoors. But if you're worried, maybe put all the plants in the bathroom with the vent fan running, and dust them all in there, then wait a few minutes to make sure the stuff isn't flying around. It's not allergenic, just an 'irritant'. In fact it's so benign, people take it as a dietary supplement.

Systemics have another drawback besides their latent toxicity. The bugs get resistant to them quite quickly. Just like people using antibiotics too often, if any bugs survive the first treatment then they reproduce and the young are resistant to the insecticide.

Thanks for the detailed explanation, Elaine. One more question: what could I use to stop them from getting out of the eggs in the soil? Would DE do that too? Or how often to reapply it in order to catch the newborn mealybugs, freshly coming out after the others died under DE?

And happy new year!!

It doesn't dissolve or lose its effectiveness, really. Eventually it will wash off the plant and down into the soil, but I would think one application should take care of the next generation nicely as well.

Mealybugs are 'crawlers' when they're younger which makes them even more susceptible to the abrasive action of the DE. Be sure to dust the lower stems of the plants, as well as the soil surface, and leaf axils.

I am suffering with you, btw, just discovered a plague of mealies on one of my orchids, so the DE is in use here today, too.

Does it take long for DE to kill the culprits?

Sorry to hear about your orchid. Please keep me updated on how you used DE to get rid of the mealybugs.

Thank you again.

On orchids they hide in the leaf axils so I just puff a tiny bit into all the crannies, and any stems or roots that are exposed. You know how orchids like to show their 'legs' off.

No it doesn't take long at all. Any movement by the bugs exposes them to the sharp material and they dehydrate very fast after they are wounded.

I would not use Orthene inside. I would take old coffee grounds and BTW than again and again until the mixture is real dark and use that as a direct contact spray. On small plants, the grounds mixed in the soil will systemically kill, but it only lasts about 4 to 5 months and then the alkaloids in the coffee seem to neutralize. Tom

Very interesting. I knew about the coffee grounds but we don't drink coffee on a regular basis so it's difficult to get them used.
Thank you much, Tom.

sfrangu said:Very interesting. I knew about the coffee grounds but we don't drink coffee on a regular basis so it's difficult to get them used.
Thank you much, Tom.

If you have a Starbucks anywhere close, they give them away for free. I pick them up all the time without using to purchase anything.

Got a whole big bag of coffee grounds, thanks for the idea! Now how to use them? Just sprinkle some on top of the soil, then water? Or mix some of the grounds with the top soil?

I normally use it as a direct contact spray. Even though this was an article for cycads, the barrel in the article can be used to kill all kinds of scales, mealy bugs, aphids, white flies and spider mites. I use it all kinds of ways, but this will get you started. Look at the bottom article on this page
http://cycadjungle.8m.com/cyca...

If you don't need this much spray, you can use a panty hose and a 5 gallon bucket. I use it in the soil to systemically kill aphids on my hot pepper plants.

Yeah, I don't have that many plants, so I will make a smaller quantity. Thank you so much!

Just before starting this, do you have any advice regarding the concentration of the coffee re-brew? And are you using all of it, including the grounds on the bottom?
Thanks again so much.

The silver bags weigh 6 to 7 pounds and it makes 55 gallons. 3/4 lb would do a 5 gallon bucket full. Let it step until the liquid is real dark. For me, it takes about 10 days just sitting in the sun. If you swished the grounds up an down in the water each day, it might do it faster.

If it's for just a few plants, why not just brew up a pot of strong coffee. Would only take 10 minutes, instead of 10 days (plus time to cool off) and if anything would be more potent than the brew from used grounds.

Those mealybugs will be off to the races if you wait another 10 days on treating them, jmho.