mealybug treatment questions

[lobotomizedgoat]

Discovered mealybugs on three of my paphs today. I wiped off what I could with isopropyl but many were hiding out of reach in the crown and crevices between the leaves. I think I got some of those by dripping some alcohol in then rinsed them thoroughly, but I know there are still some hiding because they keep popping out here and there.

My goal is to find an imidacloprid product tomorrow, but I'm curious what other pesticides are effective (and safe for indoor use) in case I cannot find the good stuff where I live.

I'm also curious which treatments should be kept off the roots. I've seen various solutions of horticultural oils, soap, and alcohol mentioned but I don't have a good sense of what is OK to use on both foliage and media.

Lastly, while I only found three affected plants I'm guessing it's best to apply treatment to all the plants in the grow area just in case?

[Ray]

Go to your local Lowes or Home Depot and pick up a bottle of BioAdvanced 3-in-1 Insect, Disease, & Mite control.

At one time it contained imidacloprid, tau-fluvalinate, and tebuconazol, but recently I have seen the same product with only the latter two. Either way, it works well on mealy bugs, and is safe for orchids.

I have a pyracantha in a remote corner of my yard that they love. One time it go so bad that it looked like I’d sprayed it with the white “flocking” stuff used to simulate snow.

No matter which product you use, wet all exposed surfaces of the plants and drench the media, as mealies can populate roots, too. Treat 3 times at 1-week intervals.

[Dimples]

I used Bonide annual tree and shrub when I found mealybugs on a few of my houseplants. I treated the whole collection (40+ plants) even though I only saw them on some of the plants. I treated my phals along with everything else. I couldn’t find anything else locally that had imidacloprid or another active ingredient that was effective for MBs.

The T&S has a stronger concentration of imidacloprid (the only active chemical in it) than the 3-in-1 or other imid. products aimed at houseplants. I used the label rate for root drench of outdoor ornamentals and treated twice with a one month interval. Based on the product label and the available research on imidacloprid, the second treatment was likely unnecessary since imidacloprid retention in organic matter/potting soil should be quite high, so plants can take it up constantly over time, but two treatments ensured the MBs were gone.

Orchids planted in bark/porous media don’t have the same quantity of imidacloprid available for root uptake following a drench (bark holds significantly less liquid than potting soil), so repeat applications aren’t a bad call.

[estación seca]

Mealy bugs crawl away and lay eggs far from your plants. Eggs have been demonstrated to remain viable for 2 years. You need to be always vigilant.

[camille1585]

I would also go over your growing area with a fine tooth comb and scrub everything down. I've found mealies under the saucers the plants sit in, under the L shaped rim of the shelves, in my box of supplies under the shelves, under cushions on a nearby chair, and I've found them in my sewing box stored a couple meters away from the orchids. I had a rolled up zipper in there that was absolutely infested with mealies!

You probably caught it early enough, but they can get EVERYWHERE and cause new outbreaks months down the road.

[Roberta]

You can increase the reach of the alcohol with a sprayer. Just put it directly in the alcohol bottle and you will be able to get it into the crevices. Then as others have advised, follow up with a "real" pesticide and repeat... and be vigilant,

[lobotomizedgoat]

Thanks for all the advice!

I spent a good part of today cleaning and inspecting around my little grow area. Thankfully, I didn't see any sign of more. I also picked up the 3-in-1 and will be going to war with it tomorrow (indeed, it's just the tau-fluvalinate and tebuconazol).

[estación seca]

I should mention soaking. I don't use pesticides around my house. I have next to no mealybugs nor scale after several years of regular inspection and rapid treatment. When I find a plant with pests I first spray it with alcohol or soap solution. Then I scrub off pests I can see at the sink. Then I submerge it completely, plant and pot, in a pitcher or bucket of soap solution, for 8-12 hours. This drowns bugs and eggs with minimal harm to the plant. I wouldn't submerge a heavily infested plant; I found out soap enters the many piercings and damages the plant. I invert the plant so the medium doesn't float out. This also works with cacti and succulents if you do it during their growing season. Cacti may have a severe root mealy bug infestation. The only sign is tiny egg cases on spines.

Plants too large to soak I spray with Neem or horticultural oil after the soap or alcohol.

[Dimples]

Yes, don't spray pesticides in your house.
I took all of my plants outside to a paved area and applied the imidacloprid drench to the pots carefully to avoid runoff. I also sprayed the foliage with neem and waited until everything was dry before bringing them back inside.

[lobotomizedgoat]

I drenched the plants and media in the 3-in-1 with a spray bottle then brought them back inside to a quarantine zone once dry. However, I've found some live bugs on them since. Is that a sign that I missed some areas in my application or might the the pesticide just be ineffective? (it's the imidacloprid-free formulation)

Estación, what concentration of soap and neem do you use? I may try that at some point, too. Luckily, these are small plants so it will be easy to submerge them.