Mealybug!

[T.bridgesii]

Just spotted a 3mm-ish mealybug on one of my new cacti. Just the one, but I’m assuming there are probably more hiding if there is one. I thought I did a decent job of inspecting these guys when I received them, but it looks like I wasn’t quite good enough.

Having never had to deal with this particular pest before, I have a few questions:

1. How mobile are these things? What are the chances they have spread to other plants in a few weeks? How far can they travel? I’ve treated all plants (as below) within two metres of where I saw the mealybug, but do I need to treat the other (further away) plants in the same room?

2. I’ve doused them with Bug Clear Ultra (systemic insecticide that lists mealybugs on the label - active ingredient is acetamiprid, which seems to be the only systemic that isn’t banned here) making sure to saturate the growing media around each plant too so they will be sure to absorb some. Will repeat in 14 days as per instructions. Is this going to be sufficient? (I removed and squashed the live bug, but am worried about others and/or eggs. I have lots of houseplants, and really don’t have the time or energy to deal with a protracted bug infestation, so I want to “nuke them from space” now before it gets to that point.)

3. I’ve seen horror photos of root mealybugs. Is this a separate species, or do the same ones that attack roots also appear on the surface (this one was hanging out in plain sight on top of a cactus)? Just wondering if I need to un-pot them to treat more aggressively. I’d hate to do that now, as they’ve just come out of dormancy and received their first spring watering a week ago, and I’d expect are just starting to grow new roots (roots were trimmed and they were sent to me bare root).

I un-potted a couple succulents that were nearby, and didn’t see any mealies on the roots (though it becomes difficult to tell when perlite looks so similar...)

[greenknight]

Root mealybugs are a separate genus.

Mealies crawl only a short distance, treating everything within 2 meters is probably sufficient - but remain watchful.

For more details: https://content.ces.ncsu.edu/mealybugs

[T.bridgesii]

Root mealybugs are a separate genus.

Mealies crawl only a short distance, treating everything within 2 meters is probably sufficient - but remain watchful.

For more details: https://content.ces.ncsu.edu/mealybugs

Thanks. I absolutely will be watching closely now.

I’m glad I happened to glance over at that cactus exactly when I did, because the bug wasn’t there five minutes before, and probably would have hidden again. Guessing it must have been well camouflaged in the wool of the cactus (Lophophora).

The only plants on the same shelf that I didn’t treat with insecticide are carnivorous ones (because I’m not sure if it is safe to use insecticide on them)...hopefully mealybugs don’t like them.

[keith]

Is this a separate species, or do the same ones that attack roots also appear on the surface "

Different and root mealies are especially bad because you cant see them until its too late. 30 years ago I had my duel with root mealies.

Imidacloprid / Merit saved them .

[greenknight]

Root mealies feed only on the roots. They belong to their own genus - there are several species of root mealies, but the differences between them are microscopic.

[jerrytheplater]

I had root mealybugs in my dormant Rebutia and Sulcorebutia and other cacti. Pretty bad case. Maybe December in the 1990's-a long way till Spring. I de-potted. Washed all potting mix from roots. Washed plants in 2% Ivory Liquid soap (Edit: 5 Tbs plus 1/4 tsp per gallon water, or 20 ml per liter) followed by a drench in a Malathion solution. I dried on newspaper and stored them till spring bare root when I potted them back up. This allowed me to observe for re-infestation. They all did fine. I should say the bare root plants were in a very cold (45F) room before we needed it for kids.

[jerrytheplater]

If anyone is using the soap dilution I gave above, I just corrected it. Please note. I suppose you could easily get by with just 5 Tablespoons and forget the 1/4 teaspoon.

[T.bridgesii]

Different and root mealies are especially bad because you cant see them until its too late. 30 years ago I had my duel with root mealies.

Imidacloprid / Merit saved them .

Good to know. Imidacloprid is banned here, unfortunately.