Question about mealies

[Steve Johnson]

I'm not having a mealy problem at the moment, so this is just for my general info. Are all cacti pretty much prone to mealies, or are there species that get attacked more than others? I'm asking specifically about Turbinicarpus. I recently "immunized" most of my cacti with an Imidacloprid soil soak after I saw some mealies showing up on a new Mamm, but my Turbs haven't gotten any Imidacloprid yet. Just wanted to find out whether or not this would be advisable.

Thanks!

[cactiman]

If they are near the mamm's I would suggest it. The only thing I have noticed mealies not eating are milk blooded cacti. If you don’t have that many cacti just keep a close eye on it Wait and see. Zap them all again if you see any mealies.

[Saxicola]

The only thing I have noticed mealies not eating are milk blooded cacti.

Are you talking about Euphorbias?

[iann]

I think they'll settle anywhere they find. I know mites have definite preferences, but they are far more mobile.

I'd treat everything at the same time. No point chasing mealies from one plant to another for the rest of your life. Then take care with every new plant you introduce.

[cactiman]

I had a problem with them before and they seemed to leave my Euphorbias alone. could be they just prefer the others or didn’t get to them yet.

[Saxicola]

I had a problem with them before and they seemed to leave my Euphorbias alone. could be they just prefer the others or didn’t get to them yet.

Ok, that makes sense. I just wasn't sure if you were actually referring to some sort of cactus I didn't know about or if you meant Euphorbia (which you did).

[Jefff]

I had a problem with them before and they seemed to leave my Euphorbias alone. could be they just prefer the others or didn’t get to them yet.

They probably just don't like the euphorbia sap.

[Greta!]

How much of the Imidacloprid would you generally use for potted plants in a soil soak? I am sure there are many posts answering this question, but the few pages I have read didn't mention the ratio of insecticide to water. Thanks!

[Steve Johnson]

How much of the Imidacloprid would you generally use for potted plants in a soil soak? I am sure there are many posts answering this question, but the few pages I have read didn't mention the ratio of insecticide to water. Thanks!

I started using Bayer Advanced Complete insect killer in 2011. The active ingredient is 0.72% Imidacloprid, ratio 1 tablespoon per quart of water thoroughly mixed. Here are a few guidelines for you:

1. Soil soaks are effective only when the plants are growing. That means during the Spring/Summer season at least for desert cacti (jungle cacti may be different, although I don't have any experience with them).

2. Systemics take awhile to kick in. If you have a mealy problem, you'll need to either spray (Isopropyl alcohol is generally safe and effective) or pick the little buggers off by hand with tweezers until the Imidacloprid has gotten fully into the plants' juices. Figure about a month before you see that the mealies are gone. They could actually disappear sooner, but keep your eyes peeled.

3. Treat every plant, even ones that don't show signs of a mealy presence. Your systemic will be good for the rest of the year, and it's better not to keep chasing them around first.

4. There is a legitimate environmental concern about Imidacloprid since it's associated with declines in bee populations. Therefore, I would advise against letting your soil soaks run off into your garden soil. Catch the runoff into a container under your pots, then keep it in an empty jug. Take the jug with its contents to a place that disposes hazardous materials such as paints, solvents, etc. Hazardous waste sites aren't that difficult to find, and many neighborhoods often provide collection centers for home users who are sensible enough not to dump nasty stuff in the garbage.

I don't want to scare you off of using Imidacloprid, because its effectiveness for dealing with scale insects (including armored scale and Cochineal) is the best way to put them down before you see infestations get out of hand. IMO if you're willing to go the extra step to keep the Imidacloprid from getting into the ground, I think both you and your cacti will be happy about it.

Hope this helps!

[peterb]

One point: no matter how dilute, absolutely no pesticide down the drain.

Peterb

[iann]

A malathion root soak is a possible first step for root mealies. That will kill most of them. Then you can follow up with a systemic to handle survivors and newly hatched eggs over the next few months.

Imidacloprid is labelled to be used as a soil drench at about 0.03mg/litre of soil (0.03ppm). That is the amount of *insecticide*, not the amount of your product. Depending on the product you'll have to multiply by its dilution. And you'll need to know how big your pots are Better yet, use a product that is labelled for use as a soil drench. I actually use a little more than this amount. Ideally the amount should be adjusted to the volume of the plant, not the volume of the soil, and most of my collection has a quite large volume compared to a normal leafy plant in the same size pot. Strangely, Imidacloprid granules for incorporation in soil ahead of planting are labelled for use at a far far higher rate.

If you are one of those people who've been brainwashed into thinking maths is hard, using the correct dilution for a spray and watering until it runs through the pot is approximately the right amount in well-drained soils.

Diluting "the heck" out of your poison before you flush it down the sink is not acceptable. Don't flush it, full stop. Water it on other plants in your collection or spray it on something, perhaps a shrub with scale. Same for the container. It should be disposed of at a suitable facility, or at the very least you should rinse it out thoroughly (use the rinse on plants, don't flush it) before you dispose.

[Steve Johnson]

One point: no matter how dilute, absolutely no pesticide down the drain.

Peterb

Okay, peterb and Ian -- I've been properly chastised about what you both said in my post to Greta last night. I edited out the offending comment, so from here on out any reference I make to using Imidacloprid will include a specific recommendation on capturing the runoff for disposal at home hazardous materials centers.