The Acephate will be no better at controlling your problem then was the imidacloprid. When Aphids and Mealy Bugs are problems on plants then there are problems with the soil that need to be corrected because the plants growing there are not good, and healthy. Until the soil problems are corrected a much less expensive and more environmentally friendly means of control is simply to knock the wee buggers off the plants with a sharp water spray.

Many of the universities Integrated Pest Management web sites will tell you that a simple water spray, or maybe if necessary a soapy water spray is about the best method of control for either Aphids or Mealy Bugs.
Plants growing in a good healthy soil are less likely to be bothered by any insect pest. If you have a lot of insect pest problems you do not have a good healthy soil.

I don't think a mealy bug would be dislodged by a spray of water. Their waxy fuzzy coating makes it just run off their little backs. They're a scale insect as well, and they are not easily dislodged by anything.

Healthy plants can withstand insect attacks better than puny ones, and I've even read about trees under stress emitting signals insects can pick up and use to target.......but any plant can be a target regardless of soil.

A greenhouse full of beautiful, healthy plants can become infected easily, for example if you don't really look at your plants and scout out infected ones quickly. An aphid's reproductive cycle can go into fast forward in that type of environment and you can be overrun with them in less than three weeks.

How many plants are you talking about and in what environment? If you have only a few, you can dab the mealybugs with alcohol on a Q-tip and wipe them off. Aphids are soft-bodied and a gentle hort soap if properly applied should work. If you have just a few plants, you can wash the leaves with a soapy cotton ball, gently rinse them with a mister and get a handle on it. If you make it a habit to really inspect your potted plants regularly, it's easy to spot the problem before it reaches an epidemic.

You do not need to 'clean' up your soil with a drench for aphids or mealybugs. Their entire life cycle is on the exposed part of the plant. You must read the label on all chemicals and use those chemicals in accordance with the label. I think you will find acephate is a foliar spray, not a soil drench. Like I said.......the ants are there because both aphids and mealybugs produce honeydew, and the ants eat it. If you get rid of the aphids and mealybugs, you won't have the ants.

As Calliope said, Kimmsr is off base with the soil statement suggesting pest infestations mean you have poor soil and that correcting the soil is the fix. A good quality soil can not, and will not, deter bugs. Nor will simply having healthy plants, as they only tend to better withstand the insects, but are still damaged. Correcting the soil does not solve this problem by a long shot. Also, the water sprays are not always a reasonable fix or solution as it's time consuming, you'll get soaked, and if you have a large amount of plants it can be very tedious.

Also, while some studies may suggest using the water spray as the best chemical-free approach for some pests, there are zero studies indicating that it is more effective than insecticidal sprays or drenches, especially the systemics.

To top it off, most green methods don't address the nasty viruses and diseases that these suckers spread. You can't wash those off with water! :(

Boyd, I am not sure what your problem is but in the 11 years since this was originally posted I have posted numerous articles, from people with much more education than I have, that support that plants grown in a healthy soil are better able to withstand insect pests. Apparently you also missed what Calliope wrote, "Healthy plants can withstand insect attacks better than puny ones, and I've even read about trees under stress emitting signals insects can pick up and use to target.......but any plant can be a target regardless of soil."

Let's make it clear....healthy, sturdy plants can tolerate a pest infestation with more success and recover more reliably than a plant that is languishing. But container plants are always at risk as they are without the natural environmental resources that enable in-ground plants to do okay under attack.

Plant pests target vulnerable plants. That means stressed plants as well as those that are their favored species. A gardenia, for example, will always be at risk for whitefly.

There are many kinds of plants that I won't bring into my healthy yardscape as I know that they will be a natural attractant for specific pests, no matter what you do.

There are root mealies and aphids, sorry to say. They are different species than the familiar above ground pests. I would not be confident about using chemical drenches for these persistent insects.

Changing the soil might not make a difference at all unless you are able to remove all of the root clinging pests and their eggs/nymphs.

I'm a no strong pesticide person....my choice would be to toss any plant in which I found an infestation of root mealies or aphids.

kimmq I have no problem. I agree with rhizo_1 and calliope. I was just making a point that you were over simplifying things, not to mention hk77's original question was specifically about systemics. There are legitimate cases for use of such control, and while being as green as possible is important, it is not always feasible. And loss of crops and high populations of destructive pests can have their own negative impacts on the ecosystem, especially to bees. Balance is needed.