Follow the directions on the product. Norma

As Norma intimated, follow the directions as per ornamental plant use, and ensure that the product doesn't kill Crassulaceae (I forget which one does).

Thank you all for the replies.

Brad,
Thanks for responding. I am planning to use that product as a fungicide.
Just a few question.
Do you apply it as a spray and in what frequency?
Do you alternate it with any fungicide?
Do you start applying in fall for the winter protection?

I was thinking of using both ortho and bayer because of their distinct active ingredients.

As far as the Bayer for trees and shrubs, I'm still looking for the 12 mo protection without fertilizer, but haven't had any luck.
I've read that imidacloprid could have a negative effect on spider mites (causing their population to increase).
But, I assume if imidacloprid is used in a soil drench application, there won't be a problem with spider mites. Am I correct? Thx, -j

I use the Disease Control product as a spray as needed. Most of the fungal problems I have crop up in the winter while its wet. Frequent spraying (2-3 weeks) helps control the disfiguring black spots. I probably won't be using it again until winter.

I noticed that there was none of the old B T&S at OSH recently. There were several new formulations for trees and shrubs, and lawns, some containing different amount of fertilizers. It looks like Bayer Tree and Shrub Landscape formula is the way to go. It is twice as concentrated as before (now 2.94% imidacloprid), so use 1/2 ounce, 1 tablespoon per gallon.

Another good product, although relatively expensive to use, is Bayer 3-in-1 Insect, Disease, and Mite control. Use as directed on the label. Most of the time, I don't need the 3-way treatment, and it is cheaper to use the single ingredient products

The problem with spider mites is that imidacloprid gets rid of their predators. A spray or soil-drench would have the same effect. Some folks don't like imidacloprid because of its potential toxicity to honeybees.

No presticide/fungicide/miticide is perfect, nor should any one approach be used all the time. One of the new 'natural' products that Bayer is selling (Natria) is almost pure Canola oil. It's probably cheaper to get that at the supermarket ;)

Thanks Brad.

I was wondering how a soil drench application would harm the beneficial predators unless they're sucking pests. thx, -j

I'm glad I read this thread before I treated my collection because I wasn't aware the formula changed and I would have used the new one.

I found almost a full gallon of the old stuff in my garage when I was looking for something else today so that made me happy. Then I was at a small local nursery and they still have the old formula for $34 for the 32 oz bottle.

I also found this product online; Dominion Tree & Shrub. it has the same amount of imidacloprid with no fertilizer, but the bottle looks very strange; like you have to premix it. And Bonide systemic Houseplant insect control also has imidacloprid in it at a much lower rate. Not sure how good this would be for cacti.

I know the Bayer product works great on trees, we have the only healthy birch trees on the street.

So thanks again!