Thank you Jim! I love experiments like that. Rose slugs were so bad one year that I resorted to systemic. Within the week they were tiny black skeletons. I'd love to have praying mantis. I wonder if they'd eat the caterpillars off the delphiniums? They're relentless.

The aphids have just been relentless on the bush. Probably could spend $8 on some spray, but no thanks to that. OK, just for the record, here's what I did with the bush: Decided to let the bush die and so stopped watering the pot. It wilted badly, needless to say. Then I felt sorry for it and watered it. Chopped the whole thing down to about 6" with 1-2 tiny leaves. Remembered someone had luck with worm castings and whiteflies, so I put about 1/2" of worm castings on top of the soil. The bush has resprouted, has a little bloom, and no sign of the aphids. Not sure what worked here--maybe the dry soil, maybe the chopping down, maybe the worm castings. But I hope it continues to do well.

This post is getting a bit old, but is is an interesting subject. I wouldn't think too much about the traces of toxic chemicals that might remain in your soil. The worst ones are typically fungicides and weed killers, they can build up in soil. Insecticides are often derivatives of plant extracts like tobacco (nicotine), and chrysanthemum (pyretrines), and nature hopefully takes care of them. However the situation, the roses will happily go organic, and if you don't have any particular problems with fungus in your area, it should be an easy transition. Good compost, composted cowmanure, seaweed meal, and stuff like plant friendly microorganisms; tricoderma (and others I can't remember their names), that can be added to soil and sprayed on the plants to help establish a healthy balance of natural microlife in the soil and around the plants. There are different kinds that can be bought in bottles, packages and boxes. If you cannot find any near you, you can take half a bucked of real good compost fill it with water,let is sit there for a wile, then strain it, and spray plants, leaves, ground and all with it. Compost and organic matter will help bring back earth worms, that bayer all in one products might have killed off.

Khalid wrote in another thread: "Then I stopped spraying even any organic matter. I gave more calcium to my roses which made the soft branches and leaves harder thus making it relatively unattractive for the pests. This reduced the affected bushes / leaves to a good extent." Agree with Khalid, folks in rainy climate lime their soil, either in late fall or early spring, depending on how many inches of rain they get. Rain is acidic at pH 5.6, as the pH drops, less calcium and potassium are available. The best lime to use is Espoma Garden Lime (sold at Walmart for $10 per 5 lb.). It has 20% calcium and 10% magnesium ... both are essential in keeping leaves thick so pests cannot invade. From the above chart, around pH 5.6 (rain water), less molybdenum, less magnesium, less calcium are available. Next nutrients that are less: phosphorus, potassium, and nitrogen. I already posted in Organic Rose my experiment that I did with 2 identical Thai basil: I lowered the pH of one with acidic cracked corn (pH 4), plus gypsum (17% sulfur) .. that Thai basil' leaves became pale, plus THINNER due to less calcium and magnesium available. Then I saw blackspots on a Thai basil for the 1st time !! The other basil I planted in my alkaline clay (pH near 8), and it's twice taller plus really thick & glossy leaves (more available nitrogen, potassium, sulfur, calcium, and magnesium). But leaves were just a bit pale due to less iron at high pH, so I gave it blood meal, has chelated iron, and leaves became dark green. I once planted a bok-choy vegetable next to my patio with a limestone base, so the soil is very alkaline, pH 8. The leaves were dark-green, but its so tough that I boiled it for one hour, and it's STILL so fibrous that my teeth can't handle, let alone some tiny pests like aphids, rose slugs, or midge. Rose slugs (sawfly larvae) are very rare in my alkaline clay, unless I lower the pH with my experiments: Put acidic cracked corn (pH 4) in potting soil, and roses got rose-slugs from THINNER LEAVES in acidic rain (calcium, magnesium, and potassium drops when pH drops). Mirandy rose got a big-fat rose-slug on it for the 1st time. Why? It's next to a tree, and the tree robs the soil of calcium, magnesium, and potassium. Plus tree roots secret acid, so the soil became even more acidic with rain (pH of rain is 5.6). Used molasses, plus vinegar, plus sulfate of potash (21% sulfur), plus gypsum (17% sulfur) ... such acidic solution made leaves thinner, plus the stinky molasses really attract sawfly which give birth to rose-slugs. CONCLUSION: The best solution for pests is to raise soil pH by using dolomitic lime such as Espoma Garden lime (20% calcium and 10% magnesium). My soil is dolomitic clay, so I don't have midge, rose-slugs (sawfly larvae), nor aphids, unless I use acidic fertilizer. When there's tons of acidic rain, I throw pea-gravel on top of roses that like it alkaline, pea-gravel has many alkaline minerals to make leaves thick, glossy, and to prevent pests.