blaze, you have to qualify your advice more clearly for it to have any useful application. works better for what? there is no product on the market that is better at controlling apple scab and cedar apple rust than myclobutanil, as long as you aren't near a commercial production area where resistance has developed. brown rot on stone fruit is another story and the active ingredient in daconil is better for that.

I have commercial pesticides that do have freeze warnings but it is the water soluble bags that are damaged by cold temps. Main thing is to keep things dry. If you had Imidan you'd need to keep that from freezing because it is sold in those bags.

Usually skip this subject since I've no experience with sprays besides some traditionals like sulfur & copper used many moons ago on fruit trees. Given my ignorance & the range of opinions, hesitant to even stick a toe in these waters, but (here we go) feel the need to share some thoughts. We all acknowledge we can't grow some roses as perennials in the open garden due to intrinsic climate & site unsuitability, available space & individual practical considerations at any given time. We intentionally eliminate some roses from consideration for not meeting our bloom & growth preferences. Of those we do select, some will self-eliminate despite our care or be rejected down the road for not living up to expectations or no longer appealing as our tastes change. The most critical of my criteria for choosing any rose is its reputation for health & vitality in conditions similar to my own. Gardening more than 50 years in typically humid & fungal prone locations zoomed this to the top of the list long ago. Heavy physical reactions to all the "-cides" except elemental since childhood prohibits their use, as does my philosophical worldview. So I garden the old-fashioned way, pre sophisticated chemical compounds, by necessity. From my point of view, the health potential of any plant is expressed by positive response to its environment - nature vs. nurture - and the availability of the elements & conditions it needs to thrive tilt the odds to favor this expression. We all know moving a shaded rose into more sunlight often "cures" its blackspot outbreak, athough fungal exposure hasn't changed, and that roses sometimes outgrow these outbreaks with maturity. Believe boosting the plant's immune system by helping nature provide those essentials allows it to function optimally on its own, so concentrate my efforts on these aspects. (Same principles as human health. Incidentally, fortify my immune function with the internal products of plants' immune systems - essential oils - borrowing from the plants as it were, the core of traditional botanical medicine.) When we first came to this garden 16 years ago, it had been installed & maintained by a college groundskeeper for 7 years on heavy-duty chemical prevention principles. Extensive shrubbery had been maintained with yearly chunky woodchips atop that of prior applications - 6" worth suffocating the soil without deteriorating though covered in sour-smelling fungus. Couldn't find a worm wherever I dug outside the woods & not a bug, good or bad, in evidence besides mosquitos, flies & chiggers. The few roses were dwindling away under this treatment, bare shadows of their potential. Reversed that trend with organic husbandry & the worms returned. Fed the beneficial microorganisms that fed the worms that till & aerate the soil & the soil web reestablished itself to create an environment in which suitable plants can thrive. For years now, the gardens have welcomed a wide variety of inhabitants that appear to have found an interwoven balance with which I'd be loath to meddle. Beneficials & birds keep the ruffians in check most seasons with an assist from the hose. One year the garden club girls (one fellow joined as I was leaving) spent an entire initial meeting exclaiming about decimation the Japanese beetles wrought over the Summer. Apparently no one believed my surprise & report that only a few spotted here that season not far from their gardens, or they might have wondered what could be different here... Many roses brought in over the years, some with blackspot or mildew from travel stress, so likely a mix of farflung varieties present. Most got over it, as have those which arrived this humid rainy season, including a spotted Buff Beauty bought locally. Fungals show up here & there in small bouts with minor fleeting consequence (knock on wood). Still not brave enough to intentionally choose roses not known for their good health, some of those with mixed reviews doing well. Those among the dear departed were dispatched by deer, storms, cold, neglect & seeming suicide. Shovel pruned 2 for RRD. In my book, really not a bad record for all the years & varieties attempted. Saved a lot of bucks & effort counted up over time, alternately spent on new plants & garden stuff. But then, an admittedly lazy gardener relying on simple methods to support health, the weather gods (as do we all) & beneficial energies... Longwinded way of saying it can be done - growing roses naturally in the humid fungus-ridden Southeast - by way of encouragement to those considering a change of method & solidarity with those already doing it, too. This post was edited by vasue on Sun, Jun 22, 14 at 21:37

This is actually a pretty thought-provoking thread. I would like first to commend Carolyn on pointing to one of my favorite resources, extoxnet. Extoxnet is a collaboration of several well-respected universities (and certainly not corporate whores), synthesizing all of the available objective testing of these various chemicals. While I'm not trying to illegitimatize the premises of those who choose not to use synthetic chemicals (as I think Bigdaddy would attest, following a former back-and-forth we had on insecticides), I think it's extremely important to look at all the OBJECTIVE data in coming to conclusions on chemicals. Most synthetic chemicals, especially the old ones (e.g. Sevin) are extremely well-tested. Daconil, however, is probably one of the lesser-tested pesticides. Korney - you are also to be commended for putting all things in perspective on what home-use Daconil is. It very much DOES matter what the concentration is. After all, arsenic exists naturally in potatoes; cyanide in lima beans. There are many, many other examples. Hoosier, I respect your position and I, myself, try to avoid most synthetic chemicals until some other means fails. However, citing scorecard.org, a wing of the propagandist Green Media Toolshed (I encourage anyone to visit Green Media's mission statement as a reference) as your authority hurts your credibility somewhat (much like when my little brother attacks genetically modified plants by citing gmwatch.org). Such organizations (another example is the Pesticides Action Network) cherry pick the tests that serve their interests. It is similar, albeit on the opposite side of the debate, to relying only upon, say, Dow Chemical's testing to make your point. When comparing such a source to objective testing presented by extoxnet, extoxnet inevitably wins the credibility battle. Having said all of this, it is interesting that extoxnet reveals that chlorothalonil has only slight toxicity to mammals (mostly skin and eye irritation, both of which can be avoided by the most simple protective measures), the possibility to be carcinogenic in very high doses, a fairly moderate persistence in soil, and an unlikelihood to affect groundwater. With the testing available thus far, I will not hesitate to use Daconil sparingly, after a problem has arisen (and quite honestly, this is rare for me, and only on ornamentals; I don't have a lot of vegetable plantings at this time). The objective evidence simply doesn't suggest that limited home use will cause any appreciable damage to health or the environment. Finally, since DDT was mentioned, it is interesting that DDT was found to contribute, I recall, to only something like one single human death worldwide (a very unusual circumstance contributed to this). Also, it was not found to contribute to egg shell thinning, as was originally suspected. Interestingly, however, while pre-DDT malaria deaths (e.g., in Africa) were literally hundreds of thousands of times greater than when DDT was in widespread use, once DDT was initially banned in many such countries, malaria deaths rose, again, to pre-DDT levels. At least two scientists who recently wrote to the University of Iowa alumni magazine claimed that literally millions of human malaria deaths would have been prevented had DDT remained in use for mosquitoes, with no appreciable environmental impact. I think it is illustrative of the dangers of taking a "zero-tolerance" chemical attitude - allowing this attitude to trump both the hard evidence and the value of human life. Sorry if this is a little off-topic from Vince's initial post, but it helps to put things into perspective. Vince - it's ultimately up to you, but I see no reason you can't spray sparingly with a clear conscience.