I am sorry for your problems with peach leaf curl. So far I have been able to avoid the problem with one spray of Kocide when applied at first bud color. Maybe this, the rainiest March in history, will also be the year I get curl. Al

Sometimes ordinary mortals can take a test and get an applicator's license. I don't know if this is true in your part of the country. Once you've got the license, you can buy some truly nasty concoctions.

How much is the cost? If it is free then I would have taken it already. If it costs $$$ per year for renewal and the time and hassle of taking it and renewing thereafter, to spray one peach tree? That is truly ridiculous!!!

I moved into a new house in the Glen Park/Sunnyside neighborhood of San Francisco in December. There is an established small orchard of a dozen fruit trees in the backyard (all over 5 years).

In December, the peach tree still had some leftover leaves on it - which exhibited Peach Leaf Curl (PLC).

After some research, I found copper was not the cure for PLC - lime sulfur is. Evidently, most people prefer to use copper products over lime sulfur products - but it doesn't work well (if at all) for PLC. But DON"T use lime sulfur on your apricots!

I purchased some lime sulfur concentrate online and had them send it to me here (couldn't find any in SF). It was reasonably priced. Used a powerful dose in January from a tank sprayer when everything was sound asleep. I think the directions were four times normal dose (was on label).

The peach tree is leafing out now, and though I didn't expect to defeat PLC this year (figured I would have to wait until next) - so far the leaves are not curling.

I haven't given a second spraying of lime sulfur at the normal dose yet. Don was recommending after petal fall, so I am waiting for that.

Worst than PLC are the brown rot, blossom rot, blossom blight and twig blight on both the peaches and apricots during the first pink to peak bloom. Copper based fungicides and to certain extent Captan, minimizes that, lime sulfur won't be applicable at bloom, but with all the record number of rainy days during the peak blooms we're having, sprayed them religiously or not, for sure there will be rots and blights.

Lime sulfur damages cots and their hybrids, but not so hard on pluots. I have about 30 kinds of stone fruits on one tree, from cherry to peaches, apricots, plums and their hybrids, so lime sulfur is not the answer. Overall more than 330 cultivars in my tiny yard (750 sq ft of 45 planting holes along the border) in this "crowded" city where prices of land is at a high premium compared to neighboring areas.

Lime sulfur is good for grafted trees that are just pure nectarines or peaches, but not with something else on that same tree or if planted far from other cots. Neighbors would cry foul if they would get a whiff of that horrid smelling lime sulfur sprays.

Lime sulfur is available at OSH, Home Depot (seems to be absent recently) and Ace Hardware as well as most nursery stores.

Ziram is a promising one, twice more effective than Kocide, says Dave Steele in some research in Oregon. Does anyone know where we can get Ziram? Will it damage apricots?

Morphol Embryol (Bucur). 1983 Jul-Sep;29(3):159-65. Related Articles, Links

Decreased fertility, increased dominant lethals, skeletal malformations induced in the mouse by Ziram fungicide.

Cilievici O, Craciun C, Ghidus E.

The toxic effect of the Ziram fungicide (Zn-dimethyldithiocarbamate) on fertility, its lethal and teratogenic potential were tested on two mouse strains, C3H and AK. The fungicide was administered by gavage to male mice in daily doses of 0.2 mg% and 0.1 mg% along three weeks, then the mice were mated with normal females. Ziram induced changes in the testes and meiotic chromosomes. From among the mated females, 80 per cent of the C3H mice and 20 per cent of the AK remained unfertilized. The dominant lethals have a higher incidence in the AK strain. The skeletal malformation induced were kyphosis, scoliosis, sternum ossification failure; retardation in skeletal development is more obvious in the AK strain.

Here is a link that might be useful: Ziram

I don't spray, but once the leaves are out I put the yard waste recycling bin in the area and pick off each and every leaf and send them to yard waste. The tempetures get to 170 degrees out there and kills the virus. This year will be bad because of all the ##%%@@ rain. I am getting gills and webbed feet.

Penny

I am licensed pesticide applicator. As mentioned in the other forum, there are more chemicals available to the commercial grower, but nothing I would classify as nasty , at least related to fungicides. We use Koicide and Oil sprays that are the same as what is purchased at the hardware store to control things like peach leaf curl

It used to be that one could by fungicides like Rovral over the counter until the manufacturer stopped packaging it in small quantities.

There is no cost to obtain a license. A licensed pesticide applicator is someone who is licensed to use restricted materials. Those are typically pesticides that are labelled dangerous. I have to take a test once every couple of years to renew the license. Most fungicides and herbicides fall under the unrestricted category and don't require a pesticide applicator's license. All that is needed is anrestricted permit issed by the County's Ag Extension office. I don't know whether they issue those to city folks or not.

I've had fair luck with sulphur. You must use it before the fungus spores germinate, and you need to apply it after every rain, top and bottom of the leaf. It also controls powdery mildew and several other diseases that are problems on members of the rose family.

The problem with the home-use fungicides is they are no longer effective because the fungus have become tolerant of them.