Interesting paper from Russia where they tested a combination of growth regulators to combat PLC and get controls on-par with traditional fungicides. Colloidal Silver looks promising as a contact fungicide and replacement for copper for people like me concerned with building up copper in the soil.
https://iopscience.iop.org/article/10.1088/1755-1315/723/2/022058
Very interesting link. I wonder how fruit ripening was afterwards? Colloidal silver blocks ethylene production in dicot annuals. Or if would effect ethylene production in fruit trees that use ethylene as a ripening hormone.?
FYI I plan to try the KMnO4 for curl this spring. I love the idea of it and it is very low $$. I just cannot live with myself spraying copper into our creek knowing how bad it is for fish and invertebrates. Copper royally fu**s stuff up in aquariums. Kills all the snails and shrimp and small food bugs in the system. Destroys the olfactory scent organs of almost all fish. Just a few drops…. I would not be surprised if someday copper is treated like lead. Not to be spread Willy nilly all over the place. Or mercury.
It’s all about concentration. From the perspective of where deciduous fruit trees evolved, many of us are sorely lacking copper in our soils. In many cases it is the reason maladies are present.
A member introduced a treatment,which I haven’t tried.It worked for him,at his location.Maybe something to experiment with.
The product they have used here has 500mg/L colloidal silver. I see there are plenty of colloidal silver products here in USA for humans, but as any supplements difficult to evaluate their claims on whether there is any active ingredients.
The best way to mix colloidal silver into a garden use solution is to sodium thio sulfate. Makes silver thiosulfate.
My point is this:
Many of us seek out advanced fruit cultivars. These plants evolved in a totally different ecosystem and then were bred for a hundred years or more in environments using serious chemical controls for pests and disease. Then some of us plant these cultivars and expect to use soils and control systems that significantly differ from the plant history.
It would be less effort to breed a plant suitable for the environment you desire.
so far I have come across good research activity in Europe to breed resistant types. There are a few resistant types bred in Italy cultivars DOFI-84.364.060 seems to be promising. I don’t think these are available in US and in general there is any disease resistant research going on in the US. It’s funny that some of the PLC resistant varieties were discovered accidentally. Like the Betty peach which was growing in Betty’s compost pile.
location matters. I don’t think this approach will work in rainy part of PNW. I will be trying oxidate which is essentially premixed high strength H2O2 with peracetic acid. I have a test nectaplum tree that I bought month and half back for this purpose.
they don’t talk about it in their paper. perhaps the concentration of 500mg/l doesn’t prevent ripening.
I’d sort of think “pristine fruit; never ripens” would come up if it were a problem.
Hi Brady,
Have you tried this one? “ Safe Organic Control Of Peach Leaf Curl and other Fungal Diseases” by Joereal?
I did not have curl on my peaches but I had some curl on my plums and some type of infection that defoliated a number of my plums in one area, most grew foliage back later but some branches may be lost. I’m not sure what caused it but this was a very dry summer and perhaps my watering was insufficient.
So I had contemplated using daconil as a fungicide, but after reading this method I am tempted to try it instead on plums and peaches
Dennis
Kent, wa
Betty is my best tasting peach (compared to Avalon Pride, Salish Summer, Curl Free, and Nanaimo) but it’s definitely not PLC resistant in my fungal paradise. Untreated it gets 95% curl. Treatment over its 10 year lifespan has progressed from homemade Bordeaux mixture (50% curl) to Kocide 300 (25% curl) to Ziram (0-5% curl).
Are you growing Betty with no PLC?
I have seen Betty listed as resistant to PLC.
Hi Dennis,
Not yet.It almost sounds too good to be true,especially in the wet PNW springtime environment.
Did the Plum leaves curl at all?If so,that might be caused by Curly Leaf Aphids.These insects seem to be controlled by Joe’s concoction as well,at least he reports of having none.
I think trying it here,at least on a tree or two,might be interesting.
I will send you a pic or two tomorrow of some curling
I second that. My betty I got from raintree gets curl very bad. Not a leaf spared and complete defoliation before regrowing foliage without curl.
Not if it was only tried on young trees, since they are often more prone to curl. I was not sure if it was a small test plot or the whole orchard. I could not read the full article, only the abstract.
It will work for areas like San Fran bay or so-cal or E.OR/WA where there isn’t much back to back rain and winter dampness.
The challenge with surface fungicides in our area is not so much as whether they are capable of neutralizing the pathogen but how long as they remain on the surface without getting washed away from the rain. When using fungicides which work based on oxidization i.e. Joe’s formula, Oxidate, Potassium Permanganate etc. they need to be applied often repeatedly and keep the pathogen load low. Once the tree is dormant, spray the wood until run-off as many times as possible.
Copper and Zinc works because they metal particles that adhere to the spots where the pathogen can enter much longer than oxidizers. Especially when used with a good sticker.
this is only needed if you want to use Silver to prevent ethylene related flower degradation. For fungicide action mixing Silver Nitrate in water at 100ppm and spraying will do.
I found this old dissertation from a grad student in Oregon State University evaluating silver as a fungicide.
TLDR:
I think if for some looking for an alternative to copper, this is the silver bullet. However, since silver is also bad for fish ppm should be carefully selected. But, much better than copper which for products like Kocide containing 30% metallic copper.
Options to use silver:
Use silver nitrate reagent diluted in water to achieve 50-100ppm and spray with modern stickers like Nufilm.
Use simple electrolysis to create a solution with silver ions and spray within 2 days.
Buy silver nano particles, dilute to required ppm and spray with a sticker.
GuilfordRogerK1963.pdf (7.9 MB)