Daconil seems to be the fungicide of choice for BK.
2 Likes
Chlorothalonil, in other words. I believe I’ve heard it has the most, although inadequate, efficacy. Pasted this from the recommended list for the disease from Cornell.
| Fungicide | Application Notes | Examples of Trade Names |
|---|---|---|
| Captan | See label for timing. | Supra Captan 80 WDG |
| Chlorothalonil | See label for spray timing. | Bravo, Echo, Daconil |
| Copper products | Do not apply after full bloom. | Kocide |
| Lime sulfur | On peaches pre-blossom only. | Lime sulfur |
| Sulfur | First spray at pink stage. | Many names |
| Thiophanate-methyl | Apply at early bloom. See label. | Topsin-M |
2 Likes
Daconil is one of brand names of chlorothalonil.
1 Like
Read the label carefully. Only so much funginol and daconil can be applied during a season. Copper is fine but too much can lead to copper toxicity in the soil. Primary reasons why people give up on stone fruits in humid areas. The old rule of thumb is as soon as your new tree gets fruit, plant another one.
1 Like
But “Daconil” is easier to spell
4 Likes
Agree with @donwalker .
People who are new to spraying need to read label and understand REI (re entry interval) and PHI ( post harvest interval).
Chlorothalonil are for peaches, plums and cherries (but not rated for apples or pears). It cannot be used after shuck split until harvest.
Its use is limited. New gardeners who notice black knot in the summer on their plum trees (with fruit) may not know they cannot spray with this chemical.
1 Like
Do you spray Surround after shuck split on your peaches or are you still bagging?
Not for my computer, thank goodness.
If you cannot spray for the disease in spring it probably would be useless to do so by summer. At that point I’d only recommend cutting out the galls. As I recall the infection is mostly spread in spring but it takes a while for the galls to show. The first time you see them, just cut, you can spray the wounds with Captan if you like. If you are going to try additional chemical help, I think it’s best to do so in the spring.
“About the time new seasonal growth is ½ inch long, spores of the fungus are discharged from tiny sacs in the surface of the knots. These are spread by rain and wind to the new growth, where infection takes place. Spore discharge and infection are greatest during wet periods, at temperatures ranging from 55 to 75°F. Infections continue to occur until terminal growth stops. A few greenish, corky swellings may become visible the fall after infection occurs, but most will not be noticed until the following spring. Generally, the knots produce no spores until the second spring after they become visible. The fungus in woody tissues continues to grow in the spring and fall, increasing the knots’ length. Their eventual size depends greatly on the host species and cultivar.”
From Plum Disease - Black Knot
If you are going to spray for it in summer, it appears the disease only infects fresh tissue during relatively cool wet spells and cannot penetrate more hardened wood, so you can probably get as good control as possible by only spraying growing tips and green wood just below them by summer.
I use this approach to control oriental fruit moth with perfect success using a fraction of the pesticide needed to cover whole trees. .
2 Likes
Before bagging, I still need to spray Surround after shuck split at least once or twice while waiting for peaches to size up big enough to bag.
2 Likes
I’ve got my surround ready. We’re at petal fall with plums and peaches so it won’t be long now!
1 Like
What pests do you have there? Do you have plum curculio, Oriental Fruit Moth, coddling moth?
I have wasps that eat fruit and OFM. Some of the insects I see that pollinate are like giant black bees. They almost are the size of baby hummingbirds. Canker is my biggest enemy so far! We also have big white fat grubs in the soil, but I do not know what insect they turn into. Here’s the great news…no squirrels! I will need netting for birds and surround. The giant white grubs were cicadas! They were huge! I left them on the wall for the birds to eat. They loved them!
2 Likes
You may get better result spraying with Spinosad or mix Spinosad with Surround. No sure you need Surround with what you have,
1 Like
Can’t get Spinosad. Our chemicals do not exist here in our stores. The closest I have gotten to a chemical for home use is copper.
2 Likes
I erased my mistake so any confusion won’t lead to violating the label.
1 Like
First line, page 10
I was fooled by the 5 apps per season and assumed that was the only restriction. I just can’t imagine spraying a tree 5 times before shuck split so jumped to the conclusion because I’m used to a different format on commercial formulas where the restrictions usually come first.
One thing people, who are new to spraying fruit, need to keep in mind is that you need to read the label all the way through. When it says Chrolothalinil can be sprayed every 7 days on cucumbers and carrots, it does not mean the same approach can be applied to fruit like nectarines, peach, plums,etc.
Often, it does not appear to make sense but labels are laws.
We need to follow the label. Do not assume.
2 Likes