Hi! A few people in my AMAZING gardening group had questions about brown rot. I recently purchased a house and the two peach trees in my backyard have severe brown rot. SO I went on Google Scholar and read a lot of academic papers on how to best treat the disease. This is what I’ve learned.
- The first thing you want to do is figure out how tall your tree is, approximately. That will help you create a budget. As much as no one wants to ever cut down a tree, sometimes that’s just the most cost-effective way to manage brown rot.
- A little about brown rot… all peach trees are probably going to get brown rot (a fungus) at some point. It’s really a matter of just managing it. Other stone fruit trees can also get the disease. Brown rot attacks twigs and leaves but the main issue is when it gets to your peaches! Once brown rot attacks, it’s only a matter of days before the entire peach is mummified and destroyed.
- The time to act is now, in the winter. Make sure you collect any mummified peaches that are still on the tree or have fallen to the ground. The fungus likes to overwinter in these peaches. Do NOT compost the dead peaches. Put them in a sealed bag and throw them away so as not to spread the fungus.
- Identify branches and twigs that are dead and prune these off. The fungus lives in these dead areas and will come back during spring. Also look for branches that crisscross each other and prune one of them off. When the wind blows, the branches will rub against each other and create a raw spot that can then become infected by fungus or pests.
- Use the right tools. I’ve done hours of research, and here’s what I’ve found works the best. It’s pricey, which is why you want to have a budget. And why can’t you just use the shears you’ve had for years? Rusty, dull shears won’t create clean cuts and it’ll take longer for the tree to heal, which leaves more opportunities for those areas to get infected. This is the best pair of basic pruning shears that gardeners on multiple review sites swear by. This is the best ratchet lopper for getting bigger branches. Here’s the best pruning saw for heavy duty pruning. And, if you have a tall tree like I do, this is the best extendable pruning saw that’ll keep you from having to climb a ladder while wielding a sharp object! Safety first!
- When you prune, make sure to clean off the shears with a solution of bleach after EACH time you make a cut. This will prevent the spread of infection. Take the branches that you’ve pruned and put them in a bag and throw them away. Do not compost.
- When the tree begins to fruit, prune off any new peaches that are too close together. Keep each fruit at least six inches apart. That way, if one becomes infected, it’s less likely to infect the others.
- You’ll also need to buy fungicide. According to some recent academic studies, you can use copper fungicide with “moderate” success. Scientists recommend using a combination of fungicides such as: Merivon, Indar and Luna Sensation. Indar + Luna Sensation had a success rate of 91% when combating brown rot! The reason you want to use two to three different types of fungicide is that brown rot can very easily become resistant to a fungicide when it is applied often.
- “Small handheld sprayers are suitable for a single tree and a larger backpack sprayer is preferable for spraying multiple trees at once. Spray all the surfaces of the tree thoroughly, as well as the ground underneath the tree; the fungus that causes brown rot overwinters throughout the tree, especially inside the crevices of tree bark and on any debris on the ground. A good rule of thumb is to use one gallon of the fungicide solution for every 5 feet of tree height and width. For example, a tree 15 feet tall and 10 feet wide takes about 5 gallons to thoroughly cover the entire surface area.” Source
- You’ll want to spray three times. Once, right as the tree is budding. Another time three weeks later, and a third time about one week before the fruit is ripening, when it has color but it’s not ready to pick.
- Finally, check your tree for cankers. Here’s how to handle them: Link here and this is the knife I’d recommend.
Let me know if you have any questions! After creating a budget for my trees and taking into account the cost of pruning and applying fungicide to 20-foot-tall branches, plus removing cankers, the most viable option is for me to cut down the trees and start over with dwarf peaches that I can care for more easily. I hope this research helps you make the right decision for your yard!
Photo Credit: Charles Deluvio