Estimated reading time: 4 minutes
It’s common, particularly after rain, to see some brown rot developing in your fruit. Stone fruit is very vulnerable, especially apricots. However, you might also see it in peaches, nectarines, plums, or cherries.
Brown rot weather
You might have noticed that your fruit gets brown rot some years, but not others. Ever wondered why?
One of the main factors is the weather. Fungal diseases like (and in fact, need) moist conditions in order to thrive. Even though gardeners often look for rain to water the garden, dry weather is great for growing fruit!
Warm, rainy weather is such a risk to fruit growers that the Bureau of Meteorology even issues brown rot warnings. This is to let growers know that moist, warm conditions are on the way.
It’s a handy service to remind you to put your preventive measures in place.
Insects and brown rot
Notice how the brown rot often starts around a hole as you can see in the photo at the top of this blog?
The holes might be caused by any number of insect pests. Some of the main culprits are a tiny pest called Carpophilus beetle, garden weevils, or in this case, earwigs.
How do we know? Because earwigs classically leave tell-tale round holes in fruit that you can see in the photo.
Insects aren’t always the source of the disease. Brown rot spores may already be in the tree because it’s the same disease that causes Blossom blight in spring.
Blossom blight not only infects flowers but can also infect the wood in the tree. If you had Blossom blight, there’s an increased chance your fruit may also get Brown rot.
However, insects can also spread the disease around. They carry brown rot spores with them and infect the fruit when they eat it.
The combination of a small hole in the fruit, and a bit of rain can lead to a bit of a brown rot outbreak in your fruit tree.
Hygiene is really important
A lot of fruit that’s been infected with brown rot tends to fall to the ground. The infection can rapidly get worse until the fruit is completely covered by rot. This creates a lovely reservoir of spores on the ground which can splash up and infect any healthy fruit that remains on the tree.
Therefore, be sure to clean up any fallen fruit from the ground. If they’re not too far gone, you should be able to cut out the rotten part and eat or cook the fruit.
If they’re not good enough to eat, they can safely go in the compost, or animals like goats or chooks will love to eat them. This will help stop the spread of the disease this season. It will also help keep the tree disease-free next year.
It’s essential to remove any rotten fruit that you see in the tree, to stop the disease from spreading from one piece of fruit to another. Pieces of fruit that are touching are particularly vulnerable.
How to prevent brown rot from developing
Preventing brown rot, like all fruit tree disease management, relies on the 8 principles of disease prevention:
- Love your soil
- Prevention is easier than cure
- Protect the predators
- Encourage variety in your garden
- Hygiene, hygiene, hygiene
- Maintain your trees
- Monitor your trees regularly
- Plan your fruit tree garden.
How do you apply these principles to Brown rot? Luckily, you have a big “toolbox” of preventive measures. It starts with pruning your tree correctly to allow for good airflow, which helps the fruit dry quickly in wet weather.
Next, comes proper fruit thinning. If the fruit is not touching each other as it’s growing, it’s much harder for the disease to spread. Preventive spraying is also key, especially in wet years.
Lastly, garden hygiene is your friend. Removing infected fruit, cutting out infected wood, and preventing crawling insects from biting the fruit will all help.
Is it too late to prevent brown rot if I’ve already got it?
Luckily, the answer is no!
Some fungal diseases are untreatable once you have them. Leaf curl in peaches and nectarines is a classic example. But others, like brown rot, are definitely worth treating to stop them from spreading and getting worse.
The main solution is to use a “cover spray” of an allowable organic fungicide. We prefer sulphur, because it’s one of the least harmful, it’s relatively easy to use, and (if you use the right type) it can be very effective.
Apples are one of the most popular fruits to grow in your backyard. Learn the basics of how to look after your apple tree.
Using a fruit-picking diary can help solve the problem of choosing the exact time to pick your fruit so it’s neither under-ripe nor over-ripe.
Picking up your fruit from the ground is the first principle of organic orchard hygiene, and one of your best lines of defence against pests.