Due to the excessive amount of rain and humidity last summer I lost all my stone fruit to Brown Rot. This is a fungus that literally causes the fruit to rot and turn brown, hence the name.
It can affect the plant at various stages of growth, causing blossom to turn brown, wither and die or the fruit to rot and fall and/or become mummified and hang on the tree throughout winter. It can also cause cankers and growth distortions in branches.
Whilst I was aware that the fruit had rotted, it was not until I removed the protection netting did I find all the mummified fruit.
Now the key to managing this disease in good sanitation.
The first thing is cleaning up any mummified fruit on the tree or the ground. Ideally I should have removed the rotting fruit before it become mummified. The fallen rotten or mummified fruit must be destroyed not composted as Ib need to try and eliminate the fungal spores from the surrounding area.
I have done some research and found a number articles relating to the control of brown rot.
Peter Cundall suggests that along with good sanitation you should spray with a Bordeaux or burgundy mixture when the tree is dormant. Here is a link to this information and recipes for the mixtures: http://www.abc.net.au/gardening/stories/s1631445.htm
Justin Russell from Organic Gardener suggests spraying with lime sulphur whilst the tree is dormant and then copper hydroxide at bud burst.
There have also been some successful trial using a combination of compost tee and algae based solutions and rock dust.
Now I am assuming that all of the above products enhance the health of the tree and increase its natural resistance to becoming infected so I will try these as well.
So here is my list of cultural and preventative practices I will be doing over the following 12 months to try and manage this disease.
- Remove all rotting fallen or mummified fruit as soon as observed. Destroy don’t compost.
- In winter I will prune to open up the frame work of the tree to ensure good air circulation and allow plenty of sunlight into the middle of the tree. Both circulating air and sunlight reduce the build-up of humidity. Humidity increases the incidence of the fungus.
- Remove and any wood that is affected i.e. that have developed cankers or distorted growth.
- Apply Bordeaux mix during the winter.
- In spring applying a granulated organic fertiliser containing rock dust.
- During the growing season apply regular applications of compost tea and Seasol.
This may seem like a lot of work but with only a small number of stone fruit trees I should be able to do all of these things in an hour or so every few weeks and to me it is worth the effort as I just love the taste of sun ripened juicy peaches and nectarines.