A lot of people don’t think “organic” and “spray” go together, and while it’s definitely better to aim for a healthy, biodiverse system that keeps itself in balance without any spraying at all, there are actually a couple of sprays that certified organic growers can use to help things along the way (under strict organic standards, of course).
The only sprays we ever use on the farm are these allowable fungicides — a little bit of copper, and elemental sulphur — because in a wet season they can make a huge difference in preventing some particularly nasty fungal diseases if you use them in spring.
You may have seen recommendations to spray fungicides on fruit trees after the crop has been picked in autumn, to clean up any residual disease, but this is a bit more controversial.
So, when is the right time to spray? Do your fruit trees really need an autumn fungicide?
The answer is … sometimes!
In our short course Keep Your Fruit Trees Free From Disease we detail those diseases that can benefit from an autumn spray of an organic fungicide, under certain conditions, like having experienced a bad case of brown rot in the previous summer.
So we certainly don’t rule it out, and it can be a useful part of an overall strategy for cleaning up some diseases. However, in most reasonably healthy trees, you don’t need to routinely use a fungicide.
And that’s a good thing, because even organically allowable sprays can have an impact on the environment, particularly the soil, and you should only ever use the minimum amount necessary, and strive instead for a really rich biodiverse garden where natural immunity will be at its highest. (And you should never use chemical fungicides.)
If you’ve had a dry summer- as we have in central Victoria this year – there’s been very little fungal disease in the fruit, and only a little in the trees.
Under these conditions our recommendations include pruning any diseased wood out of the tree (and totally removing it from the tree and the orchard floor), but no need to put on a spray at all. Excellent!