Leaf curl (Taphrina deformans ) is that horrifying-looking disease your stone fruit get where the leaves curl up and dye and your yields are drastically impacted. Leaf curl predominately affects peaches and nectarines, but can also hit apricots and almonds.

Leaf curl in action – yuck. 

We have a mixed orchard which includes some stone fruit – our nectarine tree is the only one with leaf curl…

Our winter orchard. For those of you who are interested, this particular row of trees has been pruned to a rough espalier “fan” shape to be more space efficient.

Where does it come from?

While it’ll start to show up in early spring it’s actually been living in your trees over winter, dormant – waiting for the seasonal rains to come and spread it into every little nook and cranny throughout the tree.  Effective treatment must begin when an affected tree loses its leaves in late autumn or early winter.

So what do you do?

A number of things, but two of the most important ones are:

1. Before the tree buds swell spray it with lime sulphar. The lime lodges around unopened buds providing a temporary rainproof seal. Warning the lime sulphar smells like rotten eggs.
2. When the buds are swelling (opening) usually in late winter/early spring, spray it again with Copper oxyxchloride  – this kills the fungal spores. If you’re a bit late to the spraying party and your tree’s buds are already swelling (so can’t do the lime spray), go straight to the copper spray – it’ll still worthwhile.

Be sure to spray on a still day (wind gets a bit chaotic and messy) and that it’s not about to rain (it’ll wash it away).

Both treatments mentioned above can be sourced from your local nursery – they’ll provide details on quantities to use.

Importantly, once leaf-tips appear, it’s too late to do the above treatments – timing is everything! I literally put these treatments in my diary a year in advance so I don’t forget – I recommend you do the same :-).

Lime sulphar mix ready to go

Make sure you drench the trees with the spray to ensure it gets into all those nooks and crannies.  

Other things you can do as well

For the best results in controlling leaf curl, use a number of control methods together. Complete elimination can be challenging, but the impact on the tree and fruit production can be minimised.

• Clean up any fallen leaves from previous infections and dispose of in the bin to minimise hiding places for the fungus spore.
• If a tree is already infected, remove all distorted leaves and fruit and destroy (bin or burn them).
• Feed your soil with slow release organic fertilisers and soil conditioners, as well as regular watering regimes, to ensure it is healthy and can recover from infection.

A healthy tree = more fruit

If you don’t treat your trees than your yields will go way down and the fruit you do get will be small and deformed – and it’s likely you’ll cry. While the year of 2020 is throwing a hole lot of shite at us – lets not add leaf curl to the list. So if you’re privileged enough to have a fruit trees – have a crack at maximising what you can get from them.  Cause the more you have, the more you can share with your community :-).

More resources

• Sustainable Gardening Australia
• Gardening Australia
• Peter Cundall