Are your peach leaves discoloured, curled up and grossly deformed? If so, you’ve probably got peach leaf curl – a common problem affecting peach and nectarine trees. Here’s how to prevent leaf curl as-well-as how to recognise it and what do if your trees are affected.
Peach leaf curl is caused by a fungus called taphrina deformans which overwinters in yeast-like form in your tree’s leaf buds until spring, when it strikes young leaves soon after they emerge. You’ll know peach leaf curl as soon as you see it: the leaves are misshapen, lumpy, often bright red in colour – and curl up; later, you’ll notice white fungus sores.
Your tree soon sheds its leaves and, if you’re lucky, will grow a second flush which won’t be infected, but this is not guaranteed. Twigs and fruit are occasionally infected but this is rare because taphrina deformans usually burns itself out by the end of May.
Peach leaf curl loves wet spring weather, so the best and most effective way of preventing it is to shelter your tree from the rain. Because many of us fan our peach trees against a wall or similar, building a lean-to from wood battens with plastic sheeting stretched between them, is a very effective way to stop your tree coming under attack.
Make sure you leave a gap at the bottom of your waterproofing to allow moisture to get to the roots, and leave the ends open to ensure adequate ventilation and to allow access for pollinators. Because leaf curl is a spring problem, once May comes around, you can remove your rain cover if you wish – there’s little risk of infection.
The kind of fungicides gardeners used to use to treat their peach trees are either no longer available or not recommended for home use. This being the case, the best way to treat peach leaf curl is to keep a sharp eye out for it and to remove any infected leaves as soon as you spot them, and certainly before white spores develop.
As always with fungal infections, you must dispose of any diseased material by burning or putting it out with the household rubbish; composting infected prunings only gives the spores somewhere cosy to spend the winter months. Do also remember to sterilise any tools and equipment you use to remove affected leaves before you move on to the next tree.
If you get peach leaf curl and your trees do produce new leaves, do make sure you fertilise and water your tree carefully to reduce the stress of putting out all that extra energy. Also consider thinning fruit quite aggressively to reduce the pressure on the tree’s resources.
Thanks to our wet springs, peach leaf curl is a common problem in the UK, but with vigilance, you can catch it before it really gets going,