Why Early Detection Saves Your Crop

A traditional orchard is not a tidy place, and the trees in it are rarely picture-perfect. A little scab on the fruit, a rough patch of bark, a few mildewed shoot tips — these are the ordinary companions of unsprayed apple growing. The trick is knowing which blemishes are cosmetic and which ones will hollow out a tree over three or four seasons. Scab, canker and powdery mildew are the three problems you will meet most often in a British orchard, and all three respond far better to early intervention than to drastic surgery later on. Get into the habit of walking your trees once a fortnight from bud burst through to leaf fall, looking at leaves, fruit and bark in that order.

Apple Scab: The Olive-Blotch Problem

Scab is caused by a fungus that overwinters in fallen leaves and releases spores during wet spring weather. You will first notice it as soft, olive-green to sooty-black velvety patches on the upper leaf surface. Later the leaves yellow and drop early. On the fruit, the same infection appears as corky brown scabs, often splitting the skin and letting in secondary rots.

• Look for: velvety olive blotches on leaves, corky brown patches on fruit, premature leaf fall in midsummer.
• Act early: rake up and burn or bin fallen leaves in autumn — do not put them on the compost heap, as the fungus survives there.
• Prune for light: open up the centre of the tree so leaves dry quickly after rain.
• Traditional sprays: sulphur or lime sulphur applied at bud burst and again at petal fall can reduce pressure in a bad year.

Some varieties shrug scab off almost entirely. If a particular tree in your orchard is scabbed every single year while its neighbours are clean, that is useful information — it may be the wrong tree for your site, and better suited to a rough cider blend than to the eating apple basket.

Canker: The Bark Wound That Keeps Spreading

Canker is the disease that ends old trees. It appears as sunken, dark, dead patches of bark, often around a pruning wound or a leaf scar. In damp weather you may see small creamy-white pustules with red centres breaking through the surface — these are the spores, and they spread on wind and rain splash through autumn and spring. A girdling canker will cut off the flow of sap and kill everything above it.

• Look for: sunken cracked bark, dieback on shoots and branches, red-tinged pustules in wet weather.
• Cut clean: prune back to firm, pale, healthy wood, going at least 10–15 cm beyond the visible edge of the canker.
• Burn the waste: do not leave infected prunings lying in the orchard.
• Clean your tools: wipe secateurs and saws with methylated spirits between trees, especially after cutting out canker.
• Choose dry days: prune in dry weather, ideally late winter, so wounds have the best chance of sealing.

Powdery Mildew: The White Dusting

Mildew shows itself as a grey-white powdery coating on young leaves and shoot tips, which then curl, stiffen and fail to extend. Fruit set can be poor, and any apples that do form may be russeted or small. Unlike scab, mildew does not need free water on the leaf — it thrives in mild, humid, still conditions, which is why crowded trees suffer most.

• Look for: white powdery patches on shoots, curled and stunted growth at the tips, silvery scarring on young fruit.
• Remove infected tips as soon as you see them in summer, cutting back to clean growth.
• Winter prune hard on badly affected trees, as the fungus hides in dormant buds.
• Ease off the nitrogen. Soft, sappy growth from too much feed or muck is mildew's favourite food.
• Keep the roots watered in dry spells rather than the foliage.

Airflow, Spacing and Orchard Hygiene

All three diseases share the same ally: still, damp, crowded air. Everything you do to open up the canopy pays you back twice. Thin out congested branches, remove rubbing wood, and keep the grass and nettles around the trunk cut back so air moves at ground level too. Mulch around young trees to conserve moisture, but keep the mulch a hand's width clear of the trunk so the bark stays dry.

Feed with a balanced fertiliser or well-rotted manure in late winter rather than a nitrogen-heavy one in spring, and consider a potassium-rich feed in summer to firm up growth. If you are planting new trees, leave proper spacing — a traditional standard apple wants eight metres or more, and even a half-standard needs five. Cramped trees will always be diseased trees.

What This Means for Small-Batch Cider

Here is the encouraging part. Scabbed and slightly mildewed fruit is perfectly usable for cider; in fact, many traditional bittersharp and bittersweet varieties are grown precisely because they tolerate these blemishes and still press into a fine, tannic juice. Wash the fruit, cut out the worst, and press on.

But be strict about rot. Fruit with brown rot, canker lesions at the stalk, or any mould should go straight on the bonfire, not into the press. Mouldy apples can carry patulin, a mycotoxin that survives fermentation and ends up in the bottle. A clean, dry, well-ventilated orchard is not just prettier — it is the first step towards cider you can be proud of.