We had a great question from one of our Grow Great Fruit growers about what causes these brown marks on the skin of their apples.
It’s called “russet”. It describes both the yellow marks (as you can see on the side of this Cox’s Orange Pippin apple), and the rough brown marks around the stem end of the apple.
Russet is one of those curious conditions that occur naturally. In fact, several heritage apple varieties include it in their name. Brownlees Russet, Egremont Russet, and Old Somerset Russet are just a few.
Russet is also commonly seen on pear varieties such as Beurre Bosc, like this trio of beauties:
Why are russeted apples so rare?
Brown marks such as russet are not considered an attractive trait on modern apples. Have you ever seen a russeted apple in the supermarket? It’s just one of the reasons many of these beautiful old varieties have gone out of favour.
This is one of the reasons we’ve planted a new heritage apple orchard on our farm – to preserve many of these old varieties.
We think apples are one of the best fruit trees to include in your garden. In fact, we’re building a collection of rare and unusual (but useful) varieties on the farm. At the moment we’ve got about 30 varieties and we’re aiming to build this up to about 100.
But back to brown marks on apples …
When brown marks on your apple are a sign that something’s gone wrong
Russet can also be an injury caused by environmental conditions like frost, sunburn, or hail. Spraying your apples at the wrong time can also cause it.
Even using sulphur (which is an organic fungicide you can safely use) at the wrong time can cause russeting on some apples.
This damage-type russet (think of it like scar tissue) usually happens in the three weeks after petal fall. It can also occur when the trees are flowering, or when the environmental challenge occurs.
It is often not a problem in itself, but it can make the apples much more vulnerable to other diseases. Various fungal rots, cracking, or even sunburn are often seen together with strong russeting.
Heritage varieties that were bred in the UK, such as the divine Cox’s Orange Pippin apples (above) or the much-loved Bramley (below), are not well suited to the harsh and hot conditions in much of Australia. It’s very common to see this type of damage on these apples.
You can aim to create micro-climates that these trees will prefer, and you may find that much of the damage is preventable.
Learn more about creating micro-climates in your garden in Permaculture in Action. This short course shows you how to create the right conditions – or finding existing pockets in your garden – to grow a wide range of fruit outside of its preferred climate.
It’s a great way to extend your fruit season, and to increase the variety of fruits in your diet.