There are many different virus diseases of stone fruit and pome fruit (apple and pear) trees. They can affect fruit (size, shape and quality), but what you’re more likely to notice is the symptoms on the leaves, especially colour patterns and distortions. They can also cause dieback, bark symptoms, gumming, stock–scion incompatibilities, and even tree death! Some produce distinctive symptoms, but others are much harder to see. Your fruit trees may even be carrying a virus that is completely symptom free!
Read the article in Summer – Week 3.