Apple trees seem to have a disproportionate share of problems relating to brown leaves and brown spots on leaves. Careful examination of the leaf often gives an insight as to exactly what the problem is, but sometimes we need to dig a bit deeper to find the cause of the browning of leaves or the different types of spots found on the leaves of apple trees.
Most of the problems relating to brown leaves and spots can be easily dealt with. However, there are a few which signify the impending death of the tree.
There are four basic causes of browning on apple tree leaves, being pests, diseases, cultural activities and environmental inputs. Of those four possibilities, insect and other pests are the easiest to correctly diagnose.
Most pests can either be seen, or they leave visible clues, such as eaten segments of leaves. Depending on what part of the leaf has been eaten, apple tree pest damage can lead to brown spots on apple tree leaves, or withering of the whole leaf.
Brown leaves caused by assorted diseases can sometime be instantly recognised as being a disease which actually lives on the leaf, causing it to turn brown. These include fungal diseases such as powdery mildew or leaf rust. Some disease problems of apple trees are more difficult to identify, for they may be within the trunk of the tree or at the roots, but showing up firstly as brown leaves.
Fireblight is a disease that can affect Apple trees and all other members of the Rosacea family. The name is descriptive, and the tree will look as though there has been a nearby fire to one side of the tree.
Environmental problems which cause brown leaves on apple trees - rather than brown spots - include wind damage, late frosts, severe winter damage to root system, and airborne chemical damage.
Cultivation problems are also responsible for apple tree leaves turning brown, and these will include overfeeding, poor transplanting, or applying sprays at high concentration or in bright sunshine. Assorted soil problems will also fall into this category, from flooded soils, poor nutrition, and not least, drought effects.