I have an apple tree which we have pruned back recently. Along the branches and trunk (especially where it was pruned back) it is covered in a white, fluffy fungus or something similiar. What is it and how can I treat it?
26 April 2019 08:51 PM
From your description, it sounds like your tree has been attacked by Woolly Aphid, A colony will appear as a cottony mass generally clustered in wounds and pruning scars on the trunk and branches of the tree. Woolly aphid is a sap sucking insect that weakens the tree by feeding on the limbs,twigs and roots of the tree. The aphid is purplish in colour but as they develop they gradually cover themselves with masses of white waxy threads. This pest feeds on the root system throughout the year. Above ground the population decreases in autumn as aphids migrate to the root system and increases again as the weather warms up in spring when they will move up the tree onto the new growth. This particular aphid is usually kept under control by a small parasitic wasp which lays its eggs in the aphid bodies. The wasp eggs hatch and the wasp larvae develop inside the aphids and destroys them. Unfortunately if pesticides are sprayed, these small wasps are often killed. At the present time the colonies can be removed with a forceful jet of water or can be rubbed away with a brush and soapy water. When the apple tree has lost its leaves and is in its deciduous stage, the tree can be sprayed with a solution of Lime Sulphur. Make sure that all the crevices, where the woolly aphid is likely to over-winter, are thoroughly sprayed.