Woolly aphids are easy to spot. You’ll see fluffy, ‘woolly’ blobs on the stems of apple and pear trees. If you pull those woolly threads apart, you will see aphids sheltering inside. These sap-sucking pests generally appear on older trees or where there’s environmental stress, such as excessive shade or lack of water. In autumn, they tend to move down to the roots and inflict even greater damage. You can remove woolly aphids with your fingers (wear gloves; they produce a sticky red mess when squashed), but they’re likely to reappear in a week or two. Keep squishing, or use a pyrethrumbased spray (these are contact sprays), or a systemic spray. Or paint with methylated spirits, using a small paintbrush. If using contact sprays, make sure you get beneath the woolly covering.