What's eating my cotoneaster microphyllus?

Cotoneaster microphyllus shares the pest profile of all cotoneasters: woolly aphid is the primary insect pest, building white cottony masses on stems. Scale insects and spider mites affect denser, small-leaved bonsai cultivars. Fire blight is the most serious disease risk, often following physical injury or insect damage to new shoots.

Distinctive white fluffy masses on stems and in branch forks; gall formation and bark cracking; ants may be seen farming the colonies Scrub off with a brush and soapy water; systemic insecticide for root woolly aphid; check all roots at repotting time; ensure good air circulation

Fine stippling and bronzing of the tiny leaves; webbing in the dense canopy; leaves dry out and drop; worse in hot, dry weather Increase humidity; strong water misting; predatory mites on bonsai; miticide (bifenazate) in summer if populations are high

Hard or soft waxy scales on twigs; honeydew attracts sooty mould; die-back of individual branches Winter wash with horticultural oil; physical removal with a soft toothbrush; systemic drench in spring when crawlers are active