What's eating my cotoneaster bonsai?

Cotoneaster bonsai (Cotoneaster horizontalis) is most troubled by woolly aphids, which form white cottony masses on stems and roots. Scale insects crust over branches. Hawthorn webber moth caterpillars web leaves together and devour them. Fire blight bacteria can devastate the plant after insect feeding wounds provide entry points. Birds eat the berries harmlessly.

White or blue-grey woolly masses on stems, branches, and sometimes roots; galls form below soil level; infested bark cracks and develops cankers Scrub off colonies with a stiff brush dipped in methylated spirits or insecticidal soap solution; apply systemic insecticide (thiacloprid) for severe or root infestations; check roots at repotting

Flat or domed waxy brown scales on stems and undersides of leaves; honeydew and sooty mould; weakened growth and die-back Horticultural oil (winter wash); scrape off with a soft brush; acetamiprid or imidacloprid drench for persistent infestations

Silken webs binding leaves together; caterpillars skeletonise leaves inside the web; heavily attacked shoots turn brown and die Remove and destroy webs and caterpillars by hand; spray with pyrethroid or Bt inside the web in spring when caterpillars are small

Shoot tips die back suddenly and turn brown, remaining attached (shepherd's crook); flowers blacken; disease spreads down the stem Cut infected shoots at least 30 cm below visible damage; sterilise tools between cuts with bleach or methylated spirits; no effective chemical cure — prevention through vigour management