Dr. Phyto

sweet chestnut

Castanea sativa

Diseases & pests on this plant

• Asian chestnut gall waspDryocosmus kuriphilus

  Pinkish-green to red galls 0.5-2cm forming on developing leaves + shoot tips in spring, severely galled trees produce few or no nuts, gradual general tree decline over 3-5 years of heavy attack, old galls dry to brown and remain on branches as inoculum reservoir, infested shoots fail to lignify before winter.

• chestnut blightCryphonectria parasiticaEU-notifiable quarantine organism

  Sunken orange-brown cankers on bark with cracked + raised edges, bright orange fungal stromata (pinhead-sized) embedded in canker surface, complete girdling + death of branches above canker within 1-2 years, characteristic epicormic sprouts below canker after upper branch dies, eventual tree death over 3-8 years in classical virulent strains.

• chestnut leaf spotMycosphaerella maculiformis

  Small (2-5mm) reddish-brown leaf spots with grey centers, spots coalesce into large necrotic blotches in heavy infections, premature leaf drop in late summer, weakened trees with reduced winter hardiness + lower next-year yield, no fruit symptoms.