Dr. Phyto

Japanese spiraea

Spiraea japonica

Diseases & pests on this plant

• Spiraea powdery mildewPodosphaera spiraeae

  A white to greyish, floury or powdery fungal coating develops on the upper and lower surfaces of young leaves, shoot tips and flower buds of Spiraea japonica. Infected young leaves become puckered, cupped, twisted or stunted, and new shoots may be dwarfed with shortened internodes. The coating starts as small superficial patches that merge into a continuous felt; heavily infected leaves yellow, dry at the margins and drop early. Late in the season tiny pinhead-sized fruiting bodies (chasmothecia) appear as black dots within the white mat.

• black bean aphidAphis fabae

  Dense black colonies on shoot tips + flower stems + young pods, sticky honeydew + sooty mould on lower leaves, stunted + distorted shoot tips, flower + pod abortion in heavy infestations, virus transmission causing leaf roll + yellowing later in season.

• grey mould (Botrytis)Botrytis cinerea

  Fuzzy grey mould on leaves and stems.