Posts Tagged ‘Gymnosporangium juniperi-virginianae’

Who has seen what? May and July 2015

Friday, July 17th, 2015

Our comon friends, the Juniper and the Hawthorn, share a fungal pest which requires both these plants be present and near enough to each other to allow transport of fungal spores from one to the other.

JuniperGall#1-DSC08556Click image to view

Gymnosporangium spore forming bodies on Juniper seen each spring at Ardgay.

Gymnosporangium juniperi-virginianae is the fungal pest which in turn attacks Juniper, then Hawthorn.  Juniper is infected in mid to late summer by spores created within galls on Hawthorn.  After over-wintering spring moisture causes Gymnosporangium galls to form on the Juniper.  Spores from the Juniper infect the Hawthorn.  This heteroecious cycle repeats.

HawthornGall#1-DSC08886Click image to viewGalls which form each summer on Hawthorn at Ardgay.

HawthornGall#2-DSC08924HawthornGall#3onLeaf-DSC08937

Heteroecious: noun/adjective, parasites (esp rust fungi) undergoing different stages of the life cycle on different host species. Compare Autoecious.