rust of currant. disease on black currant leaves caused by a fungus cronartium ribicola

leaf green plant flower nature tree produce shrub insect branch grass herb invertebrate wildflower food petal rust currant disease black leaves caused fungus cronartium ribicola ribicola cronartium macro blister fungus rust agriculture yellowing dying attack yellow foliage growth environment currant season color garden background pinus strobus ribes nigrum damage fungal infection pine bush protection cure summer shrub host protect green natural nature ill pinus rusty diseases leaf orange symptoms closeup spores plant spots fungal infect underside