Consort black currant

Eastern white pine and causes leaf spots and leaf loss in currant and gooseberry plants. WPBR can be found throughout Minnesota but is most common in northern and eastern Minnesota where cool moist conditions in consort black currant summer favor infection. WPBR needs to infect both a currant or gooseberry plant and a white pine to complete its life cycle.

Diseased pine branches should be pruned out of the tree before the infection comes within 4 inches of the main trunk. Disease resistant currant and gooseberry bushes are available. All needles on one or more individual branches first turn yellow, then rusty red. The branch with the dead needles will have a canker which is a swollen area with discolored and cracked bark. Cankers on the main trunk are oval or diamond-shaped and often have a dead branch in the center.

Sticky, clear-to-white sap oozes from the canker and drips from the infected branch or runs down the trunk. In spring, white-to-yellow blisters form at the edge of the canker and release powdery orange spores. Gummy, orange droplets containing spores may be seen along the canker in summer. Angular, yellow leaf spots that are contained by leaf veins can be seen on the upper leaf surface. Raised, orange pustules can be seen on the underside of the leaf spot. By late summer or early fall, orange or brown, hair-like tendrils form amongst the orange pustules on the underside of the leaf.