PHYTOPHTHORA ROOT ROT OF THE CULTIVATED CRANBERRY IN MASSACHUSETTS (VACCINIUM MACROCARPON AIT.)
During the fall of 1986, Phytophthora cinnamomi (mating type A2) was isolated from discolored underground runners sampled from dying 'Early Black' and 'Howes' cranberry plants in 18 bogs. Each bog typically had large patches of plants which were dead or dying and stressed plants were associated with low/wet spots in the bog. When affected areas were sanded and replanted with new vines, the replacement vines also died. Underground runners lack feeder roots, show discrete lesions and a distinctive olive-brown discoloration. The fungus has now been found in more than 160 separate bogs which encompass nearly 3 000 acres. Control strategies include improving the drainage in affected spots, sanding, applying Ridomil, and fertilizing the peripheral stressed plants. The varieties 'Stevens', 'Franklin', and 'Bergman' have shown some resistance to the disease. The fungus appears to be present only in the affected areas and cannot be isolated from the roots or soils surrounding healthy plants.
Caruso, F.L. (1989). PHYTOPHTHORA ROOT ROT OF THE CULTIVATED CRANBERRY IN MASSACHUSETTS (VACCINIUM MACROCARPON AIT.). Acta Hortic. 241, 307-311