ASSOCIATION OF ARABIS MOSAIC VIRUS WITH HOP CHLOROTIC DISEASE

Hop chlorotic disease was first described in England in 1927 (Salmon and Ware, 1930; 1932a; 1932b; 1935) and has since been seen rarely. In 1983 a patch of 40 diseased plants occurred in a large area of hops cv. Bramling Cross planted in Kent in 1967. The distribution of infected plants was closely correlated with infection by arabis mosaic virus (AMV), both in 1983 and in 1984 when three more diseased plants occurred. Furthermore, the disease appeared in five of 43 seedlings raised from the seed of affected plants: all five were infected with AMV while the remaining 38 plants were not.

Isolates of AMV from hop plants with chlorotic disease were similar to other isolates from hop both serologically and in symptoms induced in Chenopodium quinoa.

These findings show that chlorotic disease has features in common with bare bine, split leaf blotch and nettlehead which are also hop diseases caused by or associated with AMV (Thresh et al., 1972). Satellite-like RNA is associated with nettlehead (Davies and Clark, 1983) but none has been found in hop plants with chlorotic disease.