Apple mosaic virus

Pictures:  Yellow banding (1),    yellow banding (2),    ring spot,   oak leaf pattern    virus particles

Apple mosaic virus (ApMV; the genus; Ilarvirus; the family Bromoviridae) is one of the most important pathogens on hazelnut. ApMV infection in hazelnut has been reported in many countries, such as in Italy, France, Spain, the UK, the USA and Turkey.
Damage:
ApMV does not significantly affect the commercial characteristics of nuts (proportion of blank nuts, nuts with brown spot in kernel cavity or the fatty acids composition) in infected trees of Spanish cultivar ‘Negret’; however, it could cause an important yield reduction as a consequence of a decrease in nut number.
Natural Host Range:
ApMV can experimentally or naturally infect over 65 species in 19 different families. Natural hosts of ApMV include apple, rose, hazelnut, horse chestnut, raspberry, birch, hops, stone fruits, blackberry and strawberry.
Description
Virus particles are isometric 25 and 29 nm in diameter (and probably a third size). Virus particles contain 16 % nucleic acid and 84 % protein. ApMV has three genomic RNA (RNA 1, RNA 2 and RNA 3) and one sub-genomic RNA (RNA 4 species).
Transmission
Natural vector of ApMV is unknown. Virus is transmitted by mechanical inoculation and root grafting. It is also transmitted by seed and pollen of hazelnut. ApMV is usually transmitted with difficulty by mechanical inoculation of sap from woody plants to several herbaceous species in vitro.

(Prepared by Dr.Miray Arlý Sokmen, Ondokuz Mayýs Uni. Dept.of Plant Pathology, Samsun, Turkey.)