Relationship between rust mitesCalepitrimerus vitis(Nalepa), bud mitesColomerus vitis(Pagenstecher) (Acari: Eriophyidae) and short shootsyndrome in Oregon vineyards

Short Shoot Syndrome (SSS) causes severe crop losses in Oregon vineyards due to bunch necrosis during the early part of the season. Other symptoms include malformed leaves, unusually short and angled shoots, scar tissue and bronzed leaves close to harvest time. This work shows that SSS found in Oregon vineyards is closely associated with grape leaf rust mite, Calepitrimerus vitis (Nalepa) infestations. Very few bud mites, Colomerus vitis (Pagenstecher), were found in the vineyards during the current year and no relationship could be found between SSS symptoms and this species. During winter, rust mites are dormant and no evidence of direct bud damage from rust mites was found inside undeveloped buds. Tissue damage from mites was first observed between bud break and the two-leaf stage in mite infested vineyards. Rust mite colonies were found under outer bud scales and bark of canes close to the buds. Crop losses as high as 23.7% were directly linked to rust mite infestations and SSS from several vineyards sampled in Oregon.