|Wintermantel, William - Bill|
Submitted to: The Pink Sheet Strawberry News Bulletin
Publication Type: Other
Publication Acceptance Date: 7/1/2004
Publication Date: 7/20/2004
Citation: Wintermantel, W.M., Tzanetakis, I.E., Martin, R.R. 2004. Management of whitefly transmitted viruses in strawberry. The Pink Sheet Strawberry News Bulletin.
Technical Abstract: Within the last few years, the greenhouse whitefly (GHWF), Trialeurodes vaporariorum, has been emerging as a serious threat to field agriculture in California's coastal areas. Although whiteflies themselves can cause significant crop damage, GHWF-vectored viruses can cause losses that are much more economically damaging than those resulting from vector feeding alone. Two GHWF vectored viruses affect strawberry, Beet pseudo yellows virus (BPYV) and Strawberry pallidosis associated virus (SPaV). In regions where the GHWF occurs, both BPYV and SPaV are part of a virus complex that causes decline of strawberry, a disease reported in numerous states and Canada. Until 2003, SPaV and BPYV were not recognized as major viruses by the strawberry industry. However, recent studies indicate that these two viruses are a major component of strawberry decline in the eastern United States and California. The disease is the result of a virus complex that includes BPYV and/or SPaV with any of a number of different strawberry-infecting viruses. Symptoms of this decline are often mistaken for physiological or nutritional disorders, pesticide phytotoxicity, or other diseases. The virus complex causes the development of a red color in older leaves, leaf distortion, vein and petiole reddening, stunted roots, and failed plant development. Strawberry pallidosis associated virus in single infections has been reported to reduce runners and root growth in 'Northwest' strawberry by 15-20% but on its own does not cause the severe decline that has been observed in recent years in California strawberry fields. During the summer of 2003, strawberries in coastal areas of California were damaged severely by a virus induced decline, with some fields exhibiting as high as 75 percent infection with either SPaV or BPYV, accompanied by high incidence of GHWF.