Identification, Distribution and Vector Biology of Brome Mosaic Virus of Wheat in Alabama

Abstract

Wheat leaves were collected from different counties in Alabama. The collected wheat leaves were tested for the presence of Brome mosaic virus (BMV) using direct double antibody sandwich ELISA. BMV was identified from Escambia, Mobile, Elmore, Autauga, Dallas, Henry, Macon, Baldwin, Dekalb and Limestone counties suggesting that this virus was becoming established throughout the state. Weeds growing in the vicinity of the wheat fields were collected at E.V.Smith Research Center (EVSRC) in Shorter, AL and Gulf Coast Research and Extension Center (GCREC) in Fairhope, AL during April and May of 2004 and 2005. Oenothera laciniata (Evening Primrose) was the only weed species that tested positive for BMV. Soil samples were collected from one wheat variety trial at the EVSRC two times per month from October to May and at other fields in different counties throughout the state monthly during the wheat growing season. Nematodes were extracted by sugar flotation and identified. Even though plant parasitic nematodes were detected in all samples, no Xiphinema spp. were found in relation to any wheat field. However, Xiphinema sp. was found in an adjacent peanut field at EVSRC. Therefore, in Alabama, Xiphinema spp. were neither associated with nor likely to be the vector of BMV. Altica foliaceae, flea beetles were collected from wheat and O. laciniata plants at EVSRC and GCREC during April and May of 2005. The beetles were allowed to feed simultaneously on BMV (Oklahoma strain) infected wheat plants in one pot and uninfected wheat plants in three other pots in an insect cage in the green house. The flea beetles were able to transmit the virus from infected plants to uninfected plants indicating the vector behavior of the insects. The flea beetles collected were mostly associated with O. laciniata, a weed commonly found around the wheat fields. Both the O. laciniata and Altica foliaceae tested positive by ELISA for the virus suggesting that the flea beetles are a vector for BMV in Alabama, and might be involved in transmitting the virus from O. laciniata to wheat fields.