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Poster: Biology & Disease Mgmt: Bacteriology


Characterization and Management of Ralstonia solanacearum Causing Bacterial Wilt of Tomato in Louisiana
A. JIMENEZ MADRID (1), A. Jimenez (1), M. Lewis Ivey (1) (1) Louisiana State University, U.S.A.

Ralstonia solanacearum (Rs), the causal agent of bacterial wilt of tomato can cause severe economic losses to tomato growers in Louisiana. Traditional management tactics such as soil fumigation and crop rotation are ineffective. Resistant cultivars lack durability and have undesirable horticultural traits. For these reasons, many producers in Louisiana have abandoned their fields for tomato production. Although R. solanacearum is endemic in Louisiana, pathogen populations have not been characterized. Tomato samples with bacterial wilt symptoms were collected from three parishes in 2015. Bacterial wilt was confirmed using commercial Rs-specific immunostrips and the bacterial streaming test. Fifteen isolates were recovered from four fields and a greenhouse and all belonged to phylotype II. Thirty-three percent of the strains were characterized as biovar 1 and 20% as biovar 3. The remaining strains did not conform to a published biovar pattern. None of the isolates were Race 3 biovar 2 based on results from R3bv2-specific PCR. Grafting with resistant rootstock varieties is being explored as a sustainable management strategy. Louisiana tomato growers were surveyed for their willingness to use grafted plants with Rs resistance. Sixty-six percent of the growers indicated that they would be willing to use Rs-resistant grafted plants but ranked not knowing how to graft and the cost of grafted plants as the top two factors that would hinder their adoption of this strategy.