Evaluating the Efficacy of Commercial Products for Management of Bacterial Leaf Spot on Lettuce

Abstract

The efficacy of Serenade, Maneb, Cuprofix, and mixtures of these products were evaluated for efficacy in reducing disease incidence and severity of bacterial leaf spot of lettuce caused by Xanthomonas campestris pv. vitians in six trials at two locations between 2001 and 2003. Additionally, Messenger, elemental copper, Quadris, and Actigard were evaluated in at least two of these trials. Mixtures of Serenade and Cuprofix reduced disease incidence in three of six experiments and reduced disease severity in a fourth experiment. Treatment with the Maneb and Cuprofix mixture was less effective but resulted in significantly less disease and lower severity in single experiments. These results indicate that a mixture of Serenade and Cuprofix may be a useful addition to an integrated bacterial leaf spot disease management strategy but this treatment may be too variable to justify it as a stand-alone treatment. Accepted for publication 21 October 2005. Published 21 November 2005.

Characterization and Performance of 16 New Inbred Lines of Lettuce

“…In the first of three experiments, three Xcv strains (BS339, BS340, and BS347) were used as inoculum; however, after determining that strain BS347 was more virulent than the other strains (data not shown), only BS347 was used in the second and third experiments. All of these strains were isolated from lettuce plants in California (Barak and Gilbertson, 2003;Bull and Koike, 2005). Xcv suspensions of 1 • 10 8 colony-forming units/mL were prepared according to Bull et al (2007).…”

Genetic Diversity of Lettuce for Resistance to Bacterial Leaf Spot Caused by Xanthomonas campestris pv. vitians

“…Bacterial leaf spot of lettuce, caused by Xanthomonas campestris pv. vitians, is an important disease of lettuce in California (2,3). The disease is sporadic but problematic throughout North America (4,7,8,10).…”

“…Chemical applications, including those suitable for certified organic production, may reduce bacterial leaf spot and fit into a comprehensive management strategy (3,4,6,8). However, the effectiveness of the chemicals depends on their application prior to symptom development.…”

Acibenzolar-S-methyl induces lettuce resistance against Xanthomonas campestris pv. vitians

“…Twelve days after inoculation, disease severity was evaluated by rating the most severely damaged area of all the treated plants on a scale of 0 to 5 (plants with no visible symptoms = 0; a few individual lesions = 1; many individual lesions = 2; small patches of coalesced lesions = 3; medium sized patches of coalesced lesions = 4; and large patches of coalesced lesions = 5) and calculated with Tousend-hoberger equation (Bull and Koike, 2005). The experiments were arranged in a completely randomized design with there replications.…”