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United States Department of Agriculture

Agricultural Research Service

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

item Bull, Carolee
item Koike, Steven - UC, COOP. EXT.

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 21, 2005
Publication Date: November 21, 2005
Citation: Bull, C.T., Koike, S.T. 2005. Evaluating the efficacy of commercial products for management of bacterial leaf spot on lettuce. Online. Plant Health Progress doi:10.1094/PHP-2005-1121-01-RS.

Interpretive Summary: A mixture of a copper based compound and a biological control agent reduced the incidence or severity of bacterial leaf spot on lettuce in 4 out of 6 experiments conducted over a three year period. In some of these experiments disease incidence and severity did not differ on plants to which the mixture was applied as compared to plants to which the individual compounds were applied. Occasionally, the individual components of the mixture significantly reduced disease incidence or severity when compared to the untreated controls.

Technical Abstract: The efficacy of Serenade, Maneb, and Cuprofix as well as mixtures of Serenade and Maneb with Cuprofix were evaluated for efficacy in reducing the 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 half of the experiments. Treatment with the Maneb and Cuprofix resulted in significantly less disease in one experiment and reduced disease severity in an additional experiment. These results indicate that a mixture of Serenade and Cuprofix may be a useful addition to an integrated bacterial leaf spot disease management strategy.

Last Modified: 4/21/2015