APS Homepage

Oral: Emerging Nano Materials for Disease Management and Insights from Findings in Nano-based Diagnostics


Advanced copper and zinc nanomaterials for management of bacterial canker of citrus.
E. JOHNSON (1), M. Myers (2), K. Gerberich (1), S. Santra (3), J. Graham (1) (1) University of Florida, U.S.A.; (2) University of Florida, U.S.A.; (3) University of Central Florida, U.S.A.

Bacterial plant pathogens are notoriously difficult to control. Copper is effective as a surface protective film but does not move systemically without risk of phytotoxicity. Best management of copper is spray application to fruit and foliage, however, optimum coverage along with frequent reapplication is required because the protective film is broken as tissues expand. Dependence on copper has led to bacterial resistance and accumulation of phytotoxic levels of copper in agroecosystems. Due to these drawbacks, new bactericides with alternative modes of action are needed to replace or rotate with copper. Nanomaterials, if properly designed with agricultural economics in mind, can provide new modes of action with copper equivalent or better efficacy. Nanomaterials also provide the possibility of systemic activity depending on particle size and composition. Using citrus canker, caused by Xanthomonas citri subsp. citri, as a model system, multiple new bactericides have been validated as equivalent or better than traditional copper formulations for canker control. At least three modes of action have demonstrated efficacy including a nano-copper formulation, fixed quaternary ammonium, and both particle and film forming zinc nanomaterials. Development of multiple modes of action offers the potential for resistance management of bacterial targets in control of local lesion diseases and potential for systemic activity.