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POSTERS: Chemical control

Evaluation of antimicrobial effects and plant uptake of novel antimicrobial formulation MS3T to control surface and systemic pathogens in citrus.
Hajeewaka Mendis - University of Central Florida. Maria Campos- University of Central Florida, Ali Ozcan- University of Central Florida, Swadeshmukul Santra- University of Central Florida

MS3T (multifunctional surface/sub-surface/systemic therapeutic) is a novel plant nutrient-based antimicrobial formulation developed for controlling citrus bacterial pathogens ‘Candidatus Liberibacter asiaticus’ (CLas) and Xanthomonas citri (Xc). MS3T components quaternary ammonia (DDAC) and Zn chelate (TSOL) are designed to control plant surface pathogens and systemic pathogens respectively. This study investigated the antimicrobial effects of MS3T and its components in vitro on CLas and Xc surrogate X. alfalfae (Xa) and E. coli (Ec). Ec and Xa were grown in LB and NB with serial dilutions of MS3T, Zn(NO3)2 and DDAC to determine Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Systemic movement of TSOL in citrus plants after foliar application was evaluated using atomic absorption spectroscopy (AAS). Phytotoxicity of MS3T was evaluated in tomato seedlings as a model system since citrus seedlings are less susceptible to phytotoxicity. The MIC of Zn(NO3)2 and DDAC against Xa is 16ppm and 0.5ppm whereas MBC is 32ppm and 1ppm respectively. The MIC of MS3T for Xa is 1.5ppm and 6ppm DDAC and Zn. The MIC of Zn(NO3)2 and DDAC for Ec is 128ppm and 4ppm whereas MBC is 512ppm and 4ppm respectively. The MIC of MS3T for Ec is 6ppm and 24ppm DDAC and Zn. No phytotoxicity was observed in tomato seedlings after MS3T foliar application. AAS analysis revealed that TSOL is uptaken by citrus leaves and transported to roots through phloem.