For this reporting period, different formulations of Mg-hydroxide or Zn-hydroxide loaded with Cu-chelates were successfully synthesized using sol-gel chemistry. The total metal content is 40,000 ppm (wt/V) including up to 50% of Cu-chelates (equivalent to 20000 ppm of metallic Cu; the A.I.): (1) Cu: Mg (10%: 90%, MM10C90M), (2) Cu: Mg (25%: 75%, MM25C75M), (3) Cu: Mg (50%:50%, MM50C50M), (4) Cu: Zn (5%:95%, MM5C95Z), (5) Cu: Zn (10%:80%, MM10C90Z), (6) Cu: Zn (25%:75%, MM25C75Z). The stability of each formula was observed for the duration of 48 h post-synthesis. Most formulations (except for MM50C50M and MM25C75Z) formed a stable colloid as no phase separation was observed. Hydrodynamic diameter of the colloidal solution was estimated using Dynamic Light Scattering (DLS) technique. The hydrodynamic size for MM50C50M, MM25C75Z and MM25C75M was estimated to be around 880 nm, 580 nm and 450 nm, respectively, suggesting aggregation of primary particles. MM25C75M particle size was comparable to MM10C90C size. DLS particle size of MM5C95Z and MM10C90Z could not be reliably estimated due to low scattering intensity (less than 10kcps, below the detection limit). This suggests that MM5C95Z and MM10C90Z formulations might contain highly-dispersible ultra-small size particles. Further study using electron microscopy is needed to confirm primary particle size. Phytotoxicity testing was conducted using a plant growth chamber (Panasonic model # MLR 352H, temperature cycle was set for summer conditions, T > 80oF, RH 60-80%). Ornamental vinca plant was used as a model system due to their high susceptibility for metals. Three different foliar application rates (300, 500 and 900 ppm wt/V of total metal content, similar to field application rate) were tested. Phytotoxicity symptoms were evaluated after 3 days of incubation based on visual observation as described in our previous paper (Plant Disease 2016, 100(12), 2442-2447). All multi-metal treatments showed reduced plant leaf damage at all tested concentrations when compared to copper alone. Future reports will include phytotoxicity and antimicrobial efficacy results.�