Control of Pseudomonas amygdali pv. loropetali on Metal, Wood, and Loropetalum chinense Stem Surfaces

Clorox Germicidal Bleach, Cuproxat, Green-Shield II, KleenGrow, Virkon S, and ZeroTol 2.0 were evaluated for their ability to inactivate Pseudomonas amygdali pv. loropetali on stainless steel (SS), pressure-treated wood (PtW), and loropetalum stem sections. Clorox at 11% product and Virkon S at 1.0% product eliminated P. amygdali pv. loropetali on SS surfaces and nearly eliminated it on PtW surfaces. Green-Shield II at 0.5% product and KleenGrow at 0.8% product nearly eliminated the bacterium on SS, while causing a significant reduction without elimination on PtW. Cuproxat and ZeroTol 2.0 were not effective against this bacterium in these applications. Clorox and KleenGrow were evaluated further for their ability to kill P. amygdali pv. loropetali on loropetalum stems, which was used as a preliminary surrogate for vegetative stem cuttings. Only Clorox eliminated bacteria from stem surfaces, but the bacterial inoculum level appeared to affect efficacy. Several disinfestants are commercially available that kill P. amygdali pv. loropetali on production surfaces.