Development of a sanitizing agent for use on field equipment to reduce the spread of olive knot in mechanized olive production in California
K. NGUYEN (1), H. Forster (1), J. Adaskaveg (1). (1) Department of Plant Pathology and Microbiology, University of California Riverside, Riverside, CA, U.S.A.
New methods in olive production such as high-density planting, mechanical harvesting, and automated hedging have increased the risk of spreading <i>Pseudomonas savastanoi </i>pv.<i> savastanoi </i>(Psv), the causal agent of olive knot. Routine disinfection of field equipment with sanitizers could reduce spread of Psv to healthy trees by preventing field equipment from becoming inoculum sources. Oxidizers such as chlorine or peroxyacetic acid are not used due to their corrosive properties and ineffectiveness in the presence of organic material. We conducted in vitro direct contact (DC) toxicity and hard surface disinfection assays (HSD) to evaluate the efficacy of sanitizers. A quaternary ammonium compound (i. e., Deccosan 321 – D321) was tested due to its potential for registration since it is currently used in Florida for equipment disinfestation for diseases of other crops. In DC assays, D321 at 5 mg/L or 25 mg/L reduced Psv growth by 97.3% or 100%, respectively, when a 1x10<sup>8</sup> CFU/ml suspension of Psv was exposed for 60 sec. In HSD assays where PVC pipes were contaminated with macerated olive tissue containing 1x10<sup>6 </sup>CFU/ml Psv, D321 at the suggested rate of 2000 mg/L reduced bacterial growth by 99.8% in 90 sec, proving it to be highly effective under an organic load. In comparison, chlorine was less effective. Based on these findings, D321 was submitted for registration for use on olives in California and is expecting approval by 2015.
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