First report of tomato pith necrosis (Pseudomonas corrugata) on tomato (Solanum lycopersicum) in Washington.

摘要

Tomato pith necrosis was observed on 2.7% of tomatoes grown in rows covered with black polyethylene, various biodegradable plastics, and an experimental spunbond poly(lactic) acid agricultural mulch in high tunnel and open field experimental plots, in western Washington (USA) in 2011. Symptoms developed on 3-month-old plants and progressed acropetally until night temperatures dropped to 10 degrees C. Affected plants had chlorotic leaves, produced adventitious roots, and pith tissue was brown and either corrugated or rotted. Similar symptoms were observed again in 2012 on 2.0% of plants, but only in experimental plots with black polyethylene mulch. Based on biochemical, physiological, molecular investigations (PCR assay) and pathogenicity tests, the causal agent was identified as P. corrugata. This is thought to be the first documented report of tomato pith necrosis in Washington. Pith necrosis has been reported previously in high tunnel tomato production, where excess nitrogen fertilization occurs with cool evening temperatures, and when plastic mulch is utilized. In the cool climate of western Washington, successful tomato production requires the use of agricultural mulches and covers that trap heat. Since P. corrugata has been isolated from soil and the tomato seeds of inoculated plants, local growers attempting to manage pith necrosis need to select tomato seed lots carefully and avoid applying excess nitrogen, especially when using plastic mulch.Digital Object Identifier http://dx.doi.org/10.1094/PDIS-03-13-0265-PDN