BACTERIAL STREAK AND BULB ROT OF SWEET ONION - II - EPIPHYTIC SURVIVAL OF PSEUDOMONAS-VIRIDIFLAVA IN ASSOCIATION WITH MULTIPLE WEED HOSTS

A semiselective agar medium (T-5) was used to sample environment and p lant material as a habitat for Pseudomonas viridiflava. Soil, irrigati on water, soybean foliage, and foliage from various weeds in an onion- growing area were assayed over a 5-year period. P. viridiflava was rec overed only as an epiphytic resident from weed species that included c utleaf evening primrose, dandelion, common fumitory, purple cudweed, s piny sowthistle, Virginia pepperweed, and wild radish. The bacterium a pparently overseasons in association with these weeds, because its pre sence was detected prior to, as well as during, the onion-growing seas on. Preliminary tests indicated that weed control may suppress bacteri al streak and bulb rot levels.