SOIL INCORPORATION OF CRUCIFEROUS PLANT RESIDUES AS A CONTROL STRATEGY FOR PANTOEA ANANATIS COLONIZATION OF ONION SEEDLINGS.

The effect of cruciferous plant residues (milled seeds of mustard and rapeseed meals) on the colonization of onion (Allium cepa L.) seedling roots by Pantoea ananatis was investigated. These materials incorporated into a peat medium at a dosage of 0.5% (w/v) decreased the colonization of onion seedlings by the pathogenic bacterium. These materials showed also a positive effect on the growth of onion seedlings, increasing fresh plant weight by three to fivefolds. Moreover, the total microorganism population was higher in the peat medium additioned with plant materials than in the control. An increase in the total number of bacteria and actinomycetes was observed, which may have caused a higher suppressiveness of the peat medium towards P. ananatis. On the other hand, the biological active compounds released from crucifers may have inhibited the growth of the bacterium. [ABSTRACT FROM AUTHOR]