Efficacy of aqueous plant extracts on bacterial soft rot of radish

Aqueous leaf extracts of marigold (Tagetes erecta), eucalyptus (Eucalyptus citriodora), aonla (Emblica officinalis), kala dhatura fruit (Datura metel), castor (Ricinus communis) and kumkum (Bixa orellena) were most effective in checking the growth of Pectobacterium carotovorum subsp. carotovorum in the filter paper disc assay. Effectiveness of all these extracts varied at different dilutions. Undiluted extracts (100%) of amaltas (Cassia fistula), ashwagandha (Withania somnifera), garlic cloves (Allium sativum), jeevanputra (Jeevanputra roxburghii) and neem (Azadirachta indica) exhibited moderate activity against the test pathogen. Increase in soaking period of radish in the plant extract reduced the effectiveness of the extracts in the PWL assay. However, soaking of radish for 6 hrs. in aqueous extracts of eucalyptus and marigold arrested the development of soft rot of radish both in vitro (PWL assay) and pot culture study. Steckling dip treatment of radish roots in aqueous extracts of Tagetes erecta and Eucalyptus citriodora (10%) reduced the soft rot until 60 DAT.