Weed suppressing ability of parthenin a sesquiterpene lactone from <i>Parthenium hysterophorus</i>

To find alternate chemicals with novel mode of action allelochemicals which are natural plant products are being investigated This study was undertaken to explore the effect of parthenin (chemically a sesquiterpene lactone from Parthenium hysterophorus L) on two weed species viz Amaranthus viridis and Chenopodium murale In a laboratory bioassay germination seedling growth and dry weight accumulation of the weeds were significantly reduced by treating with parthenin The chlorophyll content and the respiratory activity were also significantly affected in the treated plants The study concluded that phytotoxicity of parthenin could be useful as a natural herbicide for future weed management programmes</jats:p

Fungicidal effect of volatile oils from &lt;i&gt;Eucalyptus citriodora&lt;/i&gt; and its major constituent citronellal

A study was undertaken to explore the effect of volatile oils from Eucalyptus citriodora and its major constituent citronellal against two wellknown rice pathogens Rhizoctonia solani and Helminthosporium oryzae The radial growth and dry weight of both the test fungi were drastically reduced in response to the volatile oils A complete inhibition of R solani and H oryzae was observed at 10 and 20 ppm respectively Citronellal alone was found to be more effective than eucalypt oils Based on the study it was concluded that eucalypt volatile oils have potential for the suppression of phytopathogenic fungi</jats:p