Potential of Penicillium crustosum metabolites in controlling parthenium weed.
Parthenium (Parthenium hysterophorus L.) ranks amongst the top ten most devastating weeds. It has spread on a large scale in various regions of Punjab and Khyber Pakhtunkhwa, Pakistan. In an attempt to search alternatives to chemical herbicides for control of this weed, metabolites of a fungal species Penicillium crustosum were evaluated for their herbicidal potential. The fungus was grown in two growth media viz. potato dextrose broth (PDB) and malt extract broth (MEB) for two weeks. After filtration, the culture filtrates from both the media were used in original (100%) as well as diluted (50%) forms. The experiment was carried out in 9-cm Petri plates, having 25 parthenium seeds in each plate. The effect of metabolites was assessed on germination and seedling growth. PDB metabolites proved more inhibitory against various studied parameters than the metabolites prepared in MEB. There was 62%, 88%, 91% and 93% suppression in germination, shoot length, root length and seedling dry biomass over control due to original metabolites prepared in PDB as compared to 33%, 74%, 94% and 81% reduction in these parameters, respectively, due to MEB metabolites.