Amna Javaid

Management of parthenium weed by extracts and residue of wheat

This study was carried out to investigate the prospects of using methanolic extracts and residue of wheat ( Triticum aestivum L.) for the management of parthenium ( Parthenium hysterophorus L.), one of the world’s worst weeds. In a laboratory bioassay, the effect of methanol extracts of 1, 2, 3, 4 and 5% (w/v) concentrations of four wheat varieties namely: AS 2002, Inqalab 91, Ufaq and Uqab was studied against the germination and seedling growth of parthenium. Extracts of all the four wheat varieties suppressed germination as well as root and shoot growth of the seedlings. In soil amendment bioassay, dried and chopped wheat straw of the four test wheat varieties was thoroughly mixed in pot soil at 0.5, 1.0 and 1.5% (w/w). Pots were irrigated with tap water and left for one week followed by sowing of seeds in these pots. The effect of residue incorporation of all the wheat cultivars was insignificant on germination of parthenium seeds. However, all the residue incorporation treatments significantly reduced the survival percentage of the parthenium seedlings. Root and shoot growth in terms of length, and fresh and dry biomass were also significantly suppressed by residues of all the four test wheat cultivars. This study concludes that parthenium weed can effectively be managed by amending the soil with wheat residue. Key words : Non-chemical weed control, parthenium, wheat residue.

Herbicidal Potential of Drechslera spp. Culture Filtrates Against Parthenium hysterophorus L.

Herbicidal activity of culture filtrates of four Drechslera spp., namely D. australiensis (Bugnic.) Subram. & B.L. Jain, D. biseptata (Sacc. & Roum.) M.J. Richardson & E.M. Fraser, D. hawaiiensis Bugnic. ex M.B. Ellis, and D. holmii (Luttr.) Subram. & P.C. Jain, prepared in malt extract broth was investigated against parthenium weed ( Parthenium hysterophorus L.) in both laboratory bioassays and pots. In laboratory bioassays, the effect of original (100%) and diluted (50%) culture filtrates of the four Drechslera spp. was studied on parthenium germination and seedling growth in 90 mm diameter Petri plates. Original culture filtrate of all the four Drechslera species significantly reduced germination, shoot length, shoot fresh biomass, root length, and root fresh biomass of parthenium seedlings by 43 to 77%, 77 to 82%, 69 to 82%, 90 to 92%, and 67 to 83%, respectively, as compared to the control. In pot trials, foliar application of original fungal culture filtrates was carried out on 1-wk and 2-wk old parthenium seedlings. Culture filtrates of all the four Drechslera spp., except D. holmii, markedly reduced parthenium shoot dry weight. Two-week-old plants were more susceptible to foliar spray than the 1-wk old plants. There was a 13 to 55% and 28 to 65% reduction in shoot dry weight of 1-wk and 2-wk old parthenium plants, respectively, due to culture filtrates of various Drechslera spp. The present study concludes that Drechslera spp. culture filtrates can be used as alternative herbicides for parthenium weed management.