Journal of Research in Weed Science

Abstract Seed germination of some crops (Brassica campestris and Triticum aestivum) and weed seeds (Ageratum conyzoides, Bidens pilosa, Cyperus rotundus and Galinsoga parviflora) was studied under different environmental conditions like moisture (concentrations 3, 6, 9, 12, 15ml), temperature (5, 10, 15, 20 and 25˚C), pH (value 4, 5, 6, 7, 8 and 9) and light (normal, red, yellow, blue, green and dark color). For the crops too much lower or higher moisture was not favorable for germination and growth. Experiments under different moisture conditions showed that C. rotundus and G. parviflora do not require more moisture to germinate and grow. Seed germination of both crops enhanced insignificantly at 15 to 20˚C treatments. Seed germination of all weed seeds was insignificantly high at 10 to 15˚C. The percentage of seed germination of both crops increased significantly in normal and green light. Seed germination of A. conyzoides, C. rotundus and G. parviflora was insignificantly different in normal, red, yellow and green light. Germination of all weed seeds was completely inhibited by blue and dark light. The shoot and root length of weed A. conyzoides was found to be significantly high (P=0.05) in yellow light treatment, but in B. pilosa, it was high in red and green light. Similarly in C. rotundus, shoot and root length were high in normal light but in of G. parviflora it was high in green light treatment. Seed germination and seedling growth were higher in pH5-7 in most cases.

Abstract The present study was carried out to evaluate the efficacy of botanical extracts on the management of Parthenium hysterophorus through laboratory experiments. These experiments were carried out at Department of Agronomy, Agricultural College and Research Institute, Madurai during 2013-15. The efficacy of twenty botanicals viz., Abutilon indicum, Amaranthus spinosus, Amaranthus viridis, Azadirachta indica, Calotropis gigantea, Croton bonplandianum, Cynodon dactylon, Cyperus rotundus, Datura metel, Echinochloa crusgalli, Helianthus annuus, Lawsonia inermis, Mangifera indica, Prosopis juliflora, Solanum nigrum, Sorghum bicolor, Sorghum halepense, Tagetes erectus, Tamarindus indica, Tephrosia purpurea were tried at different concentrations under laboratory bioassay. The study reveal that the per cent germination, seedling length, seedling vigor index and seedling biomass of P.hysterophorus was reduced significantly due to application of all botanicals, however the effect was more pronounced with botanicals extract  in the order of Datura metel, Mangifera indica, Azadirachta indica, Tagetes erectus, Helianthus annuus and Sorghum bicolor both at 50 and 75 % concentrations. Increased concentration (50 and 75 %) was pronounced more detrimental effects on per cent germination and seedling growth parameters of P.hysterophorus.