Suppressive fodder plants as part of an integrated management program for Parthenium hysterophorus L.
Parthenium hysterophorus L. is an alien invasive weed in both Australia and Pakistan infesting rangelands, reducing fodder biomass and causing significant livestock production losses. Previous studies have identified a number of introduced and native fodder species that can suppress the growth of P. hysterophorus in glasshouse trials. These species can also provide an adequate fodder biomass for livestock production. In this study 11 of these fodder species were sown at the recommended rates into P. hysterophorus infested field sites at Injune and Monto, Australia while an additional five species were sown into similar infested field sites at Islamabad and Mardan, in northern Pakistan. Measurements taken on dry shoot biomass production of the fodder species were used to determine their P. hysterophorus growth suppressing ability and fodder biomass production. In Australia, all of the fodder species suppressed the growth of P. hysterophorus, with Setaria incrassata, Cenchrus ciliaris, Clitoria ternatea, Themeda triandra and Astrebla squarrosa (Injune field site), and Chloris gayana, C. ciliaris, Dichanthium sericeum, Clitoria ternatea and Bothriochloa insculpta (Monto field site) all suppressing growth by >62% and producing at least 329 g m-2 of dry fodder biomass. In Pakistan, all of the fodder species suppressed the growth of P. hysterophorus, with Sorghum almum, C. ciliaris and C. gayana suppressing growth by >73% and producing at least 622 g m-2 of dry fodder biomass. Some species such as S. incrassata performed well at just one field site, while others (C. ciliaris and C. gayana) performed well at all the four field sites, indicating that such plants could be considered as part of a new integrated weed management system for P. hysterophorus in both Australia and Pakistan.