Our project to evaluate the efficacy of the herbicide, Fusilade, on Large Quaking Grass and its impact on the native flora, which was funded through the State Governments “Communities for Nature Fund”, is now completed.
Our Monday morning weeders met Tim D’Ombrain, from Biodiversity Services, onsite in October, after he had reviewed the herbicide trial. Tim had sprayed Fusilade Forte in early July, when Large Quaking Grass was at the 2–5 leaf stage, in a randomised, replicated trial. Fusilade is a grass specific herbicide that will not affect native grasses when used in winter, at the time the grasses are not growing. Neither does it affect lilies or orchids. We had set up 200 m2 plots, which Tim sprayed with the following concentrations of Fusilade Forte, 6 ml/5L, 4 ml/5L and 2 ml/5L, and one left unsprayed for a control plot.
In all, there were the six treated plots, which had a density of Large Quaking Grass of less than one plant per square metre, after the growing period. The density of Large Quaking Grass in untreated areas of the reserve varied between 0 to 50 plants per square metre, with an average of greater than 5 plants per square metre. There was no obvious difference in the number of Large Quaking Grass plants in the plots that had been treated with the three different rates of Fusilade Forte. Peter Matthews, an Angair member, has taken photographs from the centre of each plot, and provided further evidence that there was no difference in the number of flower heads of Large Quaking Grass, irrespective of the 3 treatments.
It should be noted that it was not a good year for annual grasses, because of much lower than average spring rains. The bulk of Large Quaking Grass in the reserve is much less than during the last 2 years. Also, the grass tended to be lower and smaller as well. Despite the dry spring, the results of the trial were still considered conclusive. Each July, the entire reserve and the rear drain easement could be sprayed at a concentration of 2 ml per 5 L over an area of 200 m2. This should dramatically reduce the Large Quaking Grass problem over the next few years, as the seed of the annual grass is short lived.