BY IVAN CARTER, VSTWP EXTENSION OFFICER, 2017.
Damien Smith is an experienced farmer on a 100ha farmlet south of Gisborne, which has fertile dark loam soils, lending itself to productive small-scale farming. He had observed many droughts, floods and good periods of farming conditions for breeding his Alpacas and livestock. He can recall many species of invasive plants emerging into the area, including the first outbreak of gorse in the area, but had never noticed serrated tussock in the area until the last decade.
Serrated tussock was first observed after some fodder was brought into the farm to feed the livestock over a decade ago. At first Damien was sure the serrated tussock was a native grass and was happy for it to colonize the bear sections of the paddock. He was aware of the invasiveness of serrated tussock and after doing some reading was still unsure if he had the noxious weed. Concerned that he may have serrated tussock he began spraying with a registered herbicide after a few years.
Photo 1: Serrated tussock grazed low during early Spring, making it very difficult to spot
In the winter of 2016 the Victorian Serrated Tussock Working Party (VSTWP) held a serrated tussock information day for their Gisborne Stage 2 Target area. Damien could not attend the information day but after a VSTWP Extension Officer visited the property an inspection was arranged in Spring 2016.
Damien was keen to learn the finer points in how to identify serrated tussock and was thirty percent through spraying the three hectares of serrated tussock in his middle paddock. During the inspection two further areas of tussock were discovered, which were added to the treatment regime. The infestation covered approximately 20% of the farmlet, with some areas being very dense and taking hold of the productive areas. It was concluded that the Alpaca’s had assisted with the spread to the multiple paddocks, with their movement across the property during seeding periods and their feeding amongst the mature plants.
The good work that Damien had commenced with his spraying regime was complimented with the addition of holding paddocks and feed-out areas, as well as the introduction of selective herbicide to ensure no off-target damage. The VSTWP wrote a management plan for the property that suggested spraying with the selective herbicide fluproponate and sowing down with perennial pastures. The medium term plan was to continue treatment of all serrated tussock prior to seeding and ensure all sourced fodder was free of weeds and contained to the feeding area. This allows monitored for weeds and new plants on a regular basis.
There are a few take home messages. It is important to identify serrated tussock early, and control small infestations before they spread. Fodder and feed can contain all kinds of invasive plants, especially if sought from all over the state during drought periods. The other important lesson is that livestock can assist in the spread of invasive plants, including serrated tussock, from infested paddocks to a clean paddocks. It is vital that livestock are quarantined from infested areas during seeding periods and that all plants are treated prior to seeding. Longer term management of the farmlet involves monitoring and manual removal of plants every spring and autumn, and maintaining competitive ground cover and pasture improvement.
All plants were treated in 2016, a good effort considering the large number of plants. The farmlet will be at a stage in 2017 where stock can be introduced and pasture can be re-sown in overgrazed areas. Damien said “I thought it might have been serrated tussock, but I was onto it too late and it spread rapidly before we were able to slow its invasiveness”.
Photo 2: Scattered plants treated using herbicide. If left untreated, these plants can spread quickly across a landscape.