Giant Parramatta Grass- No 'Weak Links' Found

the NEWSLETTER of ThelWeed Society of New South Wales Inc ISSN 1325-3689 #8 DECEMBER 1996 Giant Parramatta Grass- No ’Weak Links’ Found ccording to John Betts from NSW-Agriculture at Grafton,. A studies on giant Parramatta grass (Sporobolus indicus var. africanus) at the Universities of New England and Queensland have not revealed any weak links in the life cycle of this particularly troublesome weed that could be readily utilised in its management. - FEATURE ARTICT ,E WEED SOCIETY The seed has a sticky coating when EXECUTIVE ...Giant Parramatta wet and will readily stick to smooth surfaces. Therefore, seed is most John Cameron Grass - No ’Weak (President) likely to spread when the grass is wet Links’ Found .with rainfall or heavy dew. Dan Austin (Vice President) Some viable seed will pass undigested through the gut of cattle. It takes Leon Smith Studies on ’what makes giant Parramat~a (Secretary) about 6-7 days for all the seed to pass grass tick’ and biological control of this through. However, in the field this Alex McLennan weed have been completed in the pail method of dispersal does not appear to (TreasureO year. The studies were funded by the be important as cattle rarely eat the Brian Sindel seed heads. Seed sticking to hides, or Meat Research Corporation and conducted vehicles,, etc.. is a much more likely (Newsletter Editor) by Todd Andrews at the University of New England and Shane Heatherington at means of dispersal~ Mike Barrett the University of Queensland as part of Botany .experts have predicted that Gary Beehag PhD degrees. Jim Dellow giant Parramatta grass will spread to John Betts summarises some of its environmental limits despite all ¯Lawrie Greenup the major findings of both studies as Mike Hood efforts to contain it. They reason that Jane Mallen-Cooper follows. our modem lifestyle, rapid transport Peter Michael and the weed’s dispersal mechanisms Allan Murphy No weak links werd found in the life Robert Plumbe make this inevitable. Val Stubbs cycle of gi~t Parramatta grass. Gordon Tink Giant Parramatta grass is attacked by a : . J0hr~ Toth . In dense infestations seed production fungus called Bipolaris which causes !~-Bob Trouhcd potential can be phenomenal, up to a fake smut disease of the seed head. 750,000 seeds per square metre. Two species of this disease organism Editor:. Brian Sindel infect giant Parramatta grass. Department of Agronomy Large’ soil seed bank reserves were and Soil Science, measured on heavy infestations, up to The general conclusions of the-biological University of New 20,000 seeds per square metre. England, Armidale 2351 control study using the above organisms Ph: (067) 733 747 -were: Fax: (067) 733 238 Email: Projections of seed longevity in the [email protected] soil indicated that Some viable seed the disease occurs too late in the may still be present in soil 10 years season to restrict the greatest seed fall after seeding. Secretary: Leon Smith event; 8 Darwin Drive, Lapstone 2773 Seed germinates best when there is a the plant appears to compensate with ptgfax: (047).393 564 daily fluctuation of soil temperature greater numbers of seed heads between 30°C maximum and 15°C produced when disease infected and minimum. This generally coincides A ~ Weea~ is published greater germination of seed following with October/November and four times per year by lower seed fall; the Weed Society of March/April. New South Wales, the disease organism also attacks PO Box 438 Seed germinates best when it has been Wahroonga 2076. native Sporobolus species (rats tail exposed to light. Implications of the grass). above two points is that bare soil Printed by the University favours germination of giantThe above factors appear to preclude giant of New England Parramatta grass - this is certainly Parramatta grass from biological control at observed in the field. Good ground this stage. ¯ Packaged by the Challenge cover and strong growth of other Foundation in recycled pasture species reduces infestations. plastic page 2 ,,4~/~7¢/ee, #8 DECEMBER 1996 FEATURE ARTICLE Other Work ¯ evaluation of some Swazi grass Other current work on giant Parramatta types that may be useful competitors grass includes: against giant Parramatta grass. getting the best from giant For further information on this Parramatta grass through chemical aggressive grass weed contact: Grafton means using low rates of glyphosate Research Station (Phone 066-420 420). applied with a pressufised wick Cl wiper. This is the "living with it" approach; (Adapted from Beef News, April issue, 1996) selective herbicide application with a pressufised wick wiper, especially to scattered infestations; Serrated Tussock - Biocontrol to Add to Strategy ver the years biological control ~; A management strategy for of serrated tussock (Nassella sedated tussock has recently be O trichotorna) has been discussed developed in Victoria. There are also and abandoned and rediscussed. The committees such as the Upper biggest problem foreseen is its’ closeMurrumbidgee Catchment Coordinating relationship to the native Stipa species Committee and the Cooma-Monaro which form a very important part ofShire who have-.brought together a native pastures. In 1976, Dr M Wells number of groups and organisations to from South Africa visited South Americadevelop a coordinated approach to but found no insects which appeared to serrated tussock control. This will be host specific. In 1988, the South include facilitating regional working Africans again commissioned a surveygroups, coordinating research and with results not looking too promising. assisting with regional control programs. Dr Wells also discovered that Australia already had a range of insects attacking serrated tussock, but these were having Over the years biological control of serrated no effect on the overall problem. In 1993, pressure was again tussock (Nassella trichotoma) has been discussed rising to f’md a biological control and abandoned and rediscussed. solution to the serrated tussock problem. People were writing to Ministers trying to secure Government funding, but to no One of the major problems avail. Shire Councils started raisingforeseen is the use of Frenock for money themselves to fund a search control. It is used solely for control of program in South America, however, not serrated tussock, and therefore has a enough was raised and the issue again relatively small market, and is also a by- quietened down. A search conference product of the CFC process and unlikely was held in Berridale in 1994 which to be available in the not too distant looked at the issue of management rather future. than biological control. AG~dWeed #8 DECEMBER 1996 page 3 FEATURE ARTICLE In 1995 Brace Auld from NSW die back. The fungus is currently being Agriculture secured funding from theidentified and Dr Evans is now culturing International Wool Secretariat to send the strain preparing for host specificity Dr Harry Evans (International Institutetesting. The initial tests will be carried of Biological Control) to Argentina to out on closely related Danthonia and look at pathogens for control of Bathurst Stipa species. If the fungus does not burr. In liaison with CSIRO Division ofinfect these species, funding will be Entomology, Bob Sproule (Ns~W sought to broaden the testing to other Agriculture) and Gratton Wilson grasses and cereal crops with the closest (Cooma-Monaro Shire) raised the fufids relative in the cereal crops being rice. required to extend that survey by One week to look at pathogens on serrated tussock. (Reprinted from Weed Watch, the One unidentified fungus withexternal newsletter of the Cooperative potential was found at 10 of the 17 sites Research Centre for Weed Management surveyed. The fungus attacks the root- Systems, Issue no. 1, June-October stem interface and causes the tussock to 1995) From Abseiling Scouts to a Little White Moth - the Battle with Bit0u Bush Continues itou bush (Chrysanthemoides A 1994 terminating report to monilifera rotundata) is rated as NSW Environmental Trusts produced by B the worst pest plant in the J Toth, P Milham and R Holtkamp Australian coastal environment, (NSW Agriculture) has presented some restricting access to beaches and of the results on bitou bush which have destroying native bushland. It was been attained using chemical control and originally planted during the 1950s to how they can be implemented in an stabilise sand dunes after mineral sand integrated control program. One of the mining which it did so effectively thatinmost exciting results from the aerial the process it managed to displace native spray trials conducted between 1989 and flora, turning vast stretches of coastline 1993 was at least a four fold reduction in into a monoculture. herbicide rates used for bitou bush There are six sub species of control. Trialing of reduced water Chrysanthemoides monilifera in South volumes during aerial spraying has also Africa, but fortunately only two of thembeen completed. A number of trials occur in Australia, C. monilifera were conducted looking at the efficacy monilifera (boneseed) and C. monilifera of chemicals and the effect of adjuvants rotundata (bitou bush). Bitou bush on efficacy and selectivity. currently infests coastal areas of One trial assessed the sensitivity southern Queensland, NSW and Lord of native plant species to herbicides. At Howe Island while boneseed infests the time of the grant proposal a herbicide coastal areas of southern NSW, Victoria, tolerance ranking, had been developed south-eastern South Australia and for seven native species present in Tasmania. substantial numbers at Bherwerre Beach, Jervis Bay. The use of tube plants at page 4 AG~dWeed #8 DECEMBER 1996 FEATURE ARTICLE Jervis Bay and observation of plant 50% and 70% in flower and fruit communities at Hill 60 (Port Kembla) production, respectively. and Hawks Nest extended the tolerance The black boneseed beetle ranking by a further 82 species. The (Chrysolina sp.), the blotched boneseed observations (being conducted by the leaf beetle (Chrysolina picturata), and University of Wollongong) showed thatthe painted boneseed leaf beetle, C.

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