First Hand Experiences in Managing Different ... - Weeds Australia

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! Asparagus declinatus^! Asparagus asparagoidesCase study siteNo Reported Occurrencerequires detailed understanding of plant life cycles,soil types and climatic conditions.In the Adelaide Hills and Fleurieu Peninsularegions, many native annuals such as orchids, liliesand ferns withdraw into their rootstock for a periodof summer dormancy with the onset of hotter, drierconditions in mid to late spring. The asparagusweeds, with their larger tuber and rhizome systems,persist a few weeks longer on the surface. Duringthis time they can be sprayed without impacting thedormant native plants.Spraying with a strong solution at this stage oftheir cycle has proven particularly effective, asthe herbicide is drawn down into the rootstock.However, younger seedlings fade earlier in theseason and are likely to be missed. It is importantto revisit the site during the same window ofopportunity the following year to manage seedlings.‘If the project runs for three to four years, you’vegot a good chance of picking up all the weeds.’Refining the techniqueKnapsack foliar spraying using metsulfuron-methylat 5–7 g per 100 L is the preferred application.A surfactant is added, which makes the herbicidego further and helps penetrate the waxy asparagusfoliage. Fine spray nozzles are used on the veryfine foliage of A. declinatus which enables theoperator to apply small hits onto little patches andavoid overspray. Dye is used to keep careful trackof applications.‘Metsulfuron-methyl is very effective on A.declinatus and A. asparagoides. Glyphosate willwork but it is less selective and can do a lot of offtargetdamage.’Instead, glyphosate is used to treat watsonia(Watsonia meriana var. bulbillifera) and Africancornflag (Chasmanthe floribunda (Salisb.) N.E.Br.)using similar principles to those for asparagusweeds.Reading the sites – timing is keyThere is a lot of variation from site to site, soeach must be assessed individually and itsconditions understood. During the brief window ofopportunity, usually in October to early November,the work is intensive. As rainfall and temperaturevary from year to year, so does the timing. Thismakes it difficult to forward plan and covermultiple, dispersed sites. For example, plants willdry off earlier at sites with a northerly aspect or onexposed heights and will linger longer at sites witha southerly aspect or in sheltered valleys where it iscooler and wetter.Soil type and weather conditions affect how longmetsulfuron-methyl has a residual activity in thesoil. When to control must be carefully plannedaround predicted weather conditions to limitdamage to off-target plants. Typically, there is atwo-week dry spell after spring rain events, givingsufficient time for the herbicide to become inert.98
Asparagus asparagoides before treatment in grey box grassywoodland, Belair National Park, Mount Lofty Ranges, SAAdditional time is needed in acid soils as thechemical is more persistent. Soils rich in organicmatter tie up the chemical and prevent it fromaffecting other plants.There is a high level of knowledge and expertiserequired to use metsulfuron-methyl effectivelyin bushland settings. Excessively high rates,heavy applications, wet conditions and limitedunderstanding of soil types and native ecology canlead to devastating off-target damage.Making bushcare everyone’s businessSAIF director, Kieran Brewer, sees bushcare projectsas an opportunity to share knowledge about nativeplants, ecology and weed management.‘You work with people who really know theirplants. Volunteers have got a strong connectionwith their conservation site, their heart’s in it,they’ve got intimate knowledge and they’re greatto work with.’A project running in the Mt Lofty Rangesdemonstrates that working closely with acommunity group can disseminate skills, buildlong-term capacity and manage fragile species.The Woodcutters Road Environmental ProtectionAssociation, formed to conserve natural heritagevalues across their adjoining properties, whichcontain some high-value bushland, managesthe project. A spectrum of weeds is presentincluding A. asparagoides. Weed control bycontractors is into its fourth year. Populations ofGrey box grassy woodland, Belair National Park, Mount Lofty Ranges,South Australianationally endangered pink-lipped spider-orchids(Caladenia behrii Schltdl.) and stiff white spiderorchids(Caladenia rigida R.S.Rogers) are carefullymanaged. An integral contribution is being madeby a community member who was mentored by aNRM Officer, received training and now monitorsthe progress of every single plant, recordingpopulation, flower count and seed set.Achieving successMaintaining focus on the core outcomes ofpreserving rare species and building the resilienceof native vegetation has been the key to successwith SAIF’s projects. Weed management isalways conducted within this context and controltechniques are carefully selected and timed to limitdamage to existing native vegetation.Over the course of weed management, sites arecarefully monitored and documented, usingmultiple photopoints, mapping, written reportseach season and site visits with clients to discussprogress. After sufficient time has passed to showweed control objectives have been met, a finalinspection with the client usually concludesthe sign-off process. Long-term monitoring andmaintenance is then continued by the client, oftenby a dedicated community group.‘Instead of weeds you see all the native plant coveryou’d ever want.’99
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First Hand Experiences in Managing Different ... - Weeds Australia

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