Opuntia Robusta J.C.Wendl

weed. They tried many different control methods and techniques including Fifty years of “wheely prickly cactus” (Opuntia mechanical removal, spraying, burning, ‘shotgun’ delivery and injection, and robusta) in the Maldon Shire various combinations of these methods. They found that surface spraying was not Lee Mead effective because of the thick waxy skin of the cactus lobes, and their high moisture President Tarrangower Cactus Control Group Inc. content prevented burning. The rugged PO Box 1, Maldon, Victoria 3463, Australia. terrain as well as both the very sticky substance of the plants and their ability Abstract stated that these inspectors ‘had been to regenerate from fragments rendered An article in the Maldon Times dated May instructed that strict enforcement of the removal by machinery just as ineffective. 1963, tells us that the Vermin and Noxious Act was necessary. Landholders who fail After much trial and failure, these Weeds Destruction Board instructed to comply with the provisions of the Act pioneer ‘cactus warriors’ developed an Maldon Shire inspectors to immediately will be liable to prosecution’. efficient injection tool consisting of a very carry out control measures against wheel This article confirms that wheel cactus long needle attached to a small backpack cactus (Opuntia robusta J.C.Wendl. ex was a problem in the Maldon area in the tank filled with herbicide (Figure 1). They Pfeiff.). 1960s, and that governments were signif- concluded that injection of herbicide Thirty years later in the 1990’s, local icantly involved in solving this problem at into the lobes of the plant was the most farmers were alarmed to find wheel cactus that time, treating the weed and enforcing still spreading on their properties. These the associated legislation. concerns lead to optimistic collaborations Anecdotal evidence from local farmers between neighbouring landholders, local indicates that there was no significant Landcare groups and Parks Victoria. In the wheel cactus problem in the district early 2000’s these community members during the 1970s and 1980s, suggesting formed a new group, the Tarrangower that the combination of government Cactus Control Committee, specifically financial support and, possibly, more to tackle the increasing problem of wheel compliant and committed landholders cactus around Maldon in central Victoria. in that era, led to the desired effect of This group gained initial funding from keeping wheel cactus under control for a the Victorian State Government which least a couple of decades. Farmers in the Figure 1. Ian Grenda injecting wheel helped to establish years of knowledge district also believe that the rabbit plague cactus using the current injection kit. building, education and information during the 1970s and 1980s contributed sharing with local communities. Despite to keeping wheel cactus under control the past 20 years of focused, determined because they ate the very small plants. and untiring work by many volunteers, But how did it get here? Our heaviest there are now more infestations, larger infestations have always been found at seed banks and a greater spread of wheel Pigeon Hill and the Three Sisters, rocky cactus in our district. outcrops both within five kilometres of Fifty years on, it is heartbreaking to see Cairn Curran Reservoir, near Maldon in wheel cactus still growing in our beautiful central Victoria. Some plants within these parklands, and devastating to see land infestations are so large we believe they owners overwhelmed with the infesta- must have been there for many decades. tions on their properties. Without more Was this plant introduced by immigrant rigorous control measures wheel cactus workers employed for the construction of may soon become a major environmental Cairn Curran Reservoir, who lived nearby? and economic disaster in our region. Was it introduced as an ornamental Figure 2. Landholders attending a This paper presents an overview of garden plant or as a supply of fruit, similar wheel cactus information day in 2006. the eradication methods and the work to the common prickly pear (Opuntia performed by our group of ‘cactus stricta (Haw.) Haw.)? This close cousin warriors’ over the past 20 years, and is frequently found within the Maldon outlines the actions that we believe need district but in isolated locations, often at to be taken in the future ‘war’ against the sites of former homesteads, and has wheel cactus. never spread or become a problem weed like wheel cactus. The past The late 20th century During the 1990s, Wheel cactus in the Maldon Shire local farmers became anxious about the The mid 20th century An article in renewed spread of wheel cactus on their the Maldon Times, dated 13 May 1963, properties, and local Landcare groups reported that the then Vermin and likewise, became alarmed at the prolif- Noxious Weeds Destruction Board had eration of wheel cactus in our unique, historic goldfields landscape. Several ‘directed all inspectors controlling areas Figure 3. Ian Grenda indicating the within the Maldon Shire to carry out concerned neighbours in the Nuggetty effect of different chemicals at our remedial measures immediately against area just north of Maldon joined forces the spread of wheel cactus’. It also to determine the best way to destroy the 2015 workshop. 2 Plant Protection Quarterly Vol.31(1) 2016 efficient method, although extremely events have developed into regular cactuswarriors.org). Increasing knowl- labour intensive and expensive. These monthly community field days involving edge has been a priority since we real- trials highlighted how difficult wheel many volunteers, and the committee has ised years ago that community members cactus is to eradicate and is hence, a since become the Tarrangower Cactus commonly believed wheel cactus was serious threat to land, livelihoods and the Control Group Inc. ‘just prickly pear’ and of no significant environment. concern. We also regularly release media reports, notices and information using Grassroots community action In 2005, The Present conventional media, including print, tele- members of three local Landcare groups, Achievements of the Tarrangower vision and radio. Maldon, Nuggetty and Baringhup, formed Cactus Control Group To increase our group’s profile, we a new committee to specifically tackle participate in annual local events, such as Since the increasing problem of wheel cactus, Increased community awareness holding information stalls at the agricul- the formation of our group in 2005, we and named themselves the Tarrangower tural show and Maldon Market, and have Cactus Control Committee. Three repre- have significantly increased local commu- fun dressing up for the street parade in sentatives from this new group promptly nity awareness and knowledge about the the Maldon Easter fair. applied for funding from the Victorian threat and eradication of wheel cactus. In May 2015 we held a half day work- Government and succeeded in gaining Attendances at monthly community field shop and field trip, inviting participants a grant of $30 000 to work in conjunc- days has grown from less than 10 when from all surrounding shires and relevant tion with Parks Victoria to control wheel they began in 2005 to more than 50 in government authorities (Figure 3). The cactus on private and park lands. This the past few years. Increases in awareness main objectives of this workshop were to funding helped establish a series of field has been achieved partly by means of demonstrate different control methods demonstrations to educate land holders various brochures we have produced and, as well as to prevent infestation spread by on best control methods (Figure 2). These since 2013, a dedicated website (www. advising stakeholders from surrounding districts how to treat isolated infestations. Increased land owner participation The Tarrangower Cactus Control Group has been working relentlessly over the past ten years informing, teaching and assisting the landowners of Maldon, Baringhup and Nuggetty. Beginning with an ‘Open day’ in collaboration with Parks Victoria in October 2005, we have held monthly community field days at both private and public locations where we demonstrated best control methods (Figure 4). At other times when requested, our volunteers also hold voluntary demonstrations and advise property owners who cannot attend field days. Our focus on education has also been greatly aided by compiling and distributing a number of different brochures explaining the threat Figure 4. ‘Cactus warrior’ volunteers injecting wheel cactus at a community field of this weed and giving detailed advice day. on eradication. In addition, we provide free loans of injection and digging equipment, some- times even free herbicide, as incentives to land owners, as well as physical assistance to give the landowner a helping hand and moral support. We purposely endeavour to give advice in a friendly manner and with an optimistic outlook, to maintain positive relationships with the property owners. Using these various strategies, we have successfully increased the number of local property owners who now have the equipment and knowledge to control wheel cactus, and who currently control its growth on their land. Improved techniques During the past ten years, the Tarrangower Cactus Control Group has continued to investigate improvements to techniques and ways Figure 5. Pasture near Cairn Curran Reservoir in central Victoria now infested to reduce wheel cactus management with wheel cactus. costs. We have completed several pilot Plant Protection Quarterly Vol.31(1) 2016 3 trials comparing different equipment, methods and herbicides and currently use a combination of different strategies. For example, we inject herbicide into large plants but also use physical removal and burial of smaller plants to reduce the use and cost of chemicals. Successful control in historic parks In a very successful partnership with Parks Victoria we continue to control wheel cactus proliferation in our historic goldfields parks and have prevented any new heavy infestations in these public areas. This success has been mostly due to the excellent collaboration and coordinated efforts between the community and Parks Victoria staff.

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