Number 14 February 2000

What’s New In Biological Control of Weeds?

Kiwi Messages at Montana What’s Inside? In the last issue of this newsletter (number 13) we shared some of Kiwi Messages at the gems that the Kiwi contingent gleaned from the 10th Montana 1 International Symposium on Biological Control of Weeds last July. Keeping things in In this issue we reveal the messages that the Kiwis had for the rest perspective 1 of the world. Broom trials and tribulations 3 Taking science to the people 4 The ultimate test 4 A picture says 1000 words 5

Local Hot Gossip 5 Heather beetle 5 Hieracium gall wasp 5 Mist flower fungus 6 Comings and goings 6

Australian Hot Gossip 7 Ragwort plume 7 St John’s wort mite 8 Keeping Things in Perspective Autumn Activities 9 Rowan Emberson, a senior all know some of the earliest lecturer in entomology at projects, like the introduction Tell Me More... 10 Lincoln University who teaches of mustelids to control rabbits, weed biological control, gave a were ill conceived and thought- provoking address biological control has struggled that delivered some useful to regain its credibility ever facts and figures to help dispel since. Today strict regulations the paranoia surrounding the are in place to make sure use of natural enemies to control similar disasters don’t happen weeds. New Zealand has been again, but they may also be Manaaki Whenua Landcare Research undertaking biological control hindering efforts to protect our for more than a century. As we environment. The cost of What's New in Biological Control of Weeds? Number 14 February 2000

“My concern stems really posing a threat to our from the need for endemic flora and fauna? overall caution Let’s see if these critics have a over the valid point. importation of a limitless number Rowan has estimated that we of alien species, have about 20,000 which have the species in New Zealand but potential to acknowledges this figure could displace endemic actually be much higher. “About New Zealand 2,600 of these are not native species...” species, and most have established since European “The addition of colonisation,” says Rowan. untold new alien “Insect biological control agents species can only be for weeds represent only a tiny detrimental to the 1.1% of all our introduced long-term goal of species, and little more than 0.1% preserving our of all the in New Zealand endemic — hardly a significant Rowan Emberson finding out first hand about the successful ragwort programme in Oregon, USA. diversity...” contribution to dilution of endemic insect biodiversity!” developing biological control “There is a danger that the programmes and the cautious supply of new beneficial Rowan also consulted Landcare approach taken by researchers organisms could dry up all Research’s “All New Zealand have always meant that new together if these sentiments are Species Database” (which is agents have tended to come on taken as gospel and not maintained by staff at the stream slowly; recently they challenged,” warns Rowan. So Lincoln Herbarium) to do the have slowed to a trickle. Some are biological control agents same sort of comparison for people seem to believe that restricting the supply of new Number of vascular plant species in New Zealand, April 1999 biological control agents is a Category No. of species good thing. For example, these comments were submitted in Native 449 response to the recent proposal Endemic 1,627 to introduce the hieracium plume Extinct 2 moth (Oxyptilus pilosellae): Total indigenous 2,079 Naturalised 1,796 “It may be better environmental Casual (only small wild populations) 313 management to put up with the Total adventive 2,109 status quo than to deliberately (not indigenous and established in the wild) flood New Zealand with more Total in cultivation only 22,257 alien insects.” 2 What's New in Biological Control of Weeds? Number 14 February 2000

plants. Since early settlers did The Trials and Tribulations a native iconic species such as their darnedest to turn New of Working on Broom in kowhai, the jury is still out about Zealand into a little piece of New Zealand whether or not some damage to Europe in the South Pacific, it is Simon Fowler gave a paper exotic plants might be tolerable, probably not surprising that we explaining the difficulties we given the serious consquences actually have more introduced have encountered during 20 of not controlling rampant plants than indigenous species years of working on broom. weeds. While we have (see table). A significant number While ecological studies suggest identified a number of potential of these are already weeds, in it should be quite feasible to new agents, such as the broom the process of becoming weeds, control broom using a suite of leaf beetle (Gonioctena olivacea), or will be weeds in the future. natural enemies, in practice we gall mite (Aceria genistae), two “Of particular concern are the are still some distance away foliage-feeding caterpillars thousands of species in from achieving this goal. Only (Chesias legatella, Agonopterix cultivation that could jump the two control agents, the broom assimilella), and another seed fence at any time, and the seed beetle (Bruchidius villosus) feeder (Exapion fuscirostre), all number reflects the ease with and broom psyllid (Arytainilla applications have been which people have been able spartiophila), have so far come suspended until we have to import plant material in the to fruition and joined the self- gathered better information past,” says Rowan. introduced broom twig miner about the costs and benefits of (Leucoptera spartifoliella) out in broom to New Zealand and the Rowan’s analysis confirms that the field. consequences of broom agents in many situations biological attacking non-target plants. control is still currently the best, There is no shortage of and least damaging, way of insects attacking broom in protecting our environment. Europe (Pauline Syrett has Insects introduced for biological catalogued 243 species), but control are insignificant in it has been difficult to find diluting biodiversity, and have natural enemies that are the added advantage of being sufficiently restricted in their carefully screened to ensure that host range. For example, the damage to targets other than extremely promising broom their host is minimal. The stem miner (Pirapion immune) greatest threats to our had to be discarded at the The above logo symbolizes the indigenous plant and eleventh hour when it became importance of interactions between communities are the thousands clear that it might pose a pathogens and root-boring insects in of potentially invasive risk to kowhai. Another the biological control of weeds. The introduced plant species and sticking point has been the insects provide an entry point for the the continuous stream of tendency for many of the pathogens and, in combination, provide better control than either accidental insect introductions. agents tested to attack tree agent alone. The background image Unlike biological control lucerne and tree lupin. While on the logo, the jagged line agents, these unwanted insect it is clearly unacceptable for represents the Rocky Mountains, in invaders are often generalist a biological control agent to which Bozeman is situated. species with a wide host range. inflict even minor damage to 3 What's New in Biological Control of Weeds? Number 14 February 2000

Lynley Hayes takes a close look at the yellow wild flowers in Yellowstone National Park, USA, just to check that they aren't weeds.

Taking Science to the People In the earliest days the agents to be released faster, Lynley Hayes gave a paper programme offered control more widely, and more describing our highly agents for a single target, successfully (95% of agents successful technology alligator weed. Since that time released under the programme transfer programme (which a total of 27 agents have been that we know the fate of have amongst other things is offered for 14 target weeds, and established) than ever before. responsible for producing the scope of the programme has this newsletter), and how it been widened to include If you would like a copy of this has evolved during its 20 strategies for managing and paper on the technology years of operation. She enhancing their impacts, more transfer programme, please explained how the success of efficient monitoring and contact Lynley Hayes (see back the programme is due to assessment techniques, the page for contact details). strong relationships built up development of new biological between Landcare Research control programmes, and and participating comprehensive training in The Ultimate Test organisations over this time, biological control methods. As Toni Withers, from Forest and it is probably fair to say a result a network of well- Research at Rotorua, talked there is still no other similar trained people now exists about how we can improve our programme to rival it throughout the country, understanding of the host range anywhere in the world. allowing biological control of biological control agents. She 4 What's New in Biological Control of Weeds? Number 14 February 2000

explained how no-choice tests A Picture Says a Thousand Hawai’i to New Zealand can give either false negative or Words and another on the host false positive results if the The graphic artists at Lincoln range of fusarium blight behaviour of the insect is not were kept busy preparing lots (Fusarium tumidum), which is fully taken into consideration of display posters for the Kiwi being developed as a during test design. Even in contingent to take to the mycoherbicide for gorse and choice tests, insects may respond symposium. Pauline Syrett broom. Hugh Gourlay put differently depending on how prepared a poster outlining together a summary of the hungry they are. A starving our experiences with the old man’s beard programme insect may try to feed on the broom seed beetle and the best and Richard Hill did the first plant it encounters, even if strategies for achieving same for gorse. These posters it isn’t the preferred host. Toni is widespread establishment. are all available for loan working out testing procedures Simon Fowler delved back (contact Lynley Hayes). We that avoid these glitches, and into his former life and are also in the process of is helping a PhD student, summarised the history of adapting the gorse and old Melanie Haines (see Local Hot biological control of weeds man’s beard posters and Gossip page 7), design projects in Mauritius. Jane intend to make them available experiments to show how better Fröhlich was responsible for for loan or purchase along the testing could have predicted two posters: one on the lines of the “What’s Eating?” that broom seed beetles would successful transfer of the mist posters that we produced attack tree lucerne. flower programme from previously.

Local Hot Gossip

Hooray for the heather beetle liberal coating of ash when Mt (Lochmaea suturalis)! In the last Ruapehu erupted soon after issue of “Weed Clippings” we the release, “ said Simon. As reported that, despite intensive the old saying goes: “where searching of the 17 release sites there’s smoke there’s fire”, so in Tongariro National Park, we we are now confident that were unable to find any sign more beetles will be found on that the heather beetle had future visits to the park. survived, apart from a couple of dead bodies. However, another Mass rearing of the hieracium check just before Christmas gall wasp (Aulacidea paid off. Simon Fowler and subterminalis) has gone Paul Peterson found both the extraordinarily well, enabling brownish-coloured adults and us to release this new agent at the greyish larvae at one of the 22 sites just before Christmas. earliest release sites (January the beetles managed to survive The supreme efforts of the 1996). “We are amazed that at this site, which received a Hieracium Control Trust are 5 What's New in Biological Control of Weeds? Number 14 February 2000

beginning to pay off as the site) that they were unable to production while minimising wasps have now been released find any unaffected patches of water wastage. The same in all the worst affected areas mist flower in the Waitakere technology may be made of the South Island from Ranges that they could use for available in future for a range Marlborough through to comparative purposes! of other uses such as warning Alexandra. Southland will be farmers that their milk vats are targeted next with a further 3– There have been a few comings overheating or that someone 4 consignments planned for and goings amongst biological has come onto their property. this month, and next spring it control of weeds staff at Lincoln Perhaps you can develop a will be the North Island’s turn. in recent times. Jeremy Sheat “Bug Wizard” to help us keep completed a 12-year stint with track of some of those elusive The mist flower fungus the group at the end of 1999 to new agents in the field, Jeremy? (Entyloma ageratinae) continues enable him to fulfil his lifelong We wish you all the best for to delight everyone involved in ambition of making a living off your new career and thank you this project. The white smut the land at the family farm in for the legacy you leave behind, was released for the first time a Dunsandel. Jeremy could be particularly the enhanced year ago. Since then it has accused of moving to greener mass-rearing systems that successfully established at all pastures as he also intends to enable us to get new agents out nine release sites and is devote a chunk of his time to in the field as soon as possible. severely defoliating mist promoting a new invention, flower plants (infected plants known as a “Water Wizard”, We would like to welcome are losing 80–100% of their that was the brainchild of his Kylie Galway, who has left her mature leaves). The plants are late father. This piece of home in Australia and shifted fighting back with substantial electronic gadgetry can be used across the Tasman to take up a regrowth, but all in vain as the to alert farmers that their PhD fellowship at Lincoln new leaves are quickly irrigation systems are going University to examine how we becoming infected. The spread awry and therefore maximise can suppress broom more and the impact of the fungus is being carefully scrutinised at one of the release sites in the Waitakere Ranges. Already native plants are beginning to grow in areas that were previously 100% mist flower, and Jane Fröhlich and summer student, Jonathan Boow, have begun to investigate successional changes that occur once mist flower loses its competitive edge. The fungus is spreading so quickly (it has already been found 14 km Jeremy Sheat does his best to avoid making a farewell speech by hiding behind his away from the nearest release topiary rooster (one of a matched pair given to him as a farewell present from the team). 6 What's New in Biological Control of Weeds? Number 14 February 2000

effectively by integrating the control techniques that are available to us. Landcare Research and the Co-operative Centre for Weed Management Systems in Australia have joined forces to provide funding for this study, which will provide new ammunition to allow us to tackle this weed problem more effectively. Kylie brings with her husband Peter, who has until recently been working on biological control of The three broom PhDs: Kylie Galway, Helen Harman, and Melanie Haines (left insect pests and weeds, to right). including lantana (Lantana camara), and her labrador Molly. to worry about snakes and techniques to DNA fingerprint Kylie has previous experience in other nasties! the broom twig miner biological control, having (Leucoptera spartifoliella) and worked until recently with two Broom PhD’s seem to be the determine its origins, and has Australian plants, the paper order of the day at present as now rejoined the group full- bark tree (Melaleuca there are two others in progress time. Helen’s new skills quinquenervia) and the old world at Lincoln. Melanie Haines should enable us to develop climbing fern (Lygodium began a study in 1999 on the even more successful projects microphyllum), which have non-target impacts of the in future by, amongst other become invasive in the Florida broom seed beetle (Bruchidius things, allowing us to identify Everglades, USA. We are sure villosus) and in particular its the best strains of agents to that Kylie is looking forward to impact on tree lucerne. Helen use. We will keep you posted clambering through in broom in Harman is coming to the end on the findings of all three New Zealand without having of her study using molecular PhD’s in future issues.

Australian Hot Gossip

A natural enemy of ragwort hind wings divided into three that originates from Spain has feathery plumes. The larvae recently been approved for initially burrow into the leaf release in Australia. The petioles and then tunnel ragwort plume moth down into the crown and (Platyptilia isodactyla) is roots where they continue to similar in appearance to our feed and grow. The damage hieracium plume moth caused by older larvae is (Oxyptilus pilosellae) with its usually fatal to ragwort plants Ragwort plume moth 7 What's New in Biological Control of Weeds? Number 14 February 2000

Ragwort Agent Status

Crown-boring moth Established in Tasmania and Victoria. Cochylis atricapitana Reducing the height and growth of flowering plants and is killing smaller rosettes at at least one site.

Ragwort flea beetle Well established and reducing ragwort in Tasmania. Longitarsus flavicornis Established only in high altitude and high rainfall areas in Victoria with no significant impact yet.

Ragwort flea beetle Established at a few sites in Tasmania and Victoria with no Longitarsus jacobaeae significant impact yet.

Cinnabar moth Establishment doubtful. Tyria jacobaeae

and it is hoped this new more than 300 sites and is significant impact because, agent will strengthen the now established throughout when they were removed from existing ragwort attack most of the weed’s range in equivalent plots, the plant (summarised in table). New South Wales, Victoria, density increased by 58%. At and South Australia. As the the other site the results were A combination of the impacts old saying goes “size doesn’t even more dramatic. The of the greater St John’s wort matter” and our Australian density of plants in plots beetle (Chrysolina colleagues are delighted with where the mites were present quadrigemina), improved the impact of one of the decreased by 29%, whereas pasture management, and the world’s smallest plots free of mites increased by use of herbicides has largely biological control agents. A 65%. Mite-infested plants dealt with the problem of St reduction in the height and were also more stunted, John’s wort in open flat density of St John’s wort deformed, and generally less grasslands in Australia. infestations was noticeable at vigorous. However, the weed has release sites after only a few remained a problem in areas years and recently an where pasture improvement assessment study has been These snippets were taken is not feasible, so another undertaken at two sites in from issue 11 of Under Control agent, the St John’s wort mite Victoria to quantify this. At - Pest Plant and Animal (Aculus hyperici), has been one site the density of St Management News published enlisted to add pressure to John’s wort increased by 12% by the Keith Turnbull the plant. Since 1991 this tiny despite mite activity; however, Research Institute, Victoria, mite has been released at the mites were still having a Australia, ISSN 1328–2425. 8 What's New in Biological Control of Weeds? Number 14 February 2000

Autumn Activities

Autumn is a good time for harvesting and redistributing ragwort flea beetles, nodding thistle crown weevils (Trichosirocalus horridus), nodding thistle gall flies (Urophora solstitialis), gorse pod (Cydia succedana), old man’s beard leaf miners (Phytomyza vitalbae), and old man’s beard fungus (Phoma clematidina).

For the first four agents listed refer to the appropriate pages in “The Biological Control of Weeds Book” for detailed instructions on how to go about this. distribution. Simply collect as spores off by swilling them Avoid sealing up ragwort flea much mined leaf material as around in a bucket of water. beetles with large quantities you can from a heavily infested Transfer the resulting liquid of ragwort in non-breathable site and leave this on the ground into a sprayer (it is better to containers in hot weather. at the new site where it won’t keep one especially for this Also be careful to sort through get blown away. You may purpose to avoid any material that you collect notice small brown pupal cases contamination with herbicides with your garden-leaf vacuum stuck to the undersides of leaves. etc.) and apply it to some old so that you don’t shift any New adults will quickly man’s beard foliage. It is pests, like the clover root emerge from these and colonise preferable to soak one area weevil (Sitona lepidus), at the new sites. Any larvae still thoroughly than to apply the the same time. mining the leaves will complete mixture too thinly. Because the development on the cut material, fungus needs moisture to be Old man’s beard leaf miners and provide additional new effective, where possible are dispersing extremely adults for establishment. choose shady damp sites. quickly throughout the country, If it rains heavily soon but if you do come across any Likewise it is easy to shift old after application, then the uninfested patches before they man’s beard fungus to new spores may get washed off do, then you can easily help to sites. Collect blackened, and you may need to repeat fill any gaps in their infected leaves and wash the the procedure. 9 What's New in Biological Control of Weeds? Number 14 February 2000

Tell Me More ...

Question: Should I release several get going. To maximise their pods to sustain the seed control agents for the same weed chances of survival, you want feeder. There is also the at the same site? to give new agents the best danger of putting all your possible start and that means eggs in one basket and Although it may be more giving them the healthiest having them all wiped out in convenient to do so, as a food supply available. Be a freak event such as a fire or general rule we would careful even if you are a flood. However, it may still suggest that in the early dealing with agents that be feasible to release new stages of a biological control don’t attack the same part of agents, especially those that programme you don’t put out the plant, for example, disperse slowly, within just a several control agents for the combining a foliage feeder few hundred metres of each same weed at the same site. and a seed feeder. While the other. You can start to load Obviously the ultimate aim is seed feeder is unlikely to up sites with the full to have all the agents out harm the foliage feeder, the complement of agents once there working together as one converse is not necessarily they are well established and big happy family, but new true. If the foliage feeder does easy to harvest in good agents are usually rare and its stuff, then the plants may numbers. If in doubt about precious and sometimes need produce few, if any flowers, what to do don’t be afraid to be mollycoddled until they and there may not be enough to ask us!

Stop Press!! This newsletter is now available online! Check out our website!

This newsletter is produced three times a year by: Editor: Lynley Hayes Manaaki Whenua – Landcare Research NZ Ltd Email: [email protected] PO Box 69 Layout: Kirsty Cullen Lincoln Cartoons: Anne Rose New Zealand Ph +64 3 3256 700 ISSN 1173-762X Fax +64 3 3252 418 Website: www.landcare.cri.nz

Manaaki Whenua. Manaaki Tangata: Care for the land. Care for the people.

This information may be copied and distributed to others without limitations, provided Landcare Research and the source of the information is acknowledged. Under no circumstances may a charge be made for this information without the expressed permission of Landcare Research.

10