{"id":11738,"date":"2019-08-31T01:28:06","date_gmt":"2019-08-31T01:28:06","guid":{"rendered":"https:\/\/www.environment-hawaii.org\/?p=11738"},"modified":"2019-08-31T02:54:36","modified_gmt":"2019-08-31T02:54:36","slug":"advances-in-biocontrol-are-praised-at-hilo-meeting-on-invasive-species","status":"publish","type":"post","link":"https:\/\/environment-hawaii.org\/?p=11738","title":{"rendered":"Advances in Biocontrol Are Praised At Hilo Meeting on Invasive Species"},"content":{"rendered":"\n
\"\"
Koa bug. USFWS<\/figcaption><\/figure>\n\n\n\n

One of the oldest arguments against biological control concerns the introduction of the mongoose to Hawai\u2018i. <\/p>\n\n\n\n

True: mongooses were introduced to\nHawai\u2018i in the 1880s by sugar growers\nwho believed they would knock back the\nproblem of rats in cane fields. But since\nthe mongoose is active during the day,\nwhile the rat is nocturnal, the two rarely\ncrossed paths.\n<\/p>\n\n\n\n

The mongoose is now well established on\nmost islands in Hawai\u2018i, where it has done\nmuch more damage to beneficial animals,\nincluding native birds, than to the islands\u2019\nstill robust rat population.\n<\/p>\n\n\n\n

But the misguided effort hardly qualifies as an example of biocontrol gone wrong. As the Hawai\u2018i Invasive Species Council points out on its website, \u201cthe introduction of this species by private individuals in the sugarcane industry was not part of any scientific biological control process. <\/p>\n\n\n\n

\u201cBiological control, or biocontrol, is a robust scientific field in which research is done to identify a predator or pest of a given invasive species from its home range, followed by extensive research to determine\nwhether the predator or pest, if introduced\nto Hawai\u2018i as a biocontrol agent, would\nimpact only <\/em>the invasive species in question.\nMongoose did not undergo this evaluation\nprior to entry and should not be considered\nan example of biocontrol.\u201d\n<\/p>\n\n\n\n

At a two-day conference last month on invasive pests in Hawai\u2018i, sponsored by the Cooperative Extension Service of the University of Hawai\u2018i\u2019s College of Tropical Agriculture and Human Resources (CTAHR), just how rigorous today\u2019s biocontrol efforts have become nearly a century and a half after the mongoose experiment began was apparent in numerous presentations. <\/p>\n\n\n\n

And also, just how successful. <\/p>\n\n\n\n

Addressing Fears Of Non-Target Attacks <\/h4>\n\n\n\n

Mark G. Wright is a professor at CTAHR\u2019s Department of Plant and Environmental Protection Sciences. His presentation, coming at the close of the conference, looked at the long history of biocontrol, going back 125 years in Hawai\u2018i. <\/p>\n\n\n\n

While acknowledging \u201cunfortunate errors\u201d in the selection of some biocontrol agents as well as some well publicized instances of the biocontrol agents hopping onto non-target species, \u201czero non-target attacks have been recorded in the field since 1975,\u201d Wright told the 75 or so academics, land managers, and other interested parties in attendance. <\/p>\n\n\n\n

In any event, \u201cjust because something attacks a non-target doesn\u2019t mean there\u2019s an impact,\u201d Wright said. One of the best- known recent examples of this occurred when the endemic, jewel-like koa bug and its eggs were attacked by two parasitoid wasps that had been introduced in the 1960s as biocontrol agents to suppress the southern green stink bug, an agricultural pest. <\/p>\n\n\n\n

Citing a study by Tracy Johnson, an entomologist now working for the U.S. Forest Service in Volcano, and colleagues, Wright said that predation on koa bug eggs by one of the wasps (Trissolcus basalis <\/em>Wollaston) amounted to at most 26 percent of all eggs preyed upon. That was overshadowed by far by predation by other animals (ants and spiders), which accounted for 87 percent of predation. <\/p>\n\n\n\n

Predation on adult koa bugs by the other wasp, Trichopoda pilipes<\/em>, was near zero at 21 of the 24 sites Johnson and his colleagues surveyed, although at three sites, with a higher density of koa bugs, predation was as high as 70 percent among adult female bugs, 100 percent among males, and 50 percent among fifth instars. \u201cEffects of intentionally introduced parasitoids were relatively minor,\u201d Johnson and his colleagues found. <\/p>\n\n\n\n

In any case, Johnson and his colleagues wrote, \u201cStudies of purposely introduced biological control agents should not over- shadow studies of other natural enemies; the invasion of koa bug habitats by alien keystone predators such as ants poses perhaps the greatest risk to the long-term stability of koa bug populations. Continuing habitat degradation could compound the negative effects of enemy attack.\u201d <\/p>\n\n\n\n

Still, Johnson told Environment Hawai\u2018i, <\/em>\u201cI would not characterize the impacts of the parasitoids on koa bugs as negligible. … [There are] a number of reasons why Trichopoda\u2019s <\/em>impacts are concerning, even though on average they measured low.\u201d <\/p>\n\n\n\n

Wright noted that today\u2019s strict reviews of prospective biocontrol agents, much tougher than they were half a century ago, and the successes of several introductions \u2013 notably the parasitoid wasps that attacked the wiliwili gall wasp \u2013 have swayed even some of the more outspoken opponents of biocontrol.
<\/p>\n\n\n\n

\u201cClassical biocontrol can contribute to\nconservation efforts,\u201d he concluded, adding\nthat it now enjoyed \u201csubstantial support\nfrom previous biocontrol opponents.\u201d\n<\/p>\n\n\n\n

Moving Toward Biosecurity\n<\/h4>\n\n\n\n

While biocontrol can be effective,\nit\u2019s the costly pound of cure when\ncompared with the ounce of prevention that\nquarantine and other biosecurity measures\ncan provide.\n<\/p>\n\n\n\n

In 2017, the Hawai\u2018i Invasive Species Council, made up of designees of five cabinet-level department heads (Agriculture; Health; Land and Natural Resources; Business, Economic Development, and Tourism; and Transportation) and the University of Hawai\u2018i, adopted a 10-year biosecurity plan that calls for 147 specific actions to be taken over the next decade. Seventy-five of those (51 percent) deal with preventing potential pest species from being shipped here (pre-border) or intercepting them on arrival (border). And most of those tasks fall under the jurisdiction of the state Department of Agriculture (DOA). <\/p>\n\n\n\n

Randy Bartlett, interagency coordinator for HISC, outlined progress made toward the plans goals. As of last January, he said, 50 percent of them had been initiated, completed, or were ongoing in perpetuity. <\/p>\n\n\n\n

Completed actions include restoration of the vector control program in the Department of Health; a relaunch of the Department of Agriculture\u2019s detector-dog program; and development of technology needed for the first phase of an electronic manifest program for incoming cargo shipments. Work still in progress involves beefing up the restricted-plant list of the DOA; developing emergency response plans for rapid \u2018ohi\u2018a death; addressing vessel biofouling; and finding biocontrols for miconia, Himalayan ginger, and albizia. <\/p>\n\n\n\n

Altogether, Bartlett said, the state spends about $57 million a year \u2013 four tenths of a percent of its operational budget \u2013 on current biosecurity measures. If full implementation of the biosecurity plan were to occur, it would take $38.7 million a year more, and still just amount to seven-tenths of a percent of the total operational budget. <\/p>\n\n\n\n

At the close of his presentation, Bartlett\nwas asked whether all the money in the\nstate\u2019s \u201ccargo inspection fund\u201d was being\nused for inspection.\n<\/p>\n\n\n\n

\u201cI don\u2019t think so,\u201d Bartlett replied.\n<\/p>\n\n\n\n

That fund \u2013 technically, the Pest Inspection, Quarantine, and Eradication (PIQE) Fund \u2013 is the recipient of a fee of 75 cents for every thousand pounds of freight brought into the state. <\/p>\n\n\n\n

Under Hawai\u2018i Revised Statutes section 145A-4.5(b), which establishes the fund, moneys are to be used by the DOA for \u201cthe operation of biosecurity and pest inspection, quarantine, eradication, and monitoring programs,\u201d among other things. <\/p>\n\n\n\n

The state auditor reported last October that as of the close of fiscal year 2018, the fund balance stood at around $8.3 million. According to a DOA report to the Legislature last December, the department collected about $6.1 million in fees and spent around half that on personnel costs in the Plant Quarantine branch. About $3 million was spent on \u201cother current expenses.\u201d <\/p>\n\n\n\n

Those other expenses did not, apparently,\ninclude travel to Hilo. No one from Plant\nQuarantine or any other division of the\ndepartment attended the conference.\n<\/p>\n\n\n\n

Status Updates\n<\/h3>\n\n\n\n

Many presentations at the conference\nprovided updates on the status of\ninvasive species already present in the\nislands.\n<\/p>\n\n\n\n

Just two vertebrate species were addressed\n\u2013 the rose-ringed parakeets of Kaua\u2018i and the\nmitred conures on Maui. No four-legged\nanimals \u2013 mouflon, deer, or feral pigs, goats,\nsheep, cattle, and cats \u2013 merited mention.\n<\/p>\n\n\n\n

Conjures and Parakeets<\/em><\/h4>\n\n\n\n

As for the mitred conures, Adam Radford\nof the Maui Invasive Species Committee\n(MISC) said, \u201cWe\u2019re close to getting rid\nof them on Maui. There used to be about\n200 birds, but now we\u2019re down to about 15\nindividuals.\u201d\n<\/p>\n\n\n\n

The fact that all of Hawai\u2018i\u2019s invasive species committees are on a firearms stand-down, Radford said, meant that it was not possible for his team to use firearms to kill off the remaining birds. Efforts to capture the cliff-dwelling birds using mist nets, lures, audio playbacks, and feeding stations, or by rapelling down cliffs \u2013 have been unsuccessful, he said. <\/p>\n\n\n\n

In the meantime, some of MISC\u2019s partners, including the Department of Land and Natural Resources and The Nature Conservancy, were helping to track down the last few conures. (The ISCs and other agencies affiliated with the Research Corporation of the University of Hawai\u2018i have not been allowed to use firearms since late 2016, pending a review by the deputy at- torney general assigned to RCUH.) <\/p>\n\n\n\n

The rose-ringed parakeets on Kaua\u2018i pose a different set of challenges. The bird is found in Hawai\u2018i on the islands of Kaua\u2018i and Oahu, with a nascent population on the Big Island, said Sean Siers of the U.S Department of Agriculture\u2019s Animal and Plant Health Inspection Service, reporting on the work of Page Klug, who works out of APHIS\u2019s North Dakota wildlife research center. <\/p>\n\n\n\n

On both Kaua\u2018i and O\u2018ahu, the birds have\nbecome a major pest of agricultural crops,\nbut on Kaua\u2018i, they have become a threat to\npublic health as well, with thousands of the\nparakeets congregating in urban areas.\n<\/p>\n\n\n\n

\u201cThe bread-and-butter\u201d tool to control the birds will be firearms, Siers said. \u201cShooting is the only way successful eradication has occurred,\u201d he said, citing the experience of an island in the Seychelles. <\/p>\n\n\n\n

\u201cWe\u2019re looking at protocols for a shooting\ncampaign\u201d on Kaua\u2018i, Siers said. Perhaps\nairguns could be used in populated areas,\nand shotguns employed elsewhere, but \u201cyou\ncan\u2019t blast every parakeet out of every tree.\nMost habitat is in urban areas. There\u2019s also\nthe fear that if you just start blasting them\nin urban areas, they\u2019ll move mauka.\u201d\n<\/p>\n\n\n\n

Other options could include toxicants, although no registered toxicants are available, Siers added. Falconry or other predators might also be used to control the population \u2013 although, Siers noted, this is an \u201cunlikely\u201d option.
<\/p>\n\n\n\n

Jane Anderson of Texas A&M University has been engaged to do further work on\nways of controlling the rose-ringed parakeet,\nSiers said.\n<\/p>\n\n\n\n

Little Fire Ant<\/em><\/h4>\n\n\n\n

\u201cThrow a penny anywhere in Hilo and you\u2019ll hit six little fire ants.\u201d <\/p>\n\n\n\n

That statement, from Cas Vanderwoude \u2013 who probably knows more about the species Wasmannia auropunctata <\/em>than any other living soul \u2013 may have been exaggerating, but not by much, as any Hilo resident can attest. <\/p>\n\n\n\n

Vanderwoude, director of the Hawai\u2018i Ant Lab, described the ant as a \u201cthree-dimensional invader.\u201d No commercial control products address it, and practically no research has been done on ants in trees, where the LFA can live. And it\u2019s those \u201ccanopy ants,\u201d he said, that are responsible for most of the sting incidents: \u201cArboreal ants that fall out of trees do most of the damage.\u201d <\/p>\n\n\n\n

The LFA is resilient. \u201cThey have an extraordinary ability to recover from our best efforts to kill them,\u201d Vanderwoude said. \u201cWhatever I do has a maximum impact on ants for about eight weeks.\u201d <\/p>\n\n\n\n

The species \u201cdefies efforts to control it by conventional means for three main reasons,\u201d Vanderwoude wrote in his abstract of the presentation. These are: \u201can abundance of queens (more than 50 pre square meter), a remarkable ability to recover from a catastrophic event in a short time frame, and a tree-dwelling component out of reach of conventional application equipment.\u201d <\/p>\n\n\n\n

\u201cHawai\u2018i is basically screwed,\u201d he said.\n<\/p>\n\n\n\n

\u201cAll of Hawai\u2018i below 3,000 feet elevation\nis ideal habitat\u201d and the ant has not begun\nto fill out its possible range.\n<\/p>\n\n\n\n

A survey of literature about the ant that\nVanderwoude undertook showed that as\nrecently as twenty years ago, the LFA was\npractically an unknown species: \u201cOnly one\npaper, in 1997, talked about the little fire\nant as potentially invasive.\u201d\n<\/p>\n\n\n\n

Vanderwoude found just 341 papers on\nthe little fire ant, fewer than 40 of which\nwere relevant \u2013 and just 11 of those talked\nabout control or impacts.\n<\/p>\n\n\n\n

By comparison, there were 2,975 papers\non Solenopsis invicta, <\/em>the red imported fire\nant.\n<\/p>\n\n\n\n

The little fire ant was first detected on the\nBig Island in 1999. Since then, it\u2019s spread\nall over the island and now has been found\non Maui, O\u2018ahu, and Kaua\u2018i, where efforts\nto limit the spread of the ant continue to\nbe made.\n<\/p>\n\n\n\n

Key hub ports in the Pacific \u2013 in Hawai\u2018i, Guam, Tahiti, and Fiji \u2013 are now all infested, Vanderwoude said, \u201cand this will most likely lead to the continued spread of this species.\u201d <\/p>\n\n\n\n

Vanderwoude\u2019s lab has developed baits\nthat can be applied aerially and other means\nof addressing the problems associated with\nLFA infestation. The lab\u2019s outreach arm\nworks with large landowners, farmers, and\nothers to help in developing management\nstrategies.\n<\/p>\n\n\n\n

Rat Lungworm<\/em><\/h4>\n\n\n\n

Little fire ants are, as the name suggests,\npretty small \u2013 about a millimeter and a half\nin length. Line up a hundred of them, end\nto end (pretty easy to do in Hilo), and the\nline will be around six inches long.\n<\/p>\n\n\n\n

By contrast, the rat lungworm, An-\ngiostrongylus cantonensis, <\/em>is microscopic. Yet\nonce in humans, it can cause devastating\nhealth effects, even death.\n<\/p>\n\n\n\n

As Sue Jarvi of the Daniel K. Inouye\nCollege of Pharmacy at the University of\nHawai\u2018i-Hilo explained, humans are an\naccidental host, along with dogs, horses,\nand other animals. The rat lungworm\u2019s life\ncycle ideally involves snails or slugs, which\nare intermediate hosts, to rats.\n<\/p>\n\n\n\n

Rat lungworm has been known to be in Hawai\u2018i for decades, but human infections were relatively rare until recently. Many have linked its spread to the arrival of the Asian semi-slug, which carries many times more rat lungworm larvae in its tissue than other snails and slugs. The semi-slug was not found on Hawai\u2018i island until 2004, but it has spread widely since then, particularly in the Puna district.
<\/p>\n\n\n\n

In East Hawai\u2018i island, 94 percent of rats tested were found to be infected with\nrat lungworm, while 70 percent of the\nsemi-slugs were infected. Even a tiny piece\nof an infected snail can contain hundreds\nof larvae.\n<\/p>\n\n\n\n

Larvae can live outside of snails or slugs\nand can be transmitted to humans in a\nvariety of ways. Eating unwashed produce\nor snails can lead to infection, but also\ndrinking water from catchment systems\nwhere larvae-carrying mollusks have fallen\nin. According to Jarvi\u2019s research, live and\ninfective larvae emerge from drowned slugs\nor snails within three or four days, and they\ncan survive on their own in the water for at\nleast three weeks.\n<\/p>\n\n\n\n

Since most of the larvae sink, answering\nthe question of what filters are effective in\ntrapping the larvae is important for Puna\nresidents on catchment. Just one of the\nfive commercially available sediment filters\nproved effective in intercepting all larvae:\nthe Matrikx Accucarb, which uses a carbon\nblock filter. An ongoing study in Jarvi\u2019s\nlab suggests that ultraviolet light systems,\nemployed by many Puna households, may\nnot immediately kill all larvae.\n<\/p>\n\n\n\n

Another daunting problem in the treatment of rat lungworm infection has been diagnosis. Up to now, a definitive diagnosis involves a spinal tap. Jarvi and her colleagues are now working to develop a blood-based diagnosis, which would make diagnosis much simpler. <\/p>\n\n\n\n

Rapid \u2018Ohi\u2018a Death<\/em><\/h4>\n\n\n\n

Researchers and foresters are learning ever more about the ways in which two Ceratocystis <\/em>fungi \u2013 C. lukohia <\/em>and C. huliohia <\/em>\u2013 work once they infect \u2018ohi\u2018a trees. <\/p>\n\n\n\n

Mark Hughes of the University of Hawai\u2018i\u2019s College of Tropical Agriculture and Human Resources described the different mechanisms. The former, which is more quickly fatal to infected trees, is a wilt disease, with the fungus migrating through the tree\u2019s vascular system even before symptoms \u2013 dying crown, dead leaves \u2013 become visible. <\/p>\n\n\n\n

In the case of C. huliohia<\/em>, the disease\ncauses cankers, which eventually spread and\njoin up with other cankers.\n<\/p>\n\n\n\n

Robert Peck of the Hawai\u2018i Cooperative\nStudies Unit at the University of Hawai\u2018i-\nHilo, discussed the role ambrosia beetles\nplay in spreading both diseases. Frass from\nthe beetles, caused when they clear out the\ntunnels they bore in the trees, can carry\nthe spores of Ceratocystis<\/em>. Those spores,\nhe noted, are sticky and while not able\nto become windborne on their own, they\ncan attach to frass. Peck and his colleagues\nfound viable fungus in frass from the very\ntops of some trees.\n<\/p>\n\n\n\n

Some of the frass that was collected in environmental samplers showed \u201cfungal structures,\u201d he noted, but none were viable in the lab. Peck was asked whether the long residence time in the samplers \u2013 up to several weeks \u2013 might have caused the spores to dry out and die. Peck acknowledged that possibility, and said more frequent monitoring of the samplers might be needed. <\/p>\n\n\n\n

J.B. Friday, extension forester with the\nUniversity of Hawai\u2018i-Hilo, noted that\nresearch is being done to identify \u2018ohi\u2018a\nthat might be resistant. Also, in very limited\ncircumstances, where a single tree is highly\nvalued, treatment with a fungicide might\nkeep a tree healthy.\n<\/p>\n\n\n\n

But in the meantime, more than a million\n\u2018ohi\u2018a trees have died as a result of rapid\n\u2018ohi\u2018a death, and more than 170,000 acres of\nnative forests have been affected on Hawai\u2018i\nisland alone, he noted. \u201cIsland-wide eradica-\ntion is out of the question,\u201d he said.\n<\/p>\n\n\n\n

Yet much can be done to halt its spread,\nhe said. Quarantine of untreated \u2018ohi\u2018a\nproducts from Hawai\u2018i island, washing\nof trucks and tools, cleaning of boots and\ngear \u2013 all will help in stopping the spread\nof ROD.\n<\/p>\n\n\n\n

Equally important, if not more so, is the need to reduce wounding of \u2018ohi\u2018a trees. \u201cYou need a wound for infection to occur,\u201d he said. To underscore this point, he dis- played a map showing ROD-infected trees in the Kahuku area of Hawai\u2018i Volcanoes National Park. \u201cKahuku has 60 (ROD-) positive trees,\u201d Friday said. \u201cAll are below the fenceline\u201d that surrounds the ungulate-free area. <\/p>\n\n\n\n

A similar map showed the park\u2019s Ola\u2018a\ntract, near Volcano Village. Again, in the\nungulate-free fenced area, no infected trees\nare found.\n<\/p>\n\n\n\n

\u201cFencing, removing the ungulates, protects the forests,\u201d he said. \u201cWe need to protect what\u2019s healthy rather than restore what\u2019s lost,\u201d he concluded. \u201cWe don\u2019t want to go the dry-forest way.\u201d <\/p>\n\n\n\n

\u2014Patricia Tummons <\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

One of the oldest arguments against biological control concerns the introduction of the mongoose to Hawai‘i. True: mongooses were introduced to Hawai‘i in the 1880s by sugar growers who believed they would knock back the problem of rats in cane … Continued<\/a><\/p>\n","protected":false},"author":1,"featured_media":11763,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[458],"tags":[],"class_list":["post-11738","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-september-2019"],"_links":{"self":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts\/11738","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=11738"}],"version-history":[{"count":0,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/posts\/11738\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=\/wp\/v2\/media\/11763"}],"wp:attachment":[{"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=11738"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11738"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/environment-hawaii.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11738"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}