conservation priorities – Page 13 – Center for Invasive Species Prevention

Why doesn’t state government take action to contain pests that threaten to cost 20 million Californians $1,800 apiece?

(The total cost will exceed $36 billion – which will be borne largely by homeowners and municipalities – meaning their taxpayers. The state will bear little of this cost.)

PB036597 fate-sm sm willow tree in Tijuana River riparian area felled by KSHB. Photo by John Boland; used by permission

(To see more scary photos of the damage along the Tijuana River taken by John Boland, go here.

The polyphagous (PSHB) and Kuroshio (KSHB) shot hole borers pose a great threat to many tree species in California – native species in natural and urban settings; non-native species used in plantings; and agricultural crops. Yet the state government is frozen in inaction.

These two shot hole borers attack hundreds of tree species; at least 40 are reproductive hosts. For details, view the write-up here or visit the UC Riverside website here.

Some of the important reproductive hosts for PSHB are listed here; those that are also known to support reproduction of the Kuroshio shot hole borer are marked by an asterisk.

Box elder (Acer negundo)
Big leaf maple (Acer macrophyllum) *
California sycamore (Platanus racemosa)
Several willows (Salix spp.)
Cottonwoods (Populus fremontii & P. trichocarpa)
Several oaks (Quercus agrifolia, Q. engelmannii, Q. lobata)

Several widespread exotic species also support PSHB reproduction: they include the invasive castor bean (Ricinus communis) and widely-planted London plane tree (Platanus x acerifolia).

US Forest Service scientist Greg McPherson has analyzed the vulnerability to PSHB of urban forests in cities in three regions of southern California: the Inland Empire, Coastal Southern California, and Southwest Desert. Together, these comprise 4,244 sq. miles and have 20.5 million residents. Dr. McPherson found that:

1) Approximately 26.8 million trees – 37.8% of the region’s 70.8 million trees – are at risk. Trees at risk include

5 million coast live oaks,
4 million ash,
3 million sycamores and plane trees,
9 million stone fruit or flowering Prunus species,
5 million avocadoes, and
8 million citrus trees.

2) The cost for removing and replacing the 26.8 million trees would be approximately $36.2 billion. This amount averages to $1,768 per capita.

3) The value of ecosystem services forgone each year due to the loss of these trees is $1.4 billion.

4) These estimates are conservative because they:

do not include costs associated with damage to people and property from tree failures, as well as increased risk of fire and other hazards
may undervalue benefits of trees to human health and well-being; and
do not include newly detected host species or the shot borers’ spread.

These disasters are highly likely to occur given the extent of current infestations and difficulty in curtailing spread of the beetle/fungus complex.

Natural areas – especially riparian areas – are also at risk. John Boland reports that 70% of willows studied in the Tijuana River riparian area on the California/Mexico border were infested by KSHB. Tree branches and boles weakened by beetle attack broke in the first winter storms in early 2016. In some sections, “native riparian forest … went from a dense stand of tall willows to a jumble of broken limbs in just a few months.” Trees growing in the wettest parts of the riparian area were most heavily attacked and damaged. Three highly invasive plant species – castor bean, salt cedar, and giant reed – are barely or not attacked by KSHB. The result of the damage to native willows and likely proliferation of the invasive plants is likely to be significant alteration of the entire biological system.

(While no one knows how KSHB reached the Tijuana River, John Boland says there is a greenwaste “recycling” center in the valley. See picture below, taken by John Boland.)

Regulatory action could help protect wildland, rural, and urban forests in the rest of the state – and possibly beyond. Scientists’ analysis of climate indicates that most of the urban and agricultural areas in California are at risk. The scientists have also begun analyzing the potential risk to other parts of country.

Why is the California government so unwilling to tackle a threat of this magnitude?

I have written about this inaction several times as it applies to the goldspotted oak borer. See my blogs on 1) California’s inaction on firewood in July 2015; 2) GSOB and firewood in September 2015; 3) contrasting states’ action on mussels with inaction on firewood posted in December 2015; and 4) the threats to oaks, posted in April 2016.

In October CISP joined an eminent forest entomologist, Dr. David Wood of the Department of Natural Resources at the University of California, Berkeley. We petitioned the California Department of Food and Agriculture to regulate movement of firewood within the state. CDFA refused, saying that the absence of control points through which firewood could be funneled made efforts to regulate its movements impractical. (For copies of our letter and CDFA’s reply, contact me through the “contact” button on the CISP website.)

While there are many questions about practical aspects of implementing and enforcing such regulations, I do not believe they are insurmountable.

I concede that CDFA has provided significant funds for firewood outreach campaigns. But people care about the threat posed by these pests and want CDFA to act. In the meantime, concerned people have formed formal partnerships linking local, county, state, and federal officials and academics to coordinate efforts to manage both GSOB and the PSHB and KSHB. Groups’ efforts can be viewed here and here. CalFire and the California Fire Wood Task Force are active participants.

During a recent conference call sponsored by the California Agricultural Commissioners and Sealers Association’ Pest Prevention Committee, participants reinforced the damaging consequences of CDFA’s inaction:

While scientists are developing new tools for detection of the polyphagous and Kuroshio beetles and the fungi, there are no funds to support their use in a more intensive detection trapping effort!!!!! Call participants discussed various potential funding sources (e.g., from competitive grant programs operated by various agencies). Some survey efforts have been funded – by USDA APHIS:
1. UC Riverside Professor Richard Stouthamer received Farm Bill §10007 funds for two years to develop traps and lures for PSHB.
2. CDFA participates in a national woodborer survey which is funded by APHIS.
In the absence of CDFA designation of PSHB, KSHB, or GSOB as regulated pests, neither state nor county agencies have a firm foundation on which to base regulations to curtail movement of firewood, greenwaste, or other pathways by which these pests can be spread to new areas.

It is clear from the discussion during the call that many people understand the need for regulations to ban movement of firewood out of southern California. But so far they have not succeeded in building sufficient political support to bring this about.

Meanwhile, other federal agencies are beginning to perceive the risk posed by these pests – and are struggling to develop responses. The US Fish and Wildlife Service (USFWS) is trying to develop strategies to protect the forested wetlands, which are habitats for the endangered least Bell’s vireo (a bird) and other endangered species. However, the USFWS lacks funds to carry forward desired detection and other programs. The USFWS offices in California are trying to engage agency leadership on this threat. So far, Endangered Species Act §7 requirements have not restricted removal of infested trees in wetlands already invaded by PSHB or KSHB.

Santa Monica National Recreation Area is the first National Park Service unit to pay attention. I have written in the past that the National Park Service should adopt a nation-wide policy banning visitors from bringing their own firewood to campgrounds (see my blogs from August and October 2015). In the absence of a nation-wide policy, action by individual units is important.

The USDA Forest Service is already engaged, especially with detection and outreach. However, the USFS also does not have nation-wide policy restricting campers from taking their own firewood to campgrounds on National forests.

Many Californians are pushing for action … they need our help! If you live in California, contact your state legislators. If you live elsewhere, your forests are also at risk from the state’s failure to act. So, if you know someone who lives there, ask that person to contact his/her legislators. Ask the legislators to demand state designation of PSHB, KSHB, and GSOB as quarantine pests and adoption of state firewood regulations.

SOURCE:

Memorandum from Greg McPherson, USDA Forest Service, to John Kabashima Re: Potential Impact of PSHB and FD on Urban Trees in Southern California, April 26, 2016

Posted by Faith Campbell

Funding Levels Reveal Low Priority for Combatting Tree-Killing Pests

As the recent article demonstrated, non-native insects and pathogens pose a unique threat to America’s forests. See also my blog posted May 10.

As Scott Schlarbaum and I said in Fading Forests III:

“Ultimately, then, the future of American forests is in the hands of our nation’s people. In choosing our elected representatives, holding other government officials accountable, and making our private choices, we decide the priority of whether addressing the causes and solutions to these pest issues is a priority – and, thus, whether we will keep of our natural heritage. There is already a strong foundation for action.”

However, American society – as reflected in its political decisions – has not put a high priority on countering this threat. We outlined the long history of inadequate funding for USDA APHIS and USFS in chapters III and VI. Also, I wrote about the appropriations process for Fiscal Year 2017 (which begins in October) in my blog posted on March 22.

Recent action by the House of Representatives (see below) might signal a change. We shall have to wait to see whether this change lasts.

APHIS Funding

Too often, we think first of U.S. Forest Service funding as singularly important regarding non-native forest pests and pathogens. When it comes to prevention, though, its USDA’s Animal and Health Inspection Service (APHIS) that is key.

Total funding for the USDA APHIS in FY17 will be on the order of $939 million. The budget for its plant health program is about $310 million. Included in this sum are mere tens of millions for addressing tree-killing pests:

Tree and wood pests — $54 million in the Senate bill, but only $45.9 million in the House bill
“specialty crops” — $167.5 million in the House bill, $158 million in the Senate bill; with only about $5 million likely to be spent on managing the sudden oak death pathogen, especially movement of infected plants, soil, etc. in the nursery trade.

The Center for Invasive Species Prevention and others had requested the higher number for “tree and wood pests”. We think higher funding is appropriate given the number of highly damaging wood-boring insects already in the country – e.g., Asian longhorned beetle; emerald ash borer; redbay ambrosia beetle and its associated laurel wilt pathogen; the polyphagous and Kuroshio shot hole borers and their associated pathogens … (all these species are described here). Furthermore, there is every likelihood that additional pests will be detected in the country since the wood packaging pathways remains leaky (see the Lovett et al. article cited above and my blogs about the wood packaging material pathway posted in July through October 2015).

The House bill specifies that $15 million of the “specialty crops” money should be allocated to citrus pests and pathogens, fruit flies, a grapevine pest and a multi-host pest (light brown apple moth).

USFS Forest Health Funding

Funding levels for the USDA Forest Service also demonstrate a low priority to countering non-native tree-killing insects and pathogens.

Total funding for the USFS is about $5 billion. In making its request for $4.9 billion, the Administration allocated only $92 million to countering threats to forest health (on both federal and non-federal lands).

The House of Representatives’ Appropriations Committee has a different – and welcome – view: the House bill provides $114.6 million for forest health protection. This is $15 million above the FY16 level and $22.55 million above the Administration’s request – a substantial increase unequaled in past years. The accompanying committee report expresses concern about severe insect and disease threats, especially in California. The report also notes that invasive forest pests threaten more than 58 million acres of the Nation’s forests. The Committee encourages the Service to continue its work to assess future risks, control existing threats, research and develop new control methods, and improve the health of forest ecosystems. Since only $5 million of the increase is to be used on non-federal lands, the “bump-up” for non-native pests will be modest.

A note of caution: the House expansion of funding for the forest health program was doubtless made easier by the House’s cuts to programs managed by the Environmental Protection Agency, which is funded by the same bill.)

The Senate bill follows the Administration in allocating only $92 million for forest health protection.

Not only has the Administration asked for less for the forest health program in recent years. The funding allocations within that total trouble me. In the current year (FY16), the USFS allocated only $20.2 million (15% of total forest health funds for this year) to specific projects targeting non-native insects or pathogens. Nearly $10 million of these funds went to just one species – European gypsy moth. The only other species receiving a significant proportion of the funds is hemlock woolly adelgid – HWA received $1.77 million. The second greatest allocation was to oak wilt — $466,000. Ranking third is white pine blister rust, which was allocated $420,000. A group of three species (goldspotted oak borer, thousand cankers disease, and laurel wilt) received a total $587,000. This low figure does not, in my view, reflect the great damage caused by goldspotted oak borer and laurel wilt. Furthermore, I assume that the polyphagous and Kuroshio shot hole borers are included in this grouping, although they are not listed specifically. Both shot hole borers threaten many tree species in southern California riparian areas, and pose a possible threat to trees in other parts of the country. All of these species are expected to receive less funding in FY17 under the Administration’s request. (Again, all these species are described here).

(Native pests – southern and western bark beetles – received a total of $7.2 million in FY16. Invasive plants were allocated $1.7 million. These figures are not included in my calculations in the preceding paragraph.)

USFS Research Funding

The House appropriations bill provides just under $292 million for research – the amount requested by the Administration. The Senate bill cut funding for research to $280 million – a cut of $11 million from the FY16 level. Worse, the Senate also added $2 million to the share of research funding allocated to foerst inventory. The only mention of non-native pests and diseases in the report accompanying the Senate bill is a paragraph instructing the USFS to work with the USDI Fish and Wildlife Service, National Park Service, USDA APHIS, and state agencies to address the threat to the Hawaiian Islands’ `ohi`a trees from the Ceratocystis fungus (the disease is described here). This report emphasizes the importance of continuing research on forest product utilization.

Even more troubling, for years the USFS has allocated only about 3% of its total research budget to research on “pest” species (including invasive plants). Of this total, about half – $5 million – has been allocated to projects targeting non-native insects or pathogens. This year (FY16), the highest funding went to hemlock woolly adelgid, at $1.782 million. The second greatest amount was allocated to emerald ash borer — $1.168 million.

(In FY16, the non-native western bark beetles received nearly $1.4 million in research funding; invasive plants received nearly $1.9 million. Again, these figures are not included in my calculations above. )

USFS Wildfire Funding

One explanation for the Administration’s lower funding requests is the great pressure on the USFS to fund management of wildfire. The agency now spends more than half of its annual budget to fight wildfires. This situation is expected to get worse as the climate warms and fires become even more frequent and intense.

The Obama Administration’s budget proposals for both FY16 and FY17 asked Congress to set up a system to pay the costs of fighting extreme wildfires in the same way it finances the federal response to other natural disasters. When hurricanes and tornadoes cause sufficient damage to be declared disasters by the president, the Federal Emergency Management Agency is authorized to exceed its annual budget and draw on a special disaster account. The account is adjusted each year to reflect the 10-year average cost of responding to such events. President Obama suggested creating a similar exception for USDA Forest Service and Department of the Interior.

Currently, the USFS must obtain funds through annual Congressional appropriations – which are adopted too early for an accurate assessment of that season’s likely fire damage. When fire-fighting costs exceed the appropriation, the USFS must transfer money from other accounts – setting back forest restoration projects and efforts aimed at preventing wildfires.

The Obama administration asked Congress to end the need for such transfers by appropriating 70% of the 10-year average it costs to fight wildfires each year and allowing the Forest Service access to a disaster fund.

However, the Congress has been unwilling so far to establish the disaster fund.

Conclusion

The House bill’s welcome increase for the USFS forest health protection program – if enacted – would address pests that are already widespread. Programs aimed at preventing introductions and responding to newly detected invasions – programs operated by APHIS – do not yet enjoy sufficient support from either the Administration or the Congress.

Advocates for stronger programs to combat non-native forest pests are exploring ways to ensure additional funding for key programs, especially early detection of and rapid response to newly detected outbreaks. You will hear more about these ideas in future!

SOURCES

Descriptions of the Administration’s fire-funding proposal can be found at:

http://www.nytimes.com/2014/02/23/us/obama-to-propose-shift-in-wildfire-funding.html?_r=0&module=ArrowsNav&contentCollection=U.S.&action=keypress&region=FixedLeft&pgtype=article

http://thehill.com/policy/finance/253687-obama-officials-press-congress-to-change-wildfire-funding

Posted by Faith Campbell

When will invasive species get the respect they deserve from conservationists?

i`iwi in Hawai`i

photo from www.TheBirdBlogger.com; used with permission

Evidence is growing that invasive species are among THE major threats to conservation goals worldwide.

In 2015 the IUCN called invasive species the second most significant threat to those World Heritage sites around the world that have outstanding natural values. (Poaching is the greatest threat.) My October 21, 2015 blog showed that the IUCN report actually underestimated the impact of invasive species. I listed briefly the principal invaders in several U.S. National parks. Earlier blogs criticized the National Park Service for failing to regulate the movement of firewood (August 2015) and described the invasive threat to Hawai`i (earlier in October 2015).

Now a second study shows invasive species are a principal driver of species extinction. The authors assessed the prevalence of alien species as a driver of extinctions among plants, amphibians, reptiles, birds, and mammals (which are the best-studied taxa) post-1500 AD. Overall, 58% of extinct or extinct-in-the-wild species had been driven to extinction at least in part by invasive species. Invasive alien species are the second most common threat overall. Indeed, invasive species are the most common threat for vertebrate extinctions (62% of extinct or extinct-in-the-wild species faced threats from invasive species). Invasive species ranked fourth as a cause of extinction for plants: 27% of listed plant species were threatened by invasive species.

For those species with just a single driver of extinction, invasive species is the cause for 47% of mammals, 27% of birds, 25% of reptiles, and 17% of plants. In no case were invasive species identified as the sole threat to an amphibian species – although invasive species are their second highest threat.

Although the paper lists invasive species as second, their threat was virtually identical to that of “overexploitation”, the threat ranked first. That is, 124 out of 215 species studied were threatened at least in part by invasive species; 125 were threatened by overexploitation.

Other principal threats were overexploitation, agriculture, aquaculture, and – in the case of plants – residential and commercial development. Categories related to habitat loss ranked surprisingly low. Only 61 of the 215 cases listed agriculture and aquaculture as threats.

The authors reflect on whether invasive species are not themselves causal agents of extinction, but rather symptoms of the real causes, especially habitat destruction. They conclude that that is unlikely.

Instead, they suggest that invasive species impacts might often be underestimated, as many interactions – especially those between alien parasites and native hosts – are very hard to detect.

Not surprisingly, 86% of island endemic species had invasive species as one extinction driver. Nevertheless, continental organisms are also threatened — 14% of alien-related extinctions have been of species with mainland populations. These include eight amphibians, five birds, and six mammals. Most of these invader-threatened mainland organisms are from the Americas

Among the approximately 30 alien taxa named as extinction drivers are rats, cats, and trout as threats to other vertebrates such as birds and mammals. All three were also ranked highly as damaging invasives in the earlier IUCN report on World Heritage sites. Diseases – especially chytridiomycosis and avian malaria – were causal agents of extinction for amphibians and birds. Several herbivores – especially goats, sheep, and European rabbits – and alien plants were drivers of extinction for plant species.

Of course, outright extinction is not the only damage to biological diversity caused by invasive species. American chestnut, Fraser fir, and redbay are not extinct, but their ecological role has been virtually eliminated as the vast majority of these forest trees die off. Other tree taxa are on same road – ash and eastern hemlocks across wide expanses of their ranges; tanoaks; whitebark pines …

Invasive species pose major threats to biological diversity and other conservation goals. These damages are on top of the acknowledged threat of invasive species to agriculture, forestry, or economic groups. (See, for example, Lovett et al. 2016 discussed in my previous blog.) The role of invasive species in extinction described in this new paper suggest a long-standing bias among conservationists’ priorities. Too often, we have focused on species threatened by overexploitation – which is such easier to see and involves an obvious “villain”.

Nevertheless, a host of practical suggestions have been put forward to address the root causes of species introductions and spread. Often, these ask some or many of us to stop doing what we have been doing. But much meaningful conservation action requires someone to accept limits or to make sacrifices.

Will the conservation community – including grant-making foundations, federal and state agencies, and the many conservation non-governmental organizations ranging from the IUCN to local groups – now take up the challenge of implementing suggested actions and actively advocating for the funding needed for practical steps that will begin to bring this threat under control?

Sources

Bellard C, Cassey P, Blackburn TM. 2016 Alien species as a driver of recent extinctions. Biol. Lett. 12: 20150623. http://dx.doi.org/10.1098/rsbl.2015.0623 http://rsbl.royalsocietypublishing.org /

Lovett,G.M., M. Weiss, A.M. Liebhold, T.P. Holmes, B. Leung, K.F. Lambert, D.A. Orwig , F.T. Campbell , J. Rosenthal, D.G. McCullough, R. Wildova, M.P. Ayres, C.D. Canham, D.R. Foster, S.L. LaDeau, and T. Weldy. 2016. Nonnative forest insects and pathogens in the United States: Impacts and policy options. Ecological Applications, 0(0), 2016, pp. 1–19. DOI 10.1890/15-1176.1

Available at www.caryinstitute.org/tree-smart-trade

Posted by Faith Campbell

Emerald ash borer – crucial research needs funding!

ash tree dying after attack by emerald ash borer

We all know that the emerald ash borer (EAB) has caused enormous damage in the approximately 25 years since it was first introduced to Michigan and Ontario. (For more information, see writeup here. In brief, EAB has killed “untold millions” of ash trees across more than 170,000 square miles in 25 states and two provinces (map).
Apparently all North American ash are vulnerable – more than 20 species in Canada, the U.S., and Mexico. The genus Fraxinus is one of the most widespread on the continent. These trees’ deaths are causing changes in forest species composition, structure, and function. Hundreds of arthropod species that depend on the genus will be affected.

Nevertheless, forests with important ash components are still outside the infested area and deserve greater protection.

Also, ash trees are among the most common ornamental trees planted in U.S. cities and towns. The death of these trees show us that EAB also has imposed billions of dollars in costs on people who had no direct role in the insect’s introduction and spread. Several studies have proposed estimates:
o Communities in Ohio would likely incur costs up to $4 billion if all ash trees on public land were removed and replaced (Sydnor et al. 2007).
o Communities in four Midwestern states would have to pay an estimated $26 billion to remove and replace as trees growing in parks, private lands, and along streets (Sydnor et al. 2011).
o The cost of treating or removing only half of the affected urban and suburban trees across the anticipated range of EAB during the 10-year period from 2009 to 2019 would be $20 billion (Kovacs et al. 2011).

ash tree killed by EAB; Ann Arbor, MI; courtesy of Major Hefje

Over the 14 years since EAB was detected, scientists have learned much about the insect, its hosts, and its management. Early detection of new outbreaks remains difficult. However, traps and lures are more effective than even a few years ago. Other new tools also have been deployed, including strategies for protecting high value trees, and slowing the rate of ash mortality in urban and natural forests.

Four biocontrol agents have been released at sites across the invaded area, although it is too early to know how effective they will be in suppressing EAB populations and protecting ash trees.

The systemic insecticide emamectin benzoate controls EAB for up to three years. This means that municipalities and property owners can now save mature ash trees. Studies show that treating such trees costs less than removing dead trees and planting replacements (Herms and McCullough 2014).

Scientists in Ohio, Michigan, Kentucky, and Massachusetts are testing whether treating just some trees in forest settings can help protect nearby ashes.

One of the most important potential responses to this insect is to breed resistant ash trees. The USDA Forest Service and USDA APHIS have funded such efforts since 2005 – only three years after the insect was detected. Scientists have demonstrated that some ash species that have coevolved with the insect in Asia – especially Manchurian ash – are resistant to EAB attack. More recently, they have been studying how to cross-breed the resistant and non-resistant species and how to evaluate the hybrid progeny for genetic resistance.

Dr. Pierluigi (Enrico) Bonello and others at Ohio State and Wright State University are studying how Manchurian ash trees resist EAB attack. Their focus is on the chemicals present in the trees’ tissues – how they differ in Manchurian ash compared to North American species. These studies have found that Manchurian ash trees contain chemicals that decrease growth and survival of EAB larvae, and decrease the attractiveness of the tree to ovipositing females.
The Ohio team next needs to continue their progress towards identification of the specific chemicals involved, insert the genes that produce them into other ash tree genomes, and produce a large enough number of progeny to test whether the new trees’ genes provide the expected protection.

The team is also studying the other side of this equation – how EAB larvae neutralize defense mechanisms of vulnerable ash species and how these trees may be manipulated to interfere with these adaptations of EAB.. This is a long-term project that needs consistent and sustained support over many years to bring about real capacity for restoring disappearing ash populations.

Unfortunately, funding for this vitally important work is not assured. USDA APHIS (link to 101 on CISP) has funded the team’s work to date, but may no longer be in a position to do so. . After all, it is 14 years since EAB was detected and a decade since APHIS stopped trying to eradicate it. The goal now is to manage EAB in the forest and in urban settings, over the long term. This task logically should fall to the USDA Forest Service.

Both APHIS and the Forest Service are challenged by the need to respond to the introduction of ever more non-native tree-killing insects and diseases; by the need for programs to address pests already present; and by simultaneous reductions in agencies’ budgets. APHIS’ budget for managing all “tree and wood pests” has fallen from $76 million to $55 million since 2011 – a 28% reduction. The USFS’ research budget has fallen less, proportionately: from $307 million to $292 million (a 4% cut).
However, the USFS Research budget has never been generous in funding research on non-native invasive species. Annual totals for invasive species research have been between $5 and $5.6 million since 2012. EAB specifically has been funded at between $1.2 and $1.8 million.
(For a longer discussion of funding shortfalls and other impediments to programs intended to help our forests recover from EAB and other non-native pests, read Chapter 6 of Fading Forests III, available here)

The emerald ash borer is the most destructive and costly forest insect ever introduced to the United States. Surely the government agency responsible for protecting our forests should provide additional resources to counter this threat.

Sources:
Herms, D. A. and D. G. McCullough. 2014. Emerald Ash Borer invasion of North America: History, biology, ecology, impacts, and management. Annual Review of Entomology, Vol 59, 2014 59:13-30.

Kovacs KF, Mercader RJ,Haight RG, SiegertNW,McCulloughDG,Liebhold AM. 2011. The influence
of satellite populations of emerald ash borer on projected economic costs in U.S. communities, 2010–
2020. J. Environ. Manag. 92:2170–81

Sydnor TD, Bumgardner M, Subburayalu S. 2011. Community ash densities and economic impact
potential of emerald ash borer (Agrilus planipennis) in four Midwestern states. Arboric. Urban For. 37:84–89

Sydnor TD, Bumgardner M, Todd A. 2007. The potential economic impacts of emerald ash borer
(Agrilus planipennis) on Ohio, U.S., communities. Arbor. Urban For. 33:48–54
Posted by Faith Campbell

Cacti under Threat – Does No One Care?

Nearly 2 million square miles of ecologically significant and beautiful desert ecosystems straddle the U.S.-Mexico border regions. Cacti are either dominate or are extremely important components of these ecosystems. Two South American insects already present in the United States threaten to kill large numbers of these cacti and transform these desert ecosystems. Iconic species – prickly pears, saguaro, and organ pipe cacti – are at risk.

prickly pear cactus at Factory Butte; photo by S.E. Schlarbaum

Flat-padded prickly pear cacti of the genus Opuntia are threatened by the cactus moth, Cactoblastis cactorum.
In 1989, the cactus moth was found in southern Florida, to which it had spread from the Caribbean islands (Simonson 2005). Since then, it has spread west as far as southern Louisiana. Two small outbreaks on islands off Mexico’s Caribbean coast have been eradicated. If it reaches the arid regions of Texas, it is likely to spread throughout the desert Southwest.
In Florida, the cactus moth has caused considerable harm to six native species of prickly pear, three of which are listed by the state as threatened or endangered. In the American Southwest, at least 80 species of flat-padded prickly pears are at risk (Simonson et al. 2005) and there are more in Mexico, which is the center of endemism for Opuntia.
These cacti support a diversity of pollinators as well as deer, javalina (peccaries), tortoises, and lizards. Prickly pears also shelter packrats –which in turn are fed on by raptors, coyotes, and snakes; nesting birds and plant seedlings. Their roots hold highly erodible soils in place (Simonson 2005).
The U.S. Department of Agriculture began trying to slow the spread of the cactus moth in 2005 – 15 years after it was first detected in Florida (Mengoni Goñalons et al. 2014). However, the program never received an appropriation from Congress so funding was always inadequate. For several years, a patchwork of projects was stitched together: Mexico provided some funding; a volunteer network managed by Mississippi State University monitored lands along the Gulf Coast for the moth; and a laboratory operated by the Florida Department of Agriculture reared moths for research, sterile male releases and biocontrol host specificity testing.
The continuous funding problems led APHIS to abandon its regional program and focus on biocontrol, which is the only viable control measure in the desert Southwest where vulnerable cacti are numerous and grow close together. A newly described wasp, Apanteles opuntiarum (Mengoni Goñalons et al. 2014), is the most promising candidate.
Harrisia cactus mealybug might attack columnar cacti
The 2 million square miles of desert in Southwest United States and Mexico are home to more than 500 columnar cactus species in the Cactoideae (Zimmerman et al. 2010). Some are already endangered; others are totems of the desert, e.g., saguaro, organ pipe, and barrel cacti. The larger ones, particularly, play important ecological roles.
A second South American insect threatens columnar cacti in the Caribbean basin now and in the future could put others at risk in the American Southwest and Mexico: the Harrisia cactus mealybug (Zimmerman et al. 2010).
A mealybug in the genus Hypogeococcus has been killing several of the 13 columnar cactus species in southern Puerto Rico since 2005. Two are endangered species: Harrisia portoricensis and Leptocereus grantianus (USDA ARS). These cacti provide food or shelter for endemic bats, birds, moths and other pollinators (Segarra & Ramirez; USDA ARS). This mealybug is also now killing native cacti on the U.S. Virgin Islands (H. Diaz-Soltero pers. comm. August 2015).
Mealybugs in the same genus in Florida and Hawai`i do not attack cacti (University of Florida fact sheet; Hawai`i Department of Agriculture new pest report). In South America, though, insects in this genus feed on many columnar cacti, including ones in the genera Cereus, Echinopsis, Harrisia, Cleistocactus, Monvilea, and Parodia (USDA ARS; Zimmerman et al. 2010). Scientists are uncertain how many mealybug species are involved, which complicates efforts to determine the level of threat to columnar cacti on the U.S. mainland (H. Diaz-Soltero pers. com. August 2015). No one knows how vulnerable individual cactus species growing in the Southwest are to Hypogeococcus mealybugs (Golubov pers. comm. January 2011). Nor does anyone know whether natural enemies of mealybugs native to Mexico might also attack alien mealybugs and so prevent significant damage to native cacti (Zimmerman et al. 2010).
Still, the possible threat warrants studies to determine the vulnerability of these cacti to non-native mealybugs in the Hypogeococcus genus.
Meanwhile, scientists at the USDA ARS laboratory in Argentina have been searching for possible biocontrol agents but are stymied by the confusion over which mealybugs attach which cacti. Use of DNA sequencing and other tools should clarify these issues (H. Diaz-Soltero pers. comm. August 2015). However, no funds have been appropriated for this work, which has hindered progress (H. Diaz-Soltero pers. comm. August 2015).
To date, no organized constituency has advocated for protection of our cacti from these two pests. In the past I tried to persuade native plant societies, Nature Conservancy chapters, the leadership of the American Cactus and Succulent Society, and other groups that champion the desert to help lobby the Congress to fund USDA’s efforts. I was never successful.
Are Americans truly indifferent to the threat that many cacti in our deserts will be killed by non-native insects? Do they not realize that these threats must be countered before they reach the areas where cacti are dense and numerous?

Sources
California Plant Pest and Disease Report. 2005. Vol. 22 No. 1. Covering Period from July 2002 through July 2005.
Hawaii Department of Agriculture. 2006. http://hawaii.gov/hdoa/pi/ppc/2006-annual-report/new-pest-detections (accessed 11/1/10)
Mengoni Goñalons, C., L. Varone, G. Logarzo, M. Guala, M. Rodriguero, S.D. Hight, and J.E. Carpenter. 2014. Geographical range & lab studies on Apanteles opuntiarum (hymenoptera: braconiDae) in AR, a candidate for BC of Cactoblastis cactorum (Lepidoptera: Pyralidae) in North America. Florida Entomologist 97(4) December 2014
Segarra-Carmona, A.E., A. Ramirez-Lluch. No date. Hypogeococcus pungens (Hemiptera: Pseudococcidae): A new threat to biodiversity in fragile dry tropical forests. {title/org/other identifying information for Segarra-Carmona plus an entry for the pers. comm.}
Simonson, S.E., T. J. Stohlgren, L. Tyler, W. Gregg, R. Muir, and L. Garrett. 2005. Preliminary assessment of the potential impacts and risks of the invasive cactus moth, Cactoblastis cactorum Berg, in the U.S. and Mexico. Final Report to the International Atomic Energy Agency, April 25, 2005 © IAEA 2005
USDA Agriculture Research Service, Research Project: Biological Control of the Harrisia Cactus Mealybug, Hypogeococcus pungens (Hemiptera:pseudococcidae) in Puerto Rico Project Number: 0211-22000-006-10 Project Type: Reimbursable
Zimmermann, H.G., M.P.S. Cuen, M.C. Mandujano, and J. Golubov. 2010. The South American mealybug that threatens North American cacti. Cactus and Succulent Journal. 2010 Volume 82 Number 3

Posted by Faith Campbell