Fear On The Farm

The role of entomological weapons in the modern world is changing as rapidly as the nature of human conflict. Conventional military engagements between uniformed troops equipped with planes and tanks battling to seize control of land have given way to insurgent forces using improvised weapons to attain cultural and political victories. Stealth, sabotage, and subterfuge even the odds. And insects can be an ideal means of waging an "asymmetrical" war.

For decades, military planners assumed that humans were the most likely targets. But 21st-century conflicts with unconventional enemies create different scenarios for security and defense planners. From a terrorist's perspective, American agriculture has the 3 Vs of a good target: valuable, vital, and vulnerable. Food and fiber production accounts for 13 percent of the gross domestic product, a trillion dollars in economic activity, and one in every six jobs in the United States. Without the export of farm products, the nation's trade deficit—which is already dangerously out of kilter—would slide toward catastrophic imbalance. But agriculture means more than material wealth.

Farms are the cultural lifeblood of America. Fields, silos, fences, and barns affirm the nation's most cherished mythology. As is so eloquently expressed by Floyd Horn and Roger Breeze, top administrators in the USDA,

Agriculture in America is a lot more than these statistics. It is cowboys and vintners, and the runners in the pits at the Chicago Board ofTrade. It is bio-technologists, florists, forest rangers, tenant farmers, rural cooperatives and the county fair. It is FFA and 4-H. It is human nutritionists giving us sound advice that could save us billions in health care costs and prevent suffering on a massive scale. Agriculture is a huge part of the American investment portfolio. It is an unequaled "jewel in the crown" of this great nation. It is our great concern that the U.S. agricultural production, processing, and marketing system are more vulnerable than ever to deliberate assault by a wide range of biological warfare agents.1

The bureaucrats and politicians have good reason to worry. For history leaves no doubt that invasive species—whether introduced by accident, ignorance, or malice—have the potential to cause enormous losses to the economic and social well-being of Americans.

From 1906 to 1991, an estimated 553 nonnative organisms successfully settled in the United States, and two-thirds were insects. A complete assessment of the damage done by the invaders has not been attempted, but the 43 insect species for which careful analyses have been conducted account for $93 billion in losses.2 This cost is thought to be more than 20 times that of all other exotic organisms combined. Of course, the insects were—for the most part—attacking crops and livestock rather than humans. But both cunning bioterrorists and foresighted leaders understand that western societies can be grievously damaged without killing large numbers of people, or perhaps any at all. As Shintaro Ishihara, the governor of Tokyo and one of the most influential politicians in Japan, predicted, "The twenty-first century will be a century of economic warfare."

American agriculture is an ideal objective for bioterrorists. The farms and ranches of the United States are virtually unprotected. Some analysts contend that because agriculture is spread across so vast an area, it would be difficult to mount a damaging attack. And this is true if an enemy used nuclear or chemical weapons. But while radioisotopes and nerve gases have half-lives, organisms have doubling times. Simply put, insects disperse and reproduce—and they do so very well.

To make matters still worse, agriculture is a potential target for a frightening array of enemies, both foreign and domestic. Along with the usual suspects— state-sponsored terrorists, rogue states, and religious zealots—comes a gang of other assailants including national and international competitors of industrial agriculture and profiteers hoping to manipulate futures markets. Then we have groups driven by moral righteousness, such as advocates of animal rights; opponents of genetically modified foods; and ecoterrorists concerned with the chemical sins of modern agriculture. And we can't overlook the possibility of organized crime, militias, and copycats getting in on the act.

If it sounds like the list of evildoers is overreaching, consider The Turner Diaries, a source of inspiration for Timothy McVeigh and others of his ilk. This piece of bizarre fiction was written in 1978 by William Pierce, founder of the white supremacist organization known as the National Alliance. The diaries describe a right-wing revolution from within the United States, starting with an effort to shock Americans out their complacency: "[The militia] began appealing to things they [Americans] can understand, fear and hunger. We will take food off their tables and empty their refrigerators." Although this was fiction, there are plenty of actual events to encourage the hopeful terrorist. The real world provides vivid cases in which localized, accidental (as far as we know) releases of foreign insects exploded into full-blown disasters.

The nursing staff was horrified. On the bed lay an elderly patient covered in ants, which had crept through a break in the wall of the nursing home. Most Floridians have heard stories of fire ants attacking newborn animals, but few ever witness these insects killing a fellow human. By the time the staff came to the aid of Mary Gay, the 87-year-old woman had been stung over 1,600 times. The pain must have been excruciating, as fire ants owe their name to the intense burning sensation caused by the venom that they inject. One sting feels like being pricked by a hot needle; hundreds of stings can induce shock. Mary Gay died two days later.3

In the southeastern United States, few creatures are more loathed than the red imported fire ant.4 Ninety percent of residents report that they or someone in their family has been stung by these insects, causing 80,000 people a year to seek medical attention. Nearly a quarter of those stung manifest an allergic reaction. In severe cases, a victim experiences anaphylactic shock, a condition that accounts for the majority of 100 annual deaths from fire ants.

This insect's reign of terror began in 1933, with the arrival of a ship from South America in Mobile, Alabama. At that time, vessels often filled their empty holds with soil from home, and this ballast was emptied along the waterfront as goods were taken aboard. A load of soil from Brazil was apparently seeded with fire ants, which spread into the port city. For many years, the citizens and officials in Alabama were not alarmed. After all, the black fire ant (then thought to be a color variant) had been accidentally brought to the United States in 1918 without causing havoc. Not until nearly 40 years later did entomologists recognize that the black and red imported fire ants were distinct species—and the latter was far more aggressive and invasive. In 1953, the USDA conducted its first survey for this pest and found it had a foothold in ten states. William Buren, the entomologist who named the creature, called this red form Solenopsis invicta, meaning "invincible"—a name intended to reflect his realization that this species would be extraordinarily difficult to defeat. He was right.

By 1997, red imported fire ants had spread throughout the Southeast, infesting 430,000 square miles of land. With each colony capable of producing 6,000 winged reproductive ants each year, there seems to be no stopping the invasion until the species has occupied every potential habitat. Only when the insects encounter conditions that are too cold or dry does the invasion grind to a halt.

A new colony develops rapidly, with the queen laying several hundred eggs each day until the growth of the loamy mound stabilizes after about six months. By this time, there are between a quarter and half a million workers— an area the size of a football field may be crawling with more than 10 million of these insects.

The red imported fire ant is a voracious feeder on both plant and animal tissues. Not only do the foragers consume seeds and fruits of valuable agricultural commodities, but the ant mounds block irrigation systems and make harvesting a nightmare. Wildlife species—particularly amphibians, reptiles, and ground-nesting birds—are ravaged by the fire ants. Livestock are blinded and killed by suffocation when they are stung around the face. In Texas alone, the cost of protecting plants and animals from fire ants exceeds $1.2 billion each year. And various attempts at eradicating the pest with large-scale insecticide applications and cleverly designed biological control programs have only demonstrated that Buren was right—the ant is invincible. But there is another insect pest that makes the fire ant seem like a welcomed visitor at a picnic.

In August 1996, a beetle was discovered in Brooklyn—and this insect's damage potential is estimated at $669 billion.5 For comparison, the terrorist attacks on September 11, 2001, resulted in direct economic losses of $27.2 billion. Millions of urban trees are in the path of the Asian longhorned beetle (Anoplophora gla-bripennis), with nearly half of New York's trees and two-thirds of Chicago's at risk from this wood-boring insect.6 In these two cities alone, tens of millions of dollars have been spent removing lethally infested trees, and there is no end in sight. When urban foresters find the beetles—often in maples, although ash, birch, boxelder, buckeye, chestnut, poplar, sycamore, and willow are vulnerable—the afflicted trees are summarily cut down. Trees have no natural defense against an infestation, and no insecticide can reach the pest once it has tunneled into the wood.

The newly hatched larvae bore deep galleries, where they spend the winter. In late spring, the insect pupates and matures into the adult stage, an inch-long insect with long, graceful antennae. Its jet-black body with white mottling resembles the night sky, giving rise to the alternative common name, the "starry-sky" beetle. The adults emerge from the galleries, feed on the bark of twigs, and reproduce in what is, for insects, a rather modest manner. The female lays only about 80 eggs in her lifetime, but this is plenty to fuel the invasion.

The beetle most likely arrived as a stowaway in wooden pallets or packing crates from China. Although the insect had attacked North American sugar maples in Chinese plantations long before making its way across the ocean, nothing was done to enhance vigilance among inspectors. Once the insect was discovered in the United States, a nationwide quarantine program was established to contain its spread. However, this effort may only delay the inevitable. The beetle larvae are readily transported in firewood and lumber—and with the insect having been found in warehouses in 14 states, it seems only a matter of time before enough beetles slip through our defenses to establish infestations across the country. To make matters worse, unlike many other forest pests, the Asian longhorned beetle attacks healthy young trees as well as old stressed trees.

The wholesale destruction of urban forests to stem the tide of the infestation is a staggeringly expensive proposition. To some, the summary execution of infested trees seems extreme. But the chainsaw is botanical euthanasia, for even if the tree hangs on for a few years it is condemned to a lingering death. And the dying plant is a serious risk to people and property as hollowed-out branches snap off in the wind.

The prognosis for natural forests is similarly discouraging, particularly with respect to economics. The beetles' tunnels degrade the suitability of the wood for lumber or veneer. Even small amounts of damage can halve the value of a tree. The ecological irony of cutting trees to save forests (or at least profits) is a bitter pill to swallow. All of this would be bad enough, but in recent years the longhorned beetle has been joined by an Asian ally—the emerald ash borer (Agrilus planipennis)J

This gorgeous iridescent green insect was first discovered in June 2002 in Michigan, and two years later 15 million ash trees were dead or dying. The initial quarantine seems to be working, but with no means of controlling the pest, foresters are deeply concerned. The cost of removing—let alone replacing—the urban ash trees in the United States is pegged at $40 billion. People don't eat trees, so the damage by wood-boring beetles doesn't raise the specter of crop failures and agricultural disasters. However, other invasive insects ably fill this role.

Few people are in a better position to develop realistic scenarios of bioterror-ism than Lieutenant Colonel Robert Kadlec, who in the 1990s was a member of the U.S. delegation to the Biological Weapons Convention, worked as an inspector with the United Nations Special Commission in Iraq, and taught courses on biosecurity as a professor in the Department of Military Strategy and Operations at the National Defense University. He also is a medical doctor with master's degrees in both national security studies and tropical medicine and hygiene. As such, the detailed, hypothetical cases involving entomological attacks in his analysis Battlefield of the Future make one wonder if Kadlec knows something—maybe a whole lot—more than he can openly share.8

One of Kadlec's intriguing scenarios describes a group of European vintners who are angry over the economic juggernaut of the American wine industry. Posing as tourists, the saboteurs travel to the Napa and Sonoma Valleys. They carry unremarkable canvas bags, filled with maps, sweaters, cameras, and cans labeled as pâté, a most sensible food to complement their numerous tastings. However, rather than containing foie gras, the tins hold thousands of grape lice (Phylloxera vitifoliae)—tiny aphid-like insects that kill vines by infesting and destroying the roots. Moving through the heart of California's wine country, the disgruntled Europeans spread their deadly cargo.

Within a few months, the vineyards begin to show signs of stress, but it is too late to stop the invasion. Carried by wind and water, the insects spread to thousands of acres by the time anyone identifies the problem. Kadlec estimated that such an attack could kill two-thirds of the infested plants and cost the industry at least $1 billion.9

The wine industry is fortunate that the grape louse actually arrived in the United States more than a century ago, when there were few vineyards to fuel a major outbreak. Although the insect has been kept in check, Kadlec's central concern—the vulnerability of American agriculture to foreign insects—is indisputably valid. And while direct insect damage to crops is a serious concern, there is an even greater worry in terms of bioterrorism: the use of insects to vector plant diseases. As the wine industry is now realizing, all of the tactical advantages found with human disease vectors apply to carriers of viruses and bacteria that infect plants.

In 1989, a bizarre insect, native to the southeastern United States, was found in California.10 How it crossed the country is anyone's guess; how it threatens one of the nation's most profitable agricultural industries is increasingly evident. The glassy-winged sharpshooter (Homalodisca coagulata) looks like a bug-eyed, mottled-brown, half-inch toad with clear wings (see Figure 22.1). But its clownish appearance obscures its deadly potential. The sharpshooter sucks up tremendous quantities of plant juices through its strawlike

Figure 22.1. The glassy-winged sharpshooter is the vector of Pierce's disease, a lethal bacterial infection of grapevines. The pest invaded California in 1989; if uncontrolled, the insect-pathogen duo could inflict $20 billion in losses—and with the possibility of the insect-borne disease moving into the state's almond, stone fruit, and citrus orchards, the potential loss to agriculture exceeds the gross domestic product of Costa Rica. (Photo by Reyes Garcia III, USDA/ARS)

Figure 22.1. The glassy-winged sharpshooter is the vector of Pierce's disease, a lethal bacterial infection of grapevines. The pest invaded California in 1989; if uncontrolled, the insect-pathogen duo could inflict $20 billion in losses—and with the possibility of the insect-borne disease moving into the state's almond, stone fruit, and citrus orchards, the potential loss to agriculture exceeds the gross domestic product of Costa Rica. (Photo by Reyes Garcia III, USDA/ARS)

mouthparts. If scaled up to the size of a human, this insect would drink 4,300 gallons of liquid a day, but its voracious feeding is not what terrifies agriculturalists. Rather, this species is the vector of Pierce's disease—a deadly and incurable bacterial ailment of grapevines.

Pierce's disease was first found in California in 1884. However, the local insects were not very effective vectors and growers limited the pathogen to local hot spots for a century. But the glassy-winged sharpshooter dramatically shifted the balance of power in favor of the disease. Within a year of the insect's arrival, thousands of grapevines looked like they'd been scorched. In effect, they were drought stricken, for the bacteria block the water-conducting system within the plant, causing it to die of thirst even if the roots are well irrigated. While the bacteria reproduce at an alarming rate, the same cannot be said for the vector.

The glassy-winged sharpshooter produces only two generations per year, and a female lays perhaps a hundred eggs—a nearly puritanical sex life by entomological standards. Rather than reproduction, this insect's success as a disease vector lies in its catholic diet (more than a hundred different plants), impressive longevity (six-month-old individuals are common), and extensive movement (typically wandering three miles from its birthplace). While Kadlec forecasted a billion dollars in damage in his entomological sabotage scenario, California growers might be delighted if losses from Pierce's disease could be held to this level. Just the rearguard action of protecting vineyards with insecticides amounts to $35 million per year. And if this line of defense fails, infected vines must destroyed and replanted—a process that could cost $20 billion. But there is cause for hope.

The state's quarantine seems, for the moment, to have curtailed the spread of the insect and disease. Meanwhile, releases of tiny wasps (Gonatocerus trigut-tatus) that parasitize sharpshooters' eggs have yielded promising results. In times of war, the enemy of my enemy is my friend—and the stakes are even higher than initially believed. Recent analyses suggest that grapes are just the tip of the agricultural iceberg. If the wine industry's pest-management program fails, this insect-pathogen alliance is likely to attack other agricultural fronts, including California's almond, stone fruit, and citrus orchards—which are worth tens of billions of dollars, not counting the annual value of the harvest.

Being cognizant of the historically devastating consequences of accidental insect invasions and of the prospective struggle against terrorism in the years to come, western nations have begun to seriously consider how they will protect themselves from entomological attack. The driving question for defense departments, agricultural offices, public health services, and intelligence agencies becomes, "What are the most likely targets for a bioterrorist who is armed with a suitcase-full of insects?" Although many agricultural systems would seem to make excellent targets, two examples are sufficient to illustrate the potential of an entomological attack.

Orange juice—it's not just for breakfast anymore. But suppose orange juice wasn't on the table at any meal, or to be more realistic, what if agricultural sabotage reduced retail sales by 50 percent for a period of five years? The economic damage would be staggering: $9.5 billion—or the cost of rebuilding the World Trade Center towers from scratch. And several biological agents have the potential to inflict such losses.

There are half a dozen exotic diseases of citrus that keep orchardists on edge, and all but one are transmitted by insects. A couple of these exemplify the growers' anxieties.11 The bacterial ailment called citrus variegated chlorosis was first reported in Brazil in 1987, where one-third of the 150 million trees in the state of Sao Paulo were infected. Consider that the state of Florida is about the same size, with nearly as many citrus trees. But there is another, more worrisome similarity. Florida already hosts the leafhopper that transmits the disease. The only missing ingredient is an infusion of the pathogen to get the ball rolling.

Florida also plays host to the Asian citrus psyllid (Diaphorina citri), a relative of aphids that, like its cousins, possesses syringe-like mouthparts perfect for injecting microbes into plants. The psyllid arrived in the Sunshine State in the 1990s and has since flourished. While it is a pest in its own right, the deeper concern comes with the recent arrival of citrus greening disease to Florida. Infected trees become yellowed and produce small, discolored, bitter fruits.

As devastating as the losses would be from one of the insect-borne citrus diseases, vast sectors of the agricultural system would be untouched. However, there is another highly vulnerable target whose role in food production is exceptionally pervasive. In this case, rather than insects being the terrorist's weapons, they could become the bull's-eye.

In 1998, a workshop was held in Washington, D.C., to assess food and agricultural security in the United States. Various scenarios were explored by the foremost analysts in the field, and the most twisted but potentially potent tactic was not a frontal assault on fields, orchards, or pastures. Rather, the experts set aside particular crops and asked, "What if a bioterrorist took aim at a fundamental ecological process upon which much of agriculture depends?"

Without insect pollination, 90 different U.S. crops would not yield fruit or seed. Eliminate bees and billions of dollars disappear too. And America's honeybees are sitting ducks.12 Moving easily through unguarded apiaries, an enemy could sprinkle the hives with spores of fungi, including those causing an incurable disease called chalkbrood, which transforms the larvae into mummified lumps of white mold. Bacteria also would make fine weapons, such as the malady called foulbrood, which digests larvae and pupae within their wax cells, leaving a sticky black crust in their place. And the viruses have considerable potential, including Kashmir bee virus, which causes adults to stagger about as if intoxicated as the colony goes into decline. Or a terrorist might introduce a protozoan such as Nosema, which leads to debilitated workers fouling the hive with excrement as the bees suffer from an insect version of dysentery. And finally, a saboteur could easily infiltrate commercial beeyards and release mites, such as those which crawl into the respiratory system of bees and suffocate the insects.

Some of these maladies are already present within our borders and could be spread from infected colonies, but the greater concern is for those ailments that have not been introduced to the United States. Given the vital importance of bees to food production, the mobility of these insects (which would facilitate the spread of disease), the prevalence of commercial and hobby apiaries, and the ease with which one could access the hives, it is no wonder that bees were deemed by the experts to constitute "an inviting and largely unappreciated target."

Farms and ranches across the industrialized world are easy marks for the wannabe terrorist. This situation would be bad enough, but we've managed to paint a bull's-eye on agricultural commodities through our own cleverness. The concern began in the context of human disease. As early as 1969, the United Nations warned governments that diseases that had been eliminated from a region, such as yellow fever from tropical countries or typhus from developed nations, could be reintroduced as biological weapons.13

More recently, public health officials have become concerned that through eradicating smallpox and then eliminating the vaccination program, the human population has become profoundly vulnerable to bioterrorists armed with the virus.14 Of course, obtaining cultures of eradicated diseases is not a trivial matter. Opportunities are far more auspicious when it comes to analogous scenarios with pests of crops and livestock.

The United States is aggressively pursuing a program to rid the nation of the cotton boll weevil (Anthonomus grandis), a pest with an annual price tag of $780 million. But nobody appears to have considered whether boll weevils could become to agriculture what smallpox is to humans—an ideal weapon. This possibility is well beyond mere academic speculation. A parallel case of pest-management success breeding agricultural vulnerability has worried those charged with protecting the U.S. livestock industry.

Even for entomologists who have an affinity for six-legged animals, the New World screwworm is a loathsome creature.15 The species name (homini-vorax) alludes to its appalling diet—hominis means "man" and vorax pertains to "voracious." The screwworm is a man-eater (see Figure 22.2). The insect was named in 1858 by the French physician Charles Coquerel, who noted that this fly was responsible for hundreds of gruesome deaths within the Devil's Island penal colony.

An infestation is seeded by a female fly, who lays a mass of 200 to 300 eggs around a wound. In just 12 hours, the eggs hatch and the larvae begin tearing at the injured flesh with their mouth hooks. The gore of this feeding frenzy

Figure 22.2. The business end of a screw-worm larva, showing the creature's fanglike mandibles that are used to tear the flesh of living, warm-blooded animals. Though it was eradicated from the United States in 1966, a study by the National Research Council revealed that reintroduction of this pest by a bioterrorist would not be difficult and would cost the country tens of millions of dollars. (Photo by John Kucharski, USDA/ARS)

attracts more females as the maggots expand the open sore by the hour. Death almost inevitably results unless the wound is treated—a most unlikely event for a convict on Devil's Island. After five days of feeding, the larvae (by this time, about the size of macaroni noodles) drop to the ground, burrow into the soil, and form pupae. A week later, bluish-green metallic adults emerge, mate, and seek fresh meat. While most people in the 19th century had access to medical interventions that would keep screwworms from eating them alive, livestock were not so fortunate.

As early as 1825, ranchers in the western United States were reporting heavy losses from screwworm infestations. When the insect made its way to the southeastern states in the 1930s, producer profits and animal health went into a precipitous decline. Cattle, horses, sheep, goats, pigs, and dogs were fair game. The navels of newborn animals were often packed with writhing larvae, but any sort of wound rapidly became infested with maggots. Within a week, a pinprick from barbed wire could expand to a couple of inches in diameter, with larvae boring six inches into the animal's body. After another week, the oozing mass of raw tissue might support as many as 3,000 maggots. At this point, the animal was doomed and, if it was fortunate, secondary infection and accumulation of metabolic toxins ended its suffering within another few days. Large animals could be tormented for weeks, but their fate was sealed.

With livestock producers facing annual losses of more than $400 million, entomologists came under tremendous pressure to solve the problem. Edward

Knipling, an influential scientist in the U.S. Department of Agriculture, speculated that screwworms might be controlled through the mass release of sterile males, which would saturate the reproductive capacity of females with fruitless matings. The development of an artificial diet and the discovery that low doses of radiation caused sterility in the flies provided federal scientists with the essential elements to manufacture enormous quantities of infertile males.

A production facility was built in Florida to produce 20 million sterile males a week for a program of aerial dispersal. Beginning in 1958, planes worked their way westward from Florida, systematically distributing 800 flies per square mile to inundate the females with behaviorally lustful, but reproductively worthless, mates. By 1966, the country was declared free of this insect menace and attention turned southward.

To keep the screwworm from returning, the United States joined forces with Mexico. A plant built in Chiapas cranked out half a billion sterile insects a week until screwworms were eradicated from Mexico in 1990. Since then, the United States has extended the no-fly zone progressively southward. A fly factory in Panama ensures that the pest will not make it across the bottleneck between Central and South America. The eradication of the screwworm fly is a spectacular success for the livestock industry—and a golden opportunity for bioterrorists.

According to the USDA's Veterinary Services, a reestablishment of the screwworm to the United States would result in a $750 million annual loss to the livestock industry—not counting the $400 million accrued investment in the current eradication program.16 And American agriculture's vulnerability to this insect was laid bare in a stunning analysis commissioned by the federal government.

A panel of distinguished scientists was asked by the U.S. Department of Agriculture to assess the United States' preparedness for biological attacks. The National Research Council (a division of the National Academy of Sciences) issued a summary of their alarming findings in 2003, but the most worrisome elements were hidden from public scrutiny.17 Prior to releasing the report, the USDA requested that Appendix E be withheld under an exemption of the Freedom of Information Act.18 Despite the government's concern, the concepts in this restricted document have been discussed openly in scientific and policy literature, although some of the details concerning terrorist logistics and targeting criteria of hypothetical attacks are unique.

The text of Appendix E consists of seven scenarios describing attacks on U.S. agriculture, including a case in which bioterrorists release screw-worm flies. The experts imagine an incident beginning with the discovery of screwworm infestations from Florida to California. Such a large-scale synchronized outbreak points to an intentional introduction, a conclusion that the media are quick to grasp and exploit. Newspaper headlines trumpeting the arrival of flesh-eating flies and television footage of maggot-ridden animals are a terrorist's dream come true.

State and federal officials realize that a rapid, coordinated response is essential. With a fly being able to travel 180 miles and deposit 2,500 eggs in its lifetime, the government must immediately quash the hot spots. While entomologists rush to implement control measures, intelligence and law enforcement agencies reconstruct the origin of the attack.

Investigators discover that the perpetrator bribed a worker at a foreign facility that mass-produces sterile male flies. It was a simple matter to sneak screwworm pupae out of the factory before the insects had been sterilized. The terrorist then flew to Miami, smuggling a few quart jars of pupae in his baggage. Driving across the southern United States in a rental car, he seeded feedlots and other aggregations of livestock with his bloodthirsty conscripts.

Meanwhile, according to the hopeful folks constructing the scenario, the government agencies marshal their expertise and suppress the outbreak within a year. Even so, the price tag of the emergency control program is in the tens of millions of dollars, representing an enormous return on the terrorist's investment. Such an attack is entirely plausible, given the state of readiness in the United States.

The National Research Council asserted that the current inspection system makes it unlikely that an intentional introduction would be caught at the port of entry. Despite the council's hopeful claim that sophisticated scientific understanding would be required to pull off an attack, the scenario demonstrates that a saboteur would need only elementary knowledge of the insect's biology and the country's agriculture. As for the government's capacity to effectively suppress a screwworm outbreak, the scientists harbored no illusions that the imagined response was typical of national preparedness.

A rosy ending to the hypothetical attack is plausible only for a well-known insect for which there is already a pest-management program. From this realization, the experts warned that the nation lacks the infrastructure, methods, and knowledge to rapidly detect or suppress intentional releases of most insects. In effect, the screwworm scenario was the exception that proved the rule: the United States is ill-prepared for entomological terrorism.

The situation would be cause for serious concern if the only targets were crops and livestock. But let's face it, a farmer watching his fields wither under an onslaught of insects or a rancher seeing his cattle infested with maggot-ridden sores doesn't evoke near the alarm of a human suffering from a deadly vector-borne disease. And it appears that those responsible for protecting the health of the American people may be no better prepared than the agencies charged with safeguarding the country's food and fiber from terrorists armed with insects.

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