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Quarantine Pests

The Importance of Guarding Against Quarantine Pests

In addition to all of the various native pests and imported pest species that currently plague much of Perth and the surrounding environs, there are many other exotic species that are considered to be on the nation’s watch list. For a variety of reasons, these creatures are considered quarantine pests, and need to be reported if anyone suspects that they are present in the area. Many of them are already present in small numbers and very localized areas of the country, while many others have been barred from taking root on the nation’s soil – at least so far.

In most instances, these pests either pose a significant risk to crops, pose an unusual health risk, or have no credible natural predator on this continent to contain their populations. As such, the best way to deal with them is to quarantine the entire species and do everything possible to prevent them from taking root in Perth or anywhere else in the country. Even a small incursion has the potential to result in losses that could cost a community many millions of dollars.

Giant African snails

The snails originate from East Africa, and can grow as large as 200 mm in length. The snail has already found its way around much of the world, and can be found in a wide variety of tropical areas. At present, Australia is considered to be free of this pest, and strict controls are in place to ensure that it is denied a foothold in the country.

This pest is attracted to hundreds of different plants, including legumes and various vegetable crops. It will also attack citrus tree bark, and eucalyptus. As such, it is considered a major threat to horticulture in Australia, since it can devastate a crop in rapid fashion. Worse, they are prolific breeders, with a single hatching involving anywhere from 100 to several hundred eggs. Adults can produce more than 1,000 eggs a year, which means that even a minor incursion could become a major infestation quite rapidly.

The species itself often obtains entry into new locations by attacking itself to machines, cars and trucks, shipping crates, and other items and goods that are routinely shipped from one continent to another. Sometimes, their presence can be identified by the snail trail they leave in their wake. At other times, they get transported as eggs, usually within potted soil. Perth residents who see these creatures – or any large snail that they suspect might be Giant African snails – should immediately contact the Department of Agriculture to report the incident.

Red Imported fire ant

The Red Imported Fire Ant is among the most serious of ant pests around the world. To date, they have been discovered in Brisbane, and are now established throughout the southeast in Queensland. These ants are only about 5mm long, with reddish coloring and a propensity to sting anyone that comes near. Unlike most ant stings, however, the RIFA’s sting causes blisters and pustules that are extremely painful and uncomfortable.

These pests are a real problem in many ways. They form what some call “super-colonies” in which several queens act to spread the size of their colony very quickly. They eat almost anything they can, including invertebrate and vertebrate species, as well as many plant types. They target crops at every stage of growth, consuming everything from newly planted seeds to harvest-ready produce and plants. To make matters worse, they come into direct feeding competition with many native species of insects, thus depriving those creatures of their natural food sources. That can lead to a disruption of the area’s natural ecosystem, and often leads to the destruction of species that are responsible for important functions like pollination.

In places where this invasive species has already become established, thousands of people are treated each year for fire ant stings. Many experienced allergic reactions to the stings that can be life-threatening, while others suffer scarring from the stings’ effects. These pests also cost an estimated $3 billion in damages and control costs each year. They chew electrical wires, telephone lines, and insulation. They can even disrupt the soil to the point where they weaken infrastructure like driveways, roadways, and walls.

They can be equally devastating from an agricultural standpoint. They are so destructive that they can kill citrus trees and potato tubers, and often infest areas with hundreds of their mounds. That can severely limit workers’ ability to tend fields, or subject them to potential attack.

To counter this menace, Australia created the National Red Imported Fire Ant Eradication Program in 2001, with the goal of preventing the species from spreading beyond its current limited range and ultimately eradicating it altogether. As part of that regime, there are currently tight movement restrictions in place on any items that could possibly carry these creatures to new locales.

European house borer

This pest focuses its attention on timber like fir and pine – which means that it is also attracted to the wood used in many building structures. The Department of Agriculture and Food has an entire team dedicated to stopping the spread of the European house borer, to ensure that Western Australia remains as free as possible of this horrible infestation.

The actual adult version of the borer is not the problem, per se. These creatures only tend to live for days, and spend much of that time preparing to lay their eggs. It is those eggs – or rather, the beetle larvae that soon emerge from them – that are the true problem. The European house borer leaves its eggs in dead wood, such as is found in buildings or in the dead branches of living trees. Those eggs hatch larvae that spend anywhere from two to twelve years chewing their way through whatever wood they’ve infested. At maturation, they emerge from that structure, with the adults often laying their own eggs in the same wood source. As several generations feed on that wood over the course of many years, its entire structure can be compromised.

Since the pest’s discovery in Perth in 2004, there have been Restricted Movement Zones in effect to prevent the spread of the creature outside its current zone of influence. These RMZ restrictions limit the types of materials that can be moved out of the Perth region, and have been effective in containing the pest to date.

Electric ant

The electric ant has been on Australia’s pest control radar for roughly a decade, ever since the exotic creature was first discovered in Queensland near Cairn. It is now present in several other areas of the Queensland region as well, but biosecurity efforts have been relatively effective at containing its spread outside of the area.

The creature itself hails from the Western Hemisphere, where is commonly seen in both South and Central America. It has also spread to West Africa as well as many island destinations. It is often compared to the Red Imported Fire Ant, since both species have the same powerful sting and harmful venom. Like those ants, the electric ant gets from one place to another by stowing away on various shipments of goods.

There are tiny creatures, averaging no more than 1.5 mm. They are often found nesting in stones, trees, or vegetation debris, but also make their way into homes where they will infest sleeping beds and furniture. They are also commonly seen in food, including pet food. This places them into direct contact with both domestic animals and humans, either of which they will attack if given the opportunity.

Though they are unlikely to do as much serious damage to crops as many of the worst agricultural pests, these ants are still considered among the worst of the world’s invasive species due to their propensity for attacking humans and animals. These attacks constitute their primary impact on agriculture, as they often attack workers. Even so, they have been known to attack plants as well. Like the RIFA, these ants are strictly quarantined.

Green snail

The green snail is a virulent pest that can do a tremendous amount of damage to many different plants. They attack native plants, grass, and a variety of agriculture crops including cereals and leafy vegetables like lettuce and cabbage. As a result of their damage potential, they are on the quarantine watch list and special effort is made to prevent their spread.

The snails are small in relation to many brown species, and have a white body encompassed by a greenish-colored shell. Their quick reproductive cycle can increase their populations so rapidly that they can quickly expand their numbers to the point where there are many hundreds of young creatures in a given square meter of space. Like other snails, the green snail attacks young leaves, leaving the telltale windowpane effect that so often indicates the presence of this type of infestation. The older snails chew beyond just the surface of the leaves, however, and will consume everything except for the leaf veins.

Mediterranean fruit fly

The Mediterranean fruit fly is often better known as the medfly. It is another of those insects that ranks near the top of every list of destructive agricultural pests, as its impact on any crop can reduce production and leave fruit and other produce completely unsuitable for human consumption. That naturally results in tremendous negative impact on trade.

The adult females of this species penetrate the surface of fruit so that they can deposit their eggs within the meat. The presence of the eggs induces rot, but that’s just the beginning of the problem. Later, when eggs hatch, the young larvae begin to feed on the fruit, consuming the pulp from the inside. Even a small infestation of these flies can result in severe damage to crop yield and a loss of value for producers. Moreover, when infested fruit are discovered, entire crops are often destroyed.

Small hive beetle

The small hive beetle is a major threat to beekeeping operations. These beetles hail from Africa’s tropical and warm temp area, which makes them an ideal fit for other warmer climates such as is found in much of the American south and Australia. It should come as no surprise then that the creature has been discovered in places like Florida in the U.S., and in Queensland, New South Wales, and Victoria in Australia. In all of these locations, the beetle gravitates toward apiaries and disrupts honeybee environments wherever it goes.

These beetles do their damage beginning in the larval stage. They tunnel through honeycomb, damaging the structure of the cells and wax caps as they go. These larvae also feed on the honey and live bees – most commonly consuming the eggs, larvae, and pupae. Their worst effect, however, may be the way in which they befoul the hive. This happens as a result of their tendency to leave their waste directly in the honey. That causes fermentation and frothing that creates a rotten fruit smell. Eventually, the fermentation and various beetle secretions result in slimy hive walls that cause the honey to be unfit for either human or bee consumption.

As might be expected, this has a dire effect on the hive. In some instances, queens simply stop laying eggs. In other more extreme cases, she will take the entire colony and simply abandon their spoiled home. If she remains, the population of adult bees usually declines quite rapidly, as the spoiling of their food causes many to die off. Sadly, even seemingly healthy colonies can be at risk for these infestations, though younger and less stable colonies and hives appear to be at greater risk than more established groups.

Their spread usually occurs through movement of various parts of the hive. They can be present in pollen that has been collected by the bees, in the honey, in beeswax capping, and in other components that would otherwise make up the hive structure. Beekeepers should also be aware that these creatures can be transferred from one location to another on their clothes.

To prevent the spread of this pest, it is important that competent beekeeping practices be put into effect. Note that no pesticides are approved for this purpose, since none are considered safe for the bees themselves. The best defense against this beetle is to adhere to the following beekeeping guidelines:

  • Work to ensure that colonies are as strong as possible. Since the beetle prefers to assault weak hives, it is wise to unite any smaller colonies to create as strong a colony as possible. Before doing so, however, it is important to inspect each colony and its combs to make sure that neither are infested.
  • Care should be taken when adding combs to the hive. Any combs that are not bee-covered will be vulnerable to beetle infestation, so beekeepers should wait until more than two-thirds of all combs are filled before adding new ones.
  • Every effort should be made to limit the amount of time spent opening the hive. This apparently attracts the beetles. Worse, opening the hive can stimulate egg production in any female beetles already inside. That can lead to a rapid expansion of any existing infestation. So, while the hive and colony must be inspected regularly to guard against infestation and other problems, it is vital that great care be taken during any opening.
  • Treat new combs to remove any potential for eggs or larvae before introducing them into the hive. Cold treatment is an effective method for destroying any potential presence of these pests. In fact, research indicates that every stage of the beetle’s life cycle is susceptible to cold temperatures.
  • Locate your hives in direct sunlight whenever possible. These beetles are drawn to the shade and less likely to infest hives in the sun.
  • When the beetle is found in an apiary, beekeepers need to notify the local apiary officer so that the Department of Environment and Primary Industries so that updated records can be kept about the creature’s infestation range. This is required under the dictates of the Livestock Control Act.

Large earth bumblebee

The large earth bumblebee may be an attractive and amazing creature for those who admire such efficient insects, but they are considered a real threat to the ecosystem of Western Australia. Since its illegal introduction on the island of Tasmania, authorities in Australia have been vigilant to the risk that the creature could possibly arrive in Australia either by sea or air travel. To date, only a handful of incursions have been identified – in Western Australia, Queensland, and Victoria.

The main fear of infestation is based upon this species’ potential disruption of the Australian ecosystem, as well as their potential threat to humans and animals. Scientists are concerned that the bees would compete with local honeybees, possums, and birds for the finite supplies of nectar on the continent. Since they are not native to the continent, their pollination attempts on the native flora would likely prove inefficient. Finally, they could focus pollination efforts on various undesirable weeds that are not currently targeted on a large scale by the native bee populations.

These bees are also aggressive defenders of their chosen nesting places. Since those nests often include garden areas and compost heaps, that would place them in direct contact with humans and domestic animals – which could result in increases in multi-sting attacks that can often result in allergic reactions.

Anyone who identifies one of these yellow and black-banded bees should contact authorities to report the sighting so that containment can begin as soon as possible. They can be distinguished from other bees by their furry appearance and larger size, which can reach 22 mm in length for most worker bees. If you plan to deliver the bee to authorities so that it can be examined and properly documented, do so with care to prevent unnecessary injury from its sting.

Queensland fruit fly

The Queensland fruit fly has made major inroads into Australian territory, but has thus far been restricted to Queensland, Victoria, New South Wales, and Northern Territory. In Western Australia, authorities are working to avoid any incursion of this economically-significant pest. To date, those efforts have been considered a success, though vigilance is required to keep the creature at bay.

This fly is considered a major agricultural menace where it has taken root. Its effects are typically seen in dramatic decreases in plant production, and destruction of viable fruit. As might be expected, that destruction comes at a high economic costs for the industries and local economies of affected areas.

Adult flies drop their eggs on punctured fruit, through holes that are so small that most people cannot notice them even when closely examining the surface. These eggs eventually hatch, and larval maggots emerge and begin to eat the fruit’s interior, working their way to the center. As it does so, it grows and eventually chews its way to the surface. Throughout this process, the fruit rots from the inside and typically falls down to the ground. The larvae go into pupa stage in the soil, after which they mature into adulthood and start the process all over again.

European Wasp

Though this wasp species is common throughout the eastern states of Australia, it has not yet made serious inroads into Western Australia Even so, the pest is routinely found entering the state inside various containers and boxes shipped from various locales. To counter those accidental incursions and prevent the creature from gaining a foothold in the region, surveillance and robust system of public reporting efforts are used.

One of the primary problems many people have in identifying this pest is that they are so similar in appearance to insects like the paper wasp. Both are about 15 mm in length, with the same yellow and black markings. At first glance, their bodies are even similar in shape – though closer inspection will confirm that paper wasps are generally thinner than the European variety. Their behaviors, however, clearly separate the two, most particularly when they are in flight.

If you see a wasp flying fairly slowly with its back legs handing down, or hovering near bushes or over various water sources, then chances are that you are observing a paper wasp. They are much slower in flight than the European invaders. The European wasp tucks its legs near its body when it flies, which gives it much greater speed.

European wasps are a serious threat to human health, primarily due to their aggressive nature and tendency to scavenge food. They will consume any meat, fish, or vegetables that are available, and will even go after your pet’s food if you leave it down outside. Because they seek out easily obtainable scraps, they often come into contact with humans and pets, and can become aggressive when they feel threatened. Contrast that with paper wasps, which tend to feed on other live insects, and it is easy to see why authorities consider the European wasp such a menace.

Potato Cyst Nematode

This eelworm is considered a worldwide threat to potato crops, but is especially threatening in temperate areas of the globe. It is believed to originate in South America, and was brought to Europe from that continent more than a century and a half ago. It has been a concern in Australia for three decades, since it was first documented in Munster in 1985. Its impact on potato plants is devastating.

The creature is an extremely tiny wormlike organism that typically grows to be about one millimeter long. It is a soil-dwelling creature that infests potato crops by attacking the roots of the plants. The organism can be difficult to detect, since it exists in the soil not in its worm form, but as eggs contained within the body of a dead female. When planting takes place, these creatures are already present and awaiting the ideal conditions for hatching. That hatching process is caused when potato roots emit certain chemicals into the soil. Shortly after hatching, the young nematodes find their way to those roots and enter the plant cells to feed.

Those infested potato plants end up with stunted growth and wilting, as their root systems are compromised. This results in severe crop yield reductions and can in some instances cause an entire crop to fail. Where infestations occur, the first crop yield usually shows sign of only limited infestation range, with few visible signs that anything is amiss. Subsequent growing seasons will see progressively increased crop damage, as the infestation grows worse over time. While these creatures target potatoes, they will also consume tomato crops and several other plant species.

These nematodes can survive in their cyst form in the soil for up to two decades, which means that an infestation that takes hold in any given area can continue to plague growers for many years to come. Worse, it is easily spread from one area to another through the transport of soil that contains the worms or their eggs. When tubers are harvested, there is often soil remaining on the outside of the potatoes – and egg-containing cysts can be contained within that dirt. The creatures can also be transported by everything from farm tools and equipment to workers’ clothes. To complicate matters even more, the creatures can even be carried to new locations by flood waters and the wind!

Obviously, every effort should be made to control these creatures and prevent their spread. Once they take root in an area, there is no short-term solution for removing them. Prevention is thus the primary goal for all containment efforts, and that requires growers to follow strict farm management practices designed to minimize risk of infestation. Soil should be regularly tested for signs of the pest, growers should rely on certified seed only, and total control needs to be exercised over non-resistant potatoes. Crops should be rotated regularly as well.

Resistant potato cultivars offer the best hope of eradicating the pest. These cultivars have been demonstrated to stimulate hatching rates in which ninety percent of all eggs hatch and invade the plant roots. While that sounds like a bad thing, it is not – largely due to these cultivars’ ability to prevent those hatched nematodes from developing beyond their juvenile stage. That prevents them from maturing and creating new cysts – and effectively breaks the life cycle of those creatures. When the next crop is planted, there will be fewer cysts in the soil to perpetuate the infestation.

Other Creatures of Concern

Various animals can be a cause for concern as well. Some can carry seeds, insect pests, or other quarantine threats on their fur or in their bodies, and thus quarantine inspections are typically made when these animals are brought into the region. Others, like the wild brown rabbit, are barred from entry into Western Australia altogether. Reptiles, amphibians, spiders, and insects must all be declared by anyone trying to bring them into Western Australia so that authorities can determine their safety level and prevent access if the species is considered a threat of any kind.

Feral animals such as the European rabbit, feral pig, and other species have proven capable of disrupting the country’s natural biodiversity. They often destroy crops and land, and many have no natural predators to keep populations in check. That can result in them competing for resources with native species, and distorting the ecological balance in a way that can have long-term negative effects. Various bird and fish species have also proved problematic when introduced into Australia, with species like the rock pigeon and carp proving especially troublesome.

Managing Quarantine Species Threats

The management and prevention of the spread of these invasive species is undertaken in an organized way at both the federal and state level. At the national level, the Australian Quarantine and Inspection Service is charged with identifying threats and working to ensure that none of them enter the country. Those efforts are reinforced at every level of society, through state and local organizations that focus on quarantine efforts, and private organizations and research groups that study, monitor, and report problems when identified.

There is also a concerted scientific effort underway to improve control solutions. At times, this has led to officials introducing one species in an effort to control others. Those efforts have seen both success and failure in recent decades, with the most notable failure being the introduction of cane toads in the hope that the species would control the cane beetle. As many know, the toads ignored the beetles and instead became a pest in their own right.

Most quarantine efforts in Western Australia, however, are focused on preventing the spread of invasive species that have already been identified in other parts of the country. By most estimates, those efforts have been largely successful to date.

If you or someone you know believe that you have discovered the presence of a quarantined species, you should contact the appropriate authorities so that direct action can be taken to contain the threat. If you are unsure about the creature, it may be wise to contact a professional pest control expert so that proper identification can be made in a timely manner. Invasive species are a threat to our shared ecosystem, and every Australian has a responsibility to do his or her part in ensuring that creatures that threaten our biodiversity are effectively controlled.

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