biosecurity

Soil carried on sea freight loaded with dangerous pests and diseases

Soil collected from the external surfaces of sea freight was found to support live microorganisms, worms, seeds and insects, including various regulated biosecurity organisms.

Often introduced unintentionally by human activities, invasive alien species can outcompete and overwhelm native flora and fauna, driving species to the brink of extinction and disrupting the balance of ecosystems. Understanding why exactly they establish in new locations and how they got there in the first place is crucial if we are to mitigate their destructive effects. Unfortunately, there isn’t enough research on this, and the answers might not always be straightforward.

A research team from AgResearch and Better Border Biosecurity (B3) investigated the biological risk posed by soil on the external surfaces of sea freight such as shipping containers or used machinery at sea ports in New Zealand. With their work, the researchers hope to facilitate the assessment of relative biosecurity risks between different introduction pathways and contribute to the development of more efficient measures against them.

The team found soil on most types of sea freight, irrespective of origin, with all soil likely to vector microbes, including plant pathogens. The amount of soil recovered from a single sea container was 5.3 kg, while the overall mean weight collected from sea freight was 417g, with most of the soil found on the underside of sea freight.

“While the presence of soil is perhaps not surprising, the presence of live bacteria, fungi, worms, seeds and insects associated with the soil was of greater concern. Various regulated biosecurity organisms were recovered from the samples, including plant-parasitic worms, seeds, insects and spiders that were not recorded as being present in New Zealand,” says Mark McNeill of AgResearch, who led the study.

Seeds of *Euphorbia prostrata*, a new record to New Zealand, were found on sea freight. Photo by Stefan.lefnaer under a CC BY-SA 4.0

“Not only does the spread of exotic species through these networks represent significant environmental, economic and social costs to natural and agricultural environments if invasive alien species were to establish, a loss of biodiversity is also an expected consequence of invasive alien species establishment. For islands, the implications can be significant, as they have high levels of endemism and invasive alien species establishment can lead to extinction of species as well as biodiversity declines,” the researchers write in their paper, which was published in the open-access journal NeoBiota.

Compared to a previous study on contaminated footwear carried in luggage by international airline passengers, the number and diversity in soil on sea freight was smaller than soil transported in more protected environments (e.g., footwear in luggage). This showed that biosecurity risk can vary with pathway. However, prioritising one soil pathway over another according to the risks they present, and differentially allocating resources is problematic, because the relative risk is dynamic, dictated by factors such as new pests or diseases entering the respective pathways.

Unwelcome guests: International tourism and travel can be a pathway for introducing invasive species

Even so, the researchers suggest that contaminated sea freight is an important introduction pathway for exotic species. The establishment of such species can be prevented by cleaning containers prior to departure, inspection at the border, and further cleaning where required.

Research article:

McNeill MR, Phillips CB, Richards NK, Aalders LT, van Koten C, James TK, Young SD, Bell NL, Laugraud A (2023) Defining the biosecurity risk posed by soil found on sea freight. NeoBiota 88: 103-133. https://doi.org/10.3897/neobiota.88.98440

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Hundreds of weeds found illegally advertised online in Australia

A research team led by Jacob Maher discovered thousands of online advertisements for weeds that are prohibited in Australia due to their harmful impact on the country’s environment and agriculture.

Hundreds of weeds have been found advertised on a public online marketplace in Australia. Cacti and pond plants were among the most frequently advertised illegal weed species. These weeds are prohibited in Australia due to their harmful impact on the country’s environment and agriculture. Despite this, a research team led by Jacob Maher discovered thousands of online advertisements for these weeds. Their study is published in the open access journal NeoBiota.

Water hyacinth, a notorious invader that was found traded online.

Trade of ornamental plants, the kind grown in homes and gardens, is the major way weeds are introduced to new places. Some ornamental plants can make their way into the environment and become invasive, negatively impacting native species and agriculture. Increasingly, plants are traded on the internet, allowing a wide variety of plants to be introduced to more distant places. A lack of surveillance and regulation of this trade has resulted in the wide trade of invasive species.

In response, scientists from the University of Adelaide have utilised specialised software called ‘web scrapers’ to monitor trade on public classifieds websites. These web scrapers automate the collection of online advertisements. This allowed the researchers to detect thousands of advertisements for weeds over a 12-month period.

Opuntia, a notorious invader that was found traded online.

Despite Australia’s laws banning the trade of harmful weeds, advertisements were observed across the country. Some of the weeds advertised were associated with uses by traders, including food and medicine. The most popular uses were associated with pond and aquarium plants such as filtering water and providing fish habitat.

The researchers recommend that governments adopt web scraping technology to assist in regulating online trade of plants. They also highlight increasing public awareness and seeking cooperation from online marketplaces as solutions to this growing problem.

“Currently, these online marketplaces allow people to advertise and purchase invasive species, whether they are aware of it or not,” says Maher. “Regulation is needed, but we also need to cultivate awareness of amongst plant growers of this issues and we need help from marketplaces to regulate trade on their end.”

The technology developed in this study is now being utilised by biosecurity agencies in Australia to monitor and regulate the illegal trade of plants and animals online.

Original source:

Maher J, Stringham OC, Moncayo S, Wood L, Lassaline CR, Virtue J, Cassey P (2023) Weed wide web: characterising illegal online trade of invasive plants in Australia. NeoBiota 87: 45-72. https://doi.org/10.3897/neobiota.87.104472

New species of parasitic wasp associated with soybean pest in Minnesota

“It’s really exciting to discover a new parasitoid species in such an important crop system.”

MINNEAPOLIS/ST. PAUL (05/11/2023) — Researchers at the University of Minnesota have discovered a new species of tiny parasitic wasp that might prove beneficial to managing soybean gall midge, a recently emerged pest in Midwest soybean fields that can have devastating impacts on plant production.

Their findings were recently published in the Journal of Hymenoptera Research.

Since the appearance of the midge in 2018, growers have struggled to manage this insect, prompting researchers to seek effective and environmentally-friendly ways to help soybean farmers protect their crop. One approach is biological control, using natural enemies to kill pests. However, because soybean gall midge is new, very little is known about which species might prove to be good allies to growers in the fight against this damaging insect.

Soybean Gall Midge (Resseliella maxima). Photo by jyhmml used under a CC BY-NC 4.0 license.

Amelia Lindsey, an assistant professor in the Department of Entomology, and Robert Koch, an associate professor in the Department of Entomology and an Extension entomologist, led the team at the University of Minnesota. They focused on searching for parasitoids — insects that lay their eggs in or on another insect — of soybean gall midge. Juveniles of the parasitoid develop inside the other insect, eventually killing them.

To find such parasitic insects, a graduate student in the Lindsey and Koch labs, Gloria Melotto, collected soybean gall midge-infested plants from a Minnesota farm and waited to see which adult insects emerged from the plants.

The researchers found:

In addition to a lot of soybean gall midges, there were a number of tiny parasitoid wasps.
In collaboration with two taxonomists who specialize in this group of insects—Jessica Awad, doctoral researcher, State Museum of Natural History Stuttgart, and Elijah Talamas, Florida Department of Agriculture and Consumer Services—it became clear that there was no information on this wasp anywhere in the scientific record. It is a new-to-science species.
The team used DNA sequencing data and physical characteristics of the wasps to formally describe the specimens and give them a scientific name: Synopeas maximum.
The findings point toward this newly described parasitoid wasp species being a likely natural enemy of soybean gall midge.

“Unidentified and undescribed parasitoid micro-wasps are all around us. Although they are tiny, they play a huge role in regulating the populations of other insects, including pests. It’s really exciting to discover a new parasitoid species in such an important crop system,” said Awad.

“Effective management of soybean gall midge has proven challenging. Identification of a new species of parasitic wasp attacking this pest is an exciting breakthrough,” said Koch.

Ongoing work from the team includes a deeper dive into the biology of the wasp and the soybean gall midge to see how often this wasp attacks the pest, and how widespread this potential beneficial insect is across the midwest. Ultimately, the goal is to develop strategies for incorporating the natural enemy into management plans for safe and effective control of soybean gall midge infestations.

This research was supported by the Minnesota Rapid Agricultural Response Fund.

This research brief was originally published by the University of Minnesota Twin Cities. We republish it with their permission.

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Naturalists can mediate silent plankton invasions

Plankton can easily spread between water bodies on hydrobiological instruments if naturalists use inadequate biosecurity treatments in their work.

Homo sapiens is not only a great (perhaps the best) candidate for the world’s most invasive species award. Humans, due to their actions and technological wonders, are also at the forefront of good vectors for organismal dispersion. Can we break this inglorious streak?

“Because humans will continue to interact with terrestrial and aquatic environments, it is impossible to stop the human-aided dispersal of organisms completely. The best we can do is minimise the risk of human-mediated organism dispersal events by implementing adequate biosecurity methods in our activity” explains Dr Wejnerowski from Adam Mickiewicz University (Poland).

Plankton sampling using net. Photo by Sandra Wejnerowska

“We should be aware that all our activities can affect biodiversity, and adequate biosecurity treatments should be applied whenever the risk of inadvertent spreading of organisms is non-zero” adds Dr Marcin Krzysztof Dziuba from the University of Michigan (United States of America).

Recently, a team of researchers from Adam Mickiewicz University, Istanbul University (Turkey), Åbo Akademi University (Finland), and the University of Michigan empirically proved that plankton net – a basic hydrobiological instrument of almost every aquatic scientist and water manager – is a good vector for the dispersal of various phyto- and zooplankton taxa, including species of high invasive potential. Nuisance, bloom-forming, also toxic filamentous cyanobacteria are efficient hitch-hikers, and they are able to successfully compete with native residents in the new environment.

Instructions for US citizens to avoid spreading invasive species during lake recreation. Photo by Marcin Krzysztof Dziuba

Apart from identifying hitch-hiking plankton on the net and its fate in the new environment, the paper they published in the journal NeoBiota also describes the most commonly used biosecurity treatments that naturalists worldwide use to prevent plankton spread between water bodies via the net.

Their findings sound disturbing: naturalists use inadequate or questionable biosecurity treatments. As revealed by the survey data, only 9% of plankton samplers clean plankton nets using disinfectant liquids after sampling, while a majority of people either rinse the net with distilled or tap water, immerse the net with an open outflow in the water body and let it dry, or do not care about the cleanness of the net after sampling at all.

Exemplary photos of some phyto- (A – Limnothrix redekei, B – Planktothrix agardhii, C – Pseudanabaena limnetica, D – Melosira varians, E – Desmodesmus armatus, F – Asterionella formosa, G – Tetradesmus obliquus) and zooplankton ( H – Keratella cochlearis f. typica) hitch-hikers on the plankton net. Micrograph I shows the plankton biomass on the surface of the plankton net after immersing the net with an open outflow in the water body (inadequate biosecurity treatment). Photos by Tumer Orhun Aykut and Łukasz Wejnerowski. Identification of organisms by Aleksandra Pełechata and Marcin Krzysztof Dziuba.

“Indeed, the reality presented in the paper is unsettling. It worries me when I think of how often I have accidentally facilitated dispersion of nuisance plankton and how much I contributed to the invasion of plankton taxa into new water bodies when using inappropriate biosecurity treatments in my fieldwork,” admits Dr Wejnerowski, and adds: “We do not mean to reinvent the wheel; the problem of aquatic organism dispersal through hydrobiological instruments is already known. For years, it was neglected despite some recalls from the scientific community. It comes back like a bad penny because it needs a complex solution from the society of aquatic naturalists. It should happen. After all, naturalists are a human line of defence, protection and rescue for nature.”

Research article:

Wejnerowski Ł, Aykut TO, Pełechata A, Rybak M, Dulić T, Meriluoto J, Dziuba MK (2022) Plankton hitch-hikers on naturalists’ instruments as silent intruders of aquatic ecosystems: current risks and possible prevention. NeoBiota 73: 193-219. https://doi.org/10.3897/neobiota.73.82636

Unwelcome guests: International tourism and travel can be a pathway for introducing invasive species

International tourism can facilitate the dispersal of exotic species. A new analysis of data from tourism accommodations and exotic organism detections in New Zealand, published in NeoBiota, shows that levels of detection significantly correlated to international and domestic tourist movement, even with population levels taken into account. There was no detectable difference between the risk from international and domestic tourists, indicating that tourism as an activity correlates with the introduction and spread of exotic species.

Tourists, albeit unwittingly, may help such unwanted organisms spread further and conquer new lands – they can carry them over in their luggage or on their clothes and shoes. In 2011, a study from New Zealand found that, for every gram of soil on the footwear of aircraft passengers arriving from abroad, there were 2.5 plant seeds, 41 roundworms, 0.004 insects and mites, and many microorganisms, such as fungi that could cause plant diseases. Moreover, these organisms were alive, and some of them were known to be biosecurity threats. Importantly, tourism can introduce risk in two directions, namely from the arrival of international travellers and also the return of residents from international travel.

An important question, then, is to what degree they play a role in the spread of exotic organisms. A study, carried out by Dr Andrew Robinson of the Centre of Excellence for Biosecurity Risk Analysis at the University of Melbourne and Mark McNeill of AgResearch New Zealand, looks to answer that question.

To do so, the researchers compared data on the interceptions of exotic organisms in New Zealand against accommodation data for international and domestic tourists, factoring for the country’s population distribution. The study, recently published in the open-access journal NeoBiota, covered the period between 2011 and 2017, and the exotic organisms that were detected included insects, spiders, mites, snails, plants, and roundworms.

Robinson and McNeill found a significant relationship between levels of incursion detection and tourism accommodation records: the number of nights spent in hotels significantly correlated to the detection of exotic pests for that period. Importantly, the study found no significant difference between the effect of international and domestic tourism, proving that even travel within the country can facilitate the spread of exotic species. A significant positive correlation was also found between the detection of exotic organisms and population numbers across different regions.

“The core take-home message is that within-country tourism movements are significantly correlated to the detection of exotic pests,” the researchers explained. That is, tourists and returning residents bring bugs in, and both are implicated at spreading them once they are in the country. They suggest that biosecurity authorities should continue allocating resources to the management of invasive species and pests that get carried around by tourists and their activities.

However, they also point to the biosecurity risk posed by other possible pathways for of exotic organisms, such as sea freight. A comparison between the different ways of introduction and dispersal would provide a better understanding of relative risk, they conclude.

Research article:

Robinson AP, McNeill MR (2022) Biosecurity and post-arrival pathways in New Zealand: relating alien organism detections to tourism indicators. NeoBiota 71: 51-69. https://doi.org/10.3897/neobiota.71.64618

Australia’s wish list of exotic pets

In a new study, published in the peer-reviewed open-access scholarly journal Neobiota, scientists estimated the desire of Australians to own non-native and/or illegal alien pets and the major trends in this practice. In addition, the team suggests ways to improve biosecurity awareness in the country.

Juvenile green iguanas for sale at Repticon Trading Convention 2018 in Palm Springs, Florida
Photo by Adam Toomes

Unsustainable trade of species is a major pathway for the introduction of invasive alien species at distant localities and at higher frequencies. It is also a major driver of over-exploitation of wild native populations. In a new study, published in the peer-reviewed open-access scholarly journal Neobiota, scientists estimated the desire of Australians to own non-native and/or illegal alien pets and the major trends in this practice. In addition, the team suggests ways to improve biosecurity awareness in the country.

Over the last two decades, Australia has been experiencing an increased amount of non-native incursions from species prominent in the international pet trade, such as rose-ringed parakeets, corn snakes and red-eared sliders. On many occasions, these animals are smuggled into the country only to escape or be released in the wild.

In general, the Australian regulations on international pet trade are highly stringent, in order to minimise biosecurity and conservation risks. Some highly-desirable species represent an ongoing conservation threat and biosecurity risk via the pet-release invasion pathway. However, lack of consistent surveillance of alien pets held, legally or otherwise, in Australia remains the main challenge. While there are species which are not allowed to be imported, they are legal for domestic trade within the country. Pet keepers have the capacity to legally or illegally acquire desired pets if they are not accessible through importation, and the number of such traders is unquantified.

Since keeping most of the alien pets in Australia is either illegal or not properly regulated, it is really difficult to quantify and assess the public demand for alien wildlife.

A juvenile ball python for sale at Repticon Trading Convention 2018 in Palm Springs, Florida
Photo by Adam Toomes

“We obtained records of anonymous public enquiries to the Australian Commonwealth Department of Agriculture, Water and the Environment relating to the legality of importation of various alien taxa. We aimed to investigate whether species desired in Australia were biased towards being threatened by extinction, as indicated by broader research on pet demand or towards being invasive species elsewhere, which would indicate trade-related biosecurity risks”,
shares the lead author Mr. Adam Toomes from the University of Adelaide.

According to the research team’s analysis, pets desired by Australians are significantly biased towards threatened species, invasive species and species prominent in the U.S. pet trade.

“This novel finding is of great concern for biosecurity agencies because it suggests that a filtering process is occurring where illegally smuggled animals may already be “pre-selected” to have the characteristics that are correlated with invasive species,”
warns Mr. Adam Toomes.

However, the bias towards species already traded within the U.S. suggests that there is potential to use this as a means of predicting future Australian desire, as well as the acquisition of pets driven by desire. Future research from the Invasion Science & Wildlife Ecology Group at The University of Adelaide will investigate whether Australian seizures of illegal pets can be predicted using U.S. trade data.

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Original source:

Toomes A, Stringham OC, Mitchell L, Ross JV, Cassey P (2020) Australia’s wish list of exotic pets: biosecurity and conservation implications of desired alien and illegal pet species. NeoBiota 60: 43-59. https://doi.org/10.3897/neobiota.60.51431

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Survival of soil organisms is a wake-up call for biosecurity

Tiny creatures in soil that attack plants have shown the ability to survive for at least three years stored in dry conditions in a recent AgResearch study, giving new insights into the biosecurity threats posed by passenger travel and trade between countries. The research article is published in the open access journal Neobiota.

The findings of the study also add to the discussions about how best to detect these creatures, called nematodes, before they cross borders and potentially reduce yields of important crops and pasture.

Nematodes are very small worm-like organisms. They can be extremely hardy and can have both beneficial and detrimental impacts. The harmful ones, the plant parasitic nematodes (PPN) include species that attack plants reducing their growth and survival.

In the study, funded by AgResearch via the Better Border Biosecurity collaboration, soil collected from a native forest and an organic orchard was stored separately in cupboards at room temperature for a period of 36 months.

Samples were then taken at regular intervals to see if any nematodes could be recovered from the soil and, if they could, whether they were able to infect plant hosts.

“In the study we used different methods to detect nematodes — including a water misting technique to draw them out of the soil, and a baiting method — where we grew white clover and ryegrass plants in pots containing a soil sample,” explain the authors.

“One of the PPN we looked at was the root lesion nematode. What we found was that lesion nematodes were able to successfully invade the roots of ryegrass even after 36 months,” says AgResearch nematologist Lee Aalders.

“They were also able to produce offspring at 13 months. Interestingly, no PPN were recovered from soil stored beyond the 13th month using the three-day misting technique.”

This means that given the right conditions, PPN in soil, which is carried on sea freight, footwear or used machinery, and protected from sun or extreme heat, will survive if they end up near a suitable host plant. This is a result that may not be detected using an extraction test like misting.

For quarantine officials around the world, this result is an important find, as it reinforces the risk associated with soil that, even though it may look sterile, unwanted nematodes may be present and undetected until paired with a suitable host plant.

“In the context of biosecurity, we think that the development of a generic test for plant parasitic nematodes – based around a molecular based bioassay — would enhance the probability of detection of PPNs and, therefore, prevent unwanted incursions beyond the border.”

Earlier this year, another AgResearch study into the survival rates of various transported soil organisms and published in Neobiota concluded that biosecurity risks from soil organisms are to increase with declining transport duration and increasing protection from environmental extremes.

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Original source:

Aalders LT, McNeill MR, Bell NL, Cameron C (2017) Plant parasitic nematode survival and detection to inform biosecurity risk assessment. NeoBiota 36: 1-16. https://doi.org/10.3897/neobiota.36.11418