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Improving lives by solving problems in agriculture and the environment

Controlling invasive species

Controlling invasive species

Invasive species, such as weeds, animals and microorganisms are a major issue – threatening ecosystems, habitats and other species when they become established and spread. Many of the species that cause problems are non-native, so we focus on helping to manage these. To understand the impact of invasive species, take a look at our online brochure. 

What are non-native invasive species?

Globalization, climate change and human mobility have fundamentally altered the biological world in which we live. As a result of travel, transport and tourism species have been moved into new environments, where many have established and proliferated.

A species can become invasive when it’s moved from its native ecosystem to a new one. This can be accidental, for example if seeds ‘stow away’ when products are exported from one country to another, but species are also introduced intentionally, because of their perceived benefits. Because they arrive with few or no natural enemies they are often more competitive than the native species, meaning that the non-native species thrive whilst native species suffer.

Why are invasive species a problem?

Invasive species are a global problem. As well as threatening biodiversity, invasive species cause economic losses, and also have an impact on human health and livelihoods.

When a non-native weed species becomes invasive, it can take over grazing land and out-compete crops for limited resources. This can significantly affect yields and production as can insect pests and diseases. Invasive species can also harm the health of people in infected areas: some invasive insects are linked to the spread of diseases, while plants such as ragweed release allergens into the air and are linked to severe hay fever.

What are the options for managing invasive species?

Controlling invasive species can be problematic as chemical and mechanical management options are often ineffective in the long-term, impractical, prohibitively costly, or even illegal.

Biological control is a sustainable alternative way of controlling invasive species. It uses natural enemies of the invasive species, which pose no threat to the new ecosystem and represent a long-term and effective management option.

Prevention is more cost efficient and easier than control. Effective prevention and management requires international cooperation and action. National governments can limit the movement of invasive species across borders through proper quarantine regulation and inspection, and by ensuring food supply chains follow appropriate sanitary and phytosanitary measures.

We’ve been working on invasive species for over 100 years, and we develop workable approaches to tackle the biggest threats.

As well as supporting farmers and smallholders in managing their crop health issues, and promoting efficient farming methods, CABI scientists are world leaders in biocontrol research. We investigate a range of major invasive species problems around the world, the impacts they have and provide solutions. We also advise governments on invasive species policy, and produce books and tools for environmental managers, researchers and farmers on this global issue.

CABI is well positioned to help achieve the Global Goals by 2030 and this means focusing on the impact of invasive species to livelihoods. We have a specific website for this and we want to raise this issue with donors and potential partner organizations around the world. The website includes impact stories, species information and what we're doing.

CABI's invasives blog provides you with stories about our research and debates on topical issues in the field of invasive species from CABI's scientists from around the world.

Biological control of brown marmorated stink bug

International trade is a common way for insects to ‘hitch-hike’ their way to new countries. The brown marmorated stink bug, originally from East Asia, has become a harmful invasive pest of many fruit and vegetable crops in North America and Europe. Biological control using Asian or European natural enemies may be an environmentally friendly,... >>

Controlling noxious Russian knapweed in the North America

Russian knapweed is one of several invasive plants of rangelands that arrived in North America as a seed contaminant in the 19th century, in this case from Asia. Biological control is often a good approach for these plants, but a nematode species introduced in the 1970s proved ineffective against Russian knapweed. Funded by a US and Canadian... >>

Locating a biological control for tutsan in New Zealand

Tutsan, native to Europe, was introduced to New Zealand but is now a major invasive species. In 2011, CABI’s Swiss centre was approached by Landcare Research to investigate prospects for the biological control of tutsan. Surveys in the native range revealed a suite of insects and pathogens. CABI’s laboratories in the UK are currently conducting... >>

Azolla control

One of the UK’s most invasive plants, the fairy fern or floating water fern causes problems for anglers and water managers. It forms thick mats on the water’s surface which can double in size in a few days, blocking out light and killing aquatic flora and fish. Fragmentation of the fronds makes control by mechanical means virtually impossible.... >>

Controlling wild ginger

Plants from the Hedychium genus are widely loved and cultivated as ornamentals but a few are threatening delicate ecosystems in Hawaii, New Zealand, the Macaronesian Archipelago (Azores, Madeira and the Canaries), Brazil, Australia and La Réunion. We are researching natural ways to manage the plants where they have become invasive, which involves... >>

Biological control of Himalayan balsam

Himalayan balsam has rapidly become one of the UK’s most invasive weed species. A lack of natural enemies allows it to successfully compete with native plants for space, light, nutrients and pollinators, reducing biodiversity and contributing to erosion. Traditional control methods are inadequate. This project involves identifying an insect or... >>

Establishing the psyllid: field studies for the biological control of Japanese knotweed

Japanese knotweed is highly damaging. It spreads extremely quickly, preventing native vegetation from growing and has significant impacts on infrastructure. Current control methods rely mainly on chemicals. Research however has identified a tiny psyllid from Japan as a suitable and safe agent to control Japanese knotweed in the UK. The current aim... >>