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Improving lives by solving problems in agriculture and the environment

Impacts of invasive species

Impacts of invasive species

Economies icon

Economies – Invasive species are costing a fortune – both directly, through attempting to control them, and indirectly through lost resources and devaluing land.

Losses caused by invasive species on just eight staple crops are nearing $12.8 billion per annum.

Safety icon

Health – Invasive species can have severe impacts on human and animal health. The allergenic pollen of common ragweed's (Ambrosia) impacts are well known, giant hogweed's toxic sap can cause burns to skin, and opuntia's thorns cause abscesses in the stomachs of the livestock who eat them.

Biodiversity icon

Biodiversity – Invasive weeds crowd out native vegetation and limit plant and animal species diversity. Some invasive plant species can reduce native plant richness by up to 90%.

Water icon

Water and fisheries – Invasive weeds growing in and beside water bodies have the potential to alter food chains, and their impact on water quality can threaten aquatic ecosystems and fisheries. Water hyacinth which is found in Lake Victoria, Kenya, is a well-known example.

Infrastructure icon

Infrastructure – Invasive species, particularly weeds, can cause significant damage to buildings, drainage systems, railway lines, and other structures. This can add huge costs to development and regeneration schemes.

The impacts of invasive species to livelihoods in the developing world are huge. We have created a dedicated website to highlight the impacts on smallholder farmers in Asia and Africa. With videos and information from our Invasive Species Compendium, it highlights the plight of those affected and some of the worst invasive species.

Controlling the cabbage seedpod weevil in Canada

The cabbage seedpod weevil is a widely distributed pest of cruciferous crops in Europe and North America, causing substantial economic losses in canola crops in Canada. Current control measures still rely on applying broad-spectrum insecticides. We are collecting European distribution data for a parasitic wasp that is the weevil’s most effective... >>

Protecting leeks and onions from pests

The invasive leek moth poses a significant and immediate threat to producers of leeks, onions, garlic and chives in North America. The larvae mine the green tissues, reducing the marketability of crops. The pest’s distribution is expanding, with no signs of suppression by indigenous natural enemies. We are supporting an integrated pest management... >>

Biological control of brown marmorated stink bug

The brown marmorated stink bug is native to parts of East Asia and is invasive in the US, Canada and Switzerland. Here, it is a serious pest of many fruit trees, shrubs and other plants. Chemical control is often used but, with testing, parasitic wasps from China could be used in North America instead. So we want to determine what natural enemies... >>

Africa soil health

Poor soil fertility is a key constraint to improving farm productivity and livelihoods in sub-Saharan Africa. It is now widely recognized that increased fertilizer use, integrated with other soil fertility management practises is the way forward. The Africa Soil Health Consortium (ASHC) brings together experts in soil health, and we bring... >>

Controlling the noxious Russian knapweed in North America

Although native to Asia, Russian knapweed was accidentally introduced to North America over 100 years ago and is now causing untold problems across many states. Some decades ago, a nematode species was used in an effort to control the plant but it proved ineffective. Funded by a US and Canadian consortium CABI has been tasked with researching and... >>

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.... >>