10 insect pests that threaten the world's plants

Pests and pathogens are the two greatest threats to plant health. They have killed billions of trees in forest and urban settings worldwide over the last two decades. They also cost global agriculture billions of pounds a year.

Controlling their spread is essential for the environment, economy and plant life. But what pests pose the biggest danger?

Wakehurst’s Surviving or Thriving exhibition, based on Kew’s series of ground-breaking reports on the state of the world’s plants and fungi, has highlighted the bugs that are bad news for plants and where the greatest amount of research into plant health currently lies.

These arthropods not only eat and damage host plants and crops but also help spread various viral, fungal and bacterial pathogens.

The 2017 State of the World’s Plants report ranked the top pests in terms of the number of scientific publications about them in The Centre for Agriculture and Biosciences International (CABI) from the previous five years. Here they are…

Top 10 insect pests to plants

1. Cotton bollworm (Helicoverpa armigera)

Scientific publications: 1,619
Location: Asia, Africa, South America, Europe, Oceania
Top plant hosts: Gossypium (cotton), Cicer arietinum (chickpea)

2. Tobacco whitefly (Bemisia tabaci)

Scientific publications: 1,528
Location: Asia, Africa, N/S America, Europe (few occurrences), Oceania
Top plant hosts: Solanum lycopersicum (tomato), Gossypium (cotton)

3. Two-spotted spider mite (Tetranychus urticae)

Scientific publications: 962
Location: Asia, Africa, N/S America, Europe, Oceania
Top plant hosts: Solanum lycopersicum (tomato), Phaseolus vulgaris (common bean)

4. Diamondback moth (Plutella xylostella)

Scientific publications: 926
Location: Asia, Africa, N/S America, Europe, Oceania
Top plant hosts: Brassica oleracea (cabbage), Brassica

5. Taro caterpillar (Spodoptera litura)

Scientific publications: 853
Location: Asia, Africa, N America, Europe, Oceania
Top plant hosts: Glycine max (soybean), Arachis hypogaea (peanut)

6. Red flour beetle (Tribolium castaneum)

Scientific publications: 829
Location: Asia, Africa, N/S America, Europe, Oceania
Top plant hosts: Triticum (wheat)

7. Green peach aphid (Myzus persicae)

Scientific publications: 811
Location: Asia, Africa, N/S America, Europe, Oceania 95
Top plant hosts: Solanum tuberosum (potato), Capsicum annuum (bell pepper)

8. Fall armyworm (Spodoptera frugiperda)

Scientific publications: 668
Location: Africa, N/S America, Europe (few occurrences)
Top plant hosts: Zea mays (maize), Gossypium (cotton)

9. Cotton aphid (Aphis gossypii)

Scientific publications: 610
Location: Asia, Africa, N/S America, Europe, Oceania
Top plant hosts: Gossypium (cotton)

10. Brown planthopper (Nilaparvata lugens)

Scientific publications: 603
Location: Asia, Oceania
Top plant hosts: Oryza (rice)

Cotton bollworm (Helicoverpa armigera)

First top pest
Two-spotted spider mite (Tetranychus urticae)

Third top pest
Cotton aphid (Aphis gossypii)

Ninth top pest

Why are they so destructive?

The problematic pests in this list are particularly harmful to plant health globally as:

they are widely distributed across countries
feed on a large range of plant species
are resistant to many pesticides
are still spreading

Cotton, Gossypium — Cotton (Gossypium) © Trisha Downing/Unsplash

The causes of spreading

There are many possible reasons for the spread of insect pests, including increased international trade and travel, importation of plants for gardening and planting, resistance to pesticides and untreated wood packaging and climate change.

Insect heroes

As much as these pests are harmful to plants, there are many insects out there having a hugely positive impact.

These helpful creatures pollinate crops, improve soil health and help naturally control insect pests.

How do we stop the spread of pests?

All countries are susceptible to pest plant damage. Halting the spread of pests and pathogens is crucial for natural capital throughout the world.

Here are the ways we can reduce the damage…

International cooperation
Control of regulated or quarantine pests
Prevention of quarantine pests entering a country or area
Eradicating and containing pests
Use of biological control, pesticides and biopesticides

Find out more at Surviving or Thriving: An Exhibition on Plants & Us in Wakehurst’s Millennium Seed Bank Atrium.

Wakehurst

Surviving or Thriving: An exhibition on plants and us

A specially-curated exhibition about the state of the world’s plants and what this means for us.

See the exhibition

A forest landscape has light shining through gaps in the canopy. Leaf litter covers the floor.

Kew Science

State of the World's Plants and Fungi

State of the World's Plants and Fungi provides a cutting-edge horizon scan, taking stock of the world's most valuable and vulnerable plants and fungi.

Read the reports

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