Thrips are a common plant insect pest. They often occur in large numbers, causing damage to buds, flowers, fruit and foliage. There are many different types of thrips, some of which are specific to certain types of plants, while others attack a wide range of ornamental and edible plants. There are also some thrips that are beneficial insects, but these do not cause damage to plants. Many pest thrips also carry viruses that can infect plants causing further damage. The virus is passed on while the thrips feed. For these reasons, it's important for gardeners to know how to control thrips.

Curiously, the name ‘thrips’ always has an ‘s’ whether discussing one or several insects – not ‘thrip’.

 

Seen damage like this in your garden? Looks like you've got thrips. Keep on scrolling for all the advice you need.

 

A guide to identifying and controlling thrips

Here’s our guide to identifying thrips damage on plants and working out how to deal with the problem.

What are thrips?

Thrips are tiny insects – just 1-2mm in length – that cause damage to plant tissue by their feeding. Thrips often occur in large numbers – indeed, one type of thrips is called 'plague thrips' due to the high numbers of insects that infest a plant at a single time. As they are very small, it is often their damage that’s obvious before the pest is noticed.

 

Please tell me how to identify thrips on my plant!

Thrips are tiny insects usually just 1-2mm in length and varying in colour from pale yellow to black. The adults fly and have a pair of wings. The damage is caused by feeding and leads to brown or silver discolouration. Droppings are seen where thrips are actively feeding. Where thrips are feeding on leaf or flower buds, the buds that open or leaves may be distorted.

 

An extreme close-up of a Viburnum tinus leaf with small, black and white insects on it. These insects are thrips.

This viburnum leaf is playing host to a couple of thrips. They're incredibly small and difficult to spot!

 

Which plants are most susceptible to thrips?

All plants are susceptible to thrips, but these insects are most problematic on onions (onion thrips), tomatoes (tomato thrips) and on light-coloured flowers including roses and carnations (often plague thrips).

 

What can I do if I have thrips in my garden?

There are several ways of dealing with thrips. There are beneficial insects such as ladybirds, lacewing larvae, predatory mites and predatory thrips that feed on pest thrips. Commercial growers often rely on beneficial insects to control thrips, especially in greenhouse production. Click here to learn all about the friendly insects that can help save your plants!

Thrips are resistant to most chemicals but can be controlled with some pesticides including pyrethrum and spinetoram (sold as Success Ultra). Always apply pesticides according to the instructions on the label.

Remove infested buds, flowers or leaves, seal them in a bag and put it in the garbage bin. Never put thrips-infested green waste in your compost, as the infestation will spread. Watch new growth closely for signs of reinfestation.

Sometimes thrips infest washing including towels, nappies and underwear and can cause skin irritation when the items are used or worn. To remove thrips in washing, place the affected washing into the dryer.

 

How can I prevent thrips reinfestation?

Thrips are difficult to prevent and have a very rapid life cycle so can recur after initial control. Removing weeds can reduce breeding areas. A healthy garden with lots of beneficial insects can also reduce pests including thrips. Plague thrips are likely to be blown into gardens during hot, windy conditions. Remove infested flowers, buds or leaves when damage is noticed to reduce reinfestation.