Are thrips harmful to the bulb?

They mostly damage the leaves and flowers. However, a weakened plant may struggle to store enough energy for next year.

Can I use water to wash them off?

A strong spray of water can help dislodge them, but you will likely need insecticidal soap to get rid of the population.

What are these bugs on my Giant Onion? Causes and fixes

Check these first

Look closely at the leaves for tiny moving specks.
Check the flower buds for signs of damage or distortion.
Wipe the leaves with a damp cloth to see if the streaks disappear.

Likely causes

Thrips
Most likely
How to tell: You see silvery or white streaks on the leaves and distorted flower buds.
What to do: Spray the foliage with insecticidal soap or neem oil every 7 days. Ensure you cover the undersides of the leaves where these pests hide.
Bulb mites
Rare
How to tell: The plant is stunted and the bulb feels soft or hollow when dug up.
What to do: Remove and destroy the affected bulb to prevent the spread. Do not replant in that same spot for at least 2 years.

Pests on other plants

Find out what's wrong with your giant onion

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

When to worry

Small numbers of thrips are manageable, but heavy infestations can ruin the flower display. If the entire plant looks stunted or deformed, the infestation is severe.

Stopping it coming back

Keep the area around your onions free of weeds that can harbor pests. Maintain healthy soil to keep the plants strong and resistant.

Giant Onion: pests? Check yours with a photo

Every plant is a little different. Take a photo of your giant onion and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

Get the app · Or check it from a photo now, free

Questions people ask

Are thrips harmful to the bulb?: They mostly damage the leaves and flowers. However, a weakened plant may struggle to store enough energy for next year.
Can I use water to wash them off?: A strong spray of water can help dislodge them, but you will likely need insecticidal soap to get rid of the population.

Guides to these causes

Thrips

What are these bugs on my Giant Onion?