Western flower thrips, also interested in veggies!

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Silver-white patches spread across the leaves, turning yellow-brown, black specks litter both sides, and white spots freckle coloured petals: these are the marks of Western flower thrips (Frankliniella occidentalis), best known for carrying the fatal tomato spotted wilt virus. Keep it off tomatoes and their relatives and the damage stays mostly cosmetic, with the plant itself usually surviving.

veggies.

This tiny pale-yellow thrips might contaminate your tomato plants with the fatal tomato spotted wilt virus. But for other plants, damage is mostly cosmetic.

Damage caused by Western Flower thrips

Key symptoms most certainly reveal an infestation of Western flower thrips.

Tomato Spotted Wilt Virus

A devastating disease is transmitted by Western Flower thrips as it feeds from one plant to the next.

A thrips that has fed on an infected plant at any stage of its lifecycle will infect all other plants it may feed on.

Many plants of the Solanaceae family can catch the disease if a contaminated thrips lands and feeds on them: tomato, potato, eggplant…

• Other families can also catch the disease: Capsicum (chili and bell pepper plants) and lettuce will also suffer from this viral plant illness.

Symptoms of Western Flower thrips on plants

A colony of Western Flower thrips will result in cosmetic damage mostly. In some cases like vegetables or fruits, however, the harvest may be reduced in quality and quantity, too. The damage is similar to that of other thrips.

• What does thrips damage look like?

A few telltale signs are the following:

• silver-white patches on leaves, these turn yellow-brown after while
• black specks littered on the under and oversides of leaves.
• As the white patches spread, leaves may start twisting and scarring.
• On colored flowers, you’ll notice white spots on petals.
• Of course, you might glimpse the tiny insects themselves.

As a result, ornamental flowers aren’t as beautiful. Fruits and vegetables are smaller and the harvest is less abundant, and they may even be scarred and unsalable.

• It’s still safe to eat the harvest: thrips don’t cause toxins or poisons. At worst, the taste will be a little “off”.

Thrips will rarely kill a plant.

Telltale signs, and what each one means

Western flower thrips leave a handful of very recognisable marks. Use the signs below to work out where to look and how far the infestation has gone.

None of these signs is usually fatal in itself, since thrips will rarely kill a plant.

Western flower thrips host plants

Western flower thrips have been found feeding and/or reproducing on over 250 different plants belonging to many different families.

Nearly all ornamental plants will at some point carry these thrips:

• Chrysanthemum,
• gerbera,
• roses,
• a few orchids like Phalaenopsis
• and gladiolus

are among the most vulnerable.

• Because western flower thrips (Frankliniella occidentalis) transmit tomato spotted wilt virus and move readily between hosts, avoid planting susceptible ornamentals such as chrysanthemum and gerbera beside tomatoes, peppers or lettuce, where they can serve as virus reservoirs.
• Flowering weeds such as chickweed, dandelion and sowthistle also host Western flower thrips, so clearing them from around the plot and greenhouse removes a hidden reservoir before susceptible crops go in.
• Western flower thrips hide deep inside buds and open blooms, so check host plants by tapping a flower over a sheet of white paper and watching for pale specks that crawl away.
• Inspect the flowers of newly bought gerbera, chrysanthemum or Phalaenopsis before bringing them home, and keep them apart from tomato and pepper seedlings until you are sure they carry no thrips.