Thrips species exist by the thousands, but they can all be sorted out into three major types of thrips: pest thrips, predatory thrips, and recycler thrips.
Knowing which type of thrips is on your plant will help you take action to either protect or treat it.
Thrips are tiny insects. Most thrips species are pests or parasites: they feed on plants and even use plants to hatch their offspring in.
- Usually these insects are the size of a dot at the end of this sentence.
- They’re often noticed when silver white spots appear on leaves.
- Feeding damage results from thrips stabbing through the surface of a leaf or fruit and sucking up sap as it wells out.
In the garden, they’re rarely problematic. Indeed, a host of other beneficial insects is available to control thrips naturally.
However, in agriculture and horticulture, thrips can wreck havoc and completely destroy a harvest if left untreated.
- Almost all the most common parasite-type thrips are from the Terebrantia thrips species.
Most common pest thrips
Thrips in the garden
- The only time you’ll truly regret encountering pest thrips is when you’re growing tomato.
- Different thrips feed on tomato plants. After feeding on a contaminated plant, adult thrips will spread a lethal viral disease from plant to plant.
- This disease, called the tomato spotted wilt virus, causes leaves and tomatoes to grow deformed and die off.
Crop-damaging thrips in agriculture and horticulture
Farmers and greenhouse managers have more to worry about when it comes to thrips.
- For horticulture and ornamental flowers, thrips can disfigure flowers, blooms and leafage. Plants and seedlings become impossible to sell.
- Fruit and vegetable growers have similar problems: fruits will be streaked and marked. Customers won’t find them attractive, even though they’re perfectly safe to eat once the skin is removed.
Thrips eating thrips
Some thrips aren’t plant-feeding: they eat other insects instead. After hatching, enemies will be eaten during the entire lifecycle of the thrips.
Many predator thrips eat eggs, nymphs and larva from other thrips that are usually pests, and even the occasional adult, too.
- They’re so good at it that half the thrips species evolved to lay their eggs inside plants instead of atop or under them!
Predatory thrips will also eat other insects, too. This includes:
It’s a great help to have these predator thrips in the garden! They’ll help you control many tiny pests that might otherwise damage your flowers, fruits and vegetables.
- Predatory thrips are among the best beneficial insects, up there with the green lacewing and the beloved ladybug.
Most common predatory thrips
- Delivered in a sachet or pouch.
- Quantities depend on the severity of the pest invasion.
- Predator thrips are often sold as adults. Sometimes they’re sold in the larval stage (nymphs).
Thrips, experts at managing waste
A very large portion of thrips are completely innocuous to both plants and other insects. These specialize in feeding on decaying plant matter or on fungus.
- These species of thrips are often found in decaying wood, under old bark, in the first few inches (3-5 cm) of soil, and around old wounds on trees.
They play a crucial role in the breakdown of dead organic matter. Together with fungus, thrips are among the many insects that can be seen squirming and wriggling in rich soil.
- Breaking down matter – Plant matter is broken up by the feeding into smaller bits.
- Digestion – What is eaten is digested and released in the form of tiny droplets of nutrient-rich fecal matter.
- Soil structure – As they tunnel through the ground and layer of humus, thrips open up pathways for roots to weave into.
- Drainage and air circulation – The same tiny tunnels help air and water flow even into clumps of dense clay.
Some types of thrips feed specifically on fungus material. These help control certain fungal diseases. Fungus spores are sometimes just the right size for a thrips to feast on!
- The Allothrips species is a typical example of fungus-eating thrips. It is very common in many parts of the world (North & South America, Europe, Asia, India, South Africa, Australia, Middle East…).
- It feeds on fungus spores from mushrooms that dissolve dead leaves.
- The largest type of thrips, Idolothrips spectrum, is also a fungus-spore-feeder. It’s the world’s largest thrips at over half an inch in size (1.5 cm)! The common name for this thrips is “Giant thrips” – well-earned, no?
In other cases, the fungus itself is the food. Thrips will nibble at the fungus mycelium as a source of food.
- This explains why it’s important to sterilize the growing medium when growing mushrooms.
- If not, you’ll be importing such fungus-eating thrips. They will eat and weaken your mushroom production!
- Learn to grow mushrooms on old coffee grounds
Thrips and pollen
Many types of thrips also feed on pollen. This isn’t usually a problem for the flower. Quite the opposite!
- Pollen-feeding thrips are often very helpful because they pollinate the flowers they feed on.
- Just like bees, thrips wander from flower to flower in search for food.
- Pollen clings to their back and on other body parts, and is deposited on other flowers.
- Some pollen is lots to the thrips feeding, but enough remains and is transferred so that each flower is pollinated.
Additionally, some predatory thrips are also able to feed on pollen. This helps them survive in case other pests and prey have been driven out.
Smart tip about different types of thrips
Thrips are marvelous tiny creatures. Take your magnifying glass when gardening with children to spark wonder at the miniature world at their feet!
Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Tubulifera thrips on leaf by Katja Schulz under © CC BY 2.0
Banana pest thrips by Chris Mallory under © CC BY-NC 4.0
Wasp-like thrips larva by Jesse Rorabaugh under Public Domain
Thrips on old wood by Katja Schulz under © CC BY 2.0
Giant thrips by Karl Magnacca under © CC BY-NC-SA 4.0