White dots strung along stems and leaf veins, each barely 0.2 mm across, mark where a female thrips has sawn into soft tissue and slipped in a single egg. They hatch in two to seven days, so finding them early decides everything: eggs sunk into the plant must be pruned out, glued ones rubbed off or sprayed with soapy water.
| Size | 1/64th inch (0.2 mm) |
|---|---|
| Per cluster | 2 to 200 |
| Color | white or yellow |
| Location | inside leaves, stems, underside of leaves |
| Hatches in | 2-7 days |
Thrips aren’t always dangerous, but knowing what you’re dealing with helps prepare for the worst. Locating thrips eggs is a first step.
Read also:
Thrips will lay their eggs either inside a plant, or attached to it.
Thrips eggs are lain in soft tissue. Most of the pest species actually lay their eggs inside the plant, in a small wound. These are typically thrips of the Terebrantia sub-order.
This is usually in:
Sometimes this infection triggers galls on the host plant.
Some thrips lay their eggs without wounding the plant.
This special glue that is used is actually a combination of proteins and compounds the thrips produces. It’s very successful in preventing eggs from falling off due to wind and other disturbances!
For those that are inserted inside the plant, only one remedy: prune that part of the plant off!
For eggs attached to leaves or stems, simply rub them with your finger to remove them. You can also spray a mix of soap and water to suffocate the eggs.
For most thrips, a special pointed organ called an ovipositor is located at the end of the female thrips’ abdomen. This is used to slice through outer plant tissues.
The thrips then inserts a single egg in this wound.
The eggs are quite large compared to the adult. Each egg is often about one-fifth of the length of the adult thrips body.
Thrips of the Tubulifera order don’t have this ovipositor. Instead, they’ve developed powerful glues that seal their eggs in place.
Normally, for most insects, unfertilized eggs result in male hatchlings, whereas a fertilized egg produces a female specimen.
However, many thrips species are able to reproduce even when no males are present. This is called complete parthenogenesis. In this case, an unfertilized egg produces a female specimen. Usually this is the result of an infection by a particular bacteria that interferes with the reproductive system.
Where a female thrips puts her eggs decides both how you spot them and what you can do about them. The table below sums up the three placements described above.
| Where the eggs are | Thrips group | How to spot them | How to remove them |
|---|---|---|---|
| Inserted inside the plant, in a small wound | Terebrantia | White dots along stems or leaf veins, one or several eggs per dot | Prune that part of the plant off |
| Glued to the underside of leaves | Tubulifera | Visible clusters on the leaf underside; a magnifying glass helps | Rub them off with your finger, or spray soap and water |
| Wedged into bark crevasses and leaf joints | Tubulifera | Hidden in tight crevices where stems and leaves meet | Rub them off, or spray a mix of soap and water |
Eggs sealed inside plant tissue can only be cut out, whereas glued eggs are within reach of a finger or a soapy spray.
Within two to seven days, the eggs hatch under the surface. For thrips, the hatchling is quite similar to the final adult, but smaller in size and often lacking wings. It chews its way to the surface and starts crawling around to find a place to feed.
For thrips, the word “nymph” is more correct than the word “larva”.
As soon as they hatch, the thrips nymph is already equipped with mouthpieces to feed.
It even has a rather successful way of defending itself against predators! It curves its abdomen back upwards, and then releases the strain in a powerful flick! This helps it fight off many pest-eating insects like other beneficial thrips, ladybugs, and more!
