An excellent natural adaptation capacity? That’s why thrips have become one of the most feared and widespread pests. The most common and harmful species are the onion thrips Thrips tabaci and the western flower thrips Frankliniella occidentalis. These pests are less sensitive to pesticides and cause serious damage to vegetable crops as well as to ornamentals and soft fruit. Only a few individual thrips are enough to cause severe damage. Fortunately, biological control can help you out!
What damage can thrips cause?
- Thrips cause severe damage by sucking plant cell fluids.
- The empty cells are filled with air, which makes them look silvery with dark spots (excrements).
- Different damage symptoms can occur depending on the crop e.g. thrips on young cucumber plants give deformed fruits.
- Thrips spread several viruses such as TSWV.
How to control thrips?
To monitor the thrips, you can rely on Biobest’s Bug-Scan® in combination with the species-specific aggregation pheromone ThriPher.
For biological control of this species, you can introduce:
To boost the population establishment of your beneficials, you can use the feed supplement Nutrimite™ in addition to Swirskii-System and Degenerans-System.
What are the characteristics of thrips?
- The adults of about 1 to 1.5 mm are elongated, greyish to yellow-brown with typical fringed wings.
- On most crops, eggs cannot be spotted as the eggs are in the tissue of leaves, petals and stalks.
- Young larvae of 0.5 mm are almost transparent-white or yellowish to orange-yellow.
- Larvae of the second stage are about 1 mm long.
- Prepupal and pupal stages can be found in the upper layer of the soil but also on leaves, flowers and other shelter spots.
- You can recognize prepupa and pupa by their wing buds.
What about thrips’ life cycle?
- Thrips have 6 development stages: egg, 2 larval stages, prepupa, pupa and adult.
- Female thrips lay up to 200 eggs when temperatures are high.
- The eggs hatch within a few days and become mobile larvae that immediately start to feed.
- After the second instar, larvae let themselves fall onto the ground to pupate.
- It takes them about 20 days to develop from egg to adult at 20 °C/68 °F and 10 days at 30 °C/86 °F. Above 35°C/95°F and below 10°C/50°F the development stops.
- Thrips develop better on pollen-bearing plants such as sweet pepper than plants without flowers.