This post is part 3/3 of the thrip management series. Today we will be discussing what treatment options you have once thrips are spotted.
Step 1: ID the species. See Managing Thrips Part 1: How to ID thrips species
Step 2: Choose the most effective control option available against that thrips species
Understand what options you have
Analyze the cost vs benefit when using any control method. Ask yourself, can the plants manage with the preventative plan already in place? If not, what is the level of infestation? If there are only a few hotspots in the greenhouse, could you manage by releasing additional thrip predators in the hotspots. OriLiv (orius insidiosus) is usually the most effective for managing thrips since it can attack all mobile life stages. Additionally, releasing SwiLiv (Ambluseius swirskii) or Cuculiv (Neoseiulus cucumeris) can also help reduce the juvenile stages of thrips.
If there are many hotspots throughout the crop, then natural enemies alone will not be able to keep up with thrips. Thrips can breed very fast especially when ambient temperature is warm (25-28C). In this case, a chemical intervention may be necessary to knock down the population before adding the natural enemies.
Are you able to use insecticides without disrupting the biocontrol agents?
Biocontrol agents are usually very sensitive to most chemicals whereas thrips have been frequently sprayed, resulting in highly resistant population in most cases.
How to minimize damage?
- Use spot treatment of chemicals that are least harmful to the biological agents.
- Drenching of certain chemicals may have the least toxicity to true carnivore predators, such as predatory mites. However, it may cause adverse effects to certain parasitoids (Aphidius colemani) or omnivorous predators (Orius insidiosus).
- Spraying only a part of plant (lower or top) keeping in view the high activity area of certain target pest as well as the beneficial to save.
- Consult GrowLiv advisor for guidance.
Other tips to decrease thrips
If there is a heavy population of juvenile stages of thrips, remove the infected plant material. Make sure to dispose of it properly away from the greenhouse.
Lastly, increase the use of mass trapping such as yellow/blue sticky traps to get the flying adults. Removing even a few adults can result in lowering the population over time. Sticky traps should remain 6-9” above the crop canopy for the best results.
We hope this 3-part series was educational. Let us know in the comments below what other topics you'd like us to cover 🐞