How to Get Rid of Thrips

If your plants are growing vigorously, and then they seem to decline and die for no apparent reason, you could be dealing with an infestation of thrips. These pests are especially prevalent in the greenhouse, where they enter through vents and flourish in the hothouse environment. You can control thrips before they deform your plants and infect them with the diseases they carry.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• Nematodes
• Ladybugs
• Insect soap
• Insect growth regulator
• Sticky traps

1. Use beneficial nematodes (see resources below) that dwell in the soil and feed on thrips and other pests. You apply these nematodes in the early spring, when thrips are in the pupa stage.

2. Release ladybugs into your garden or infested greenhouse. If you release your ladybugs outdoors, do so in the evening when winds are calm to prevent your predators from flying away.

3. Keep your greenhouse fallow for one season. The best time to do this is summer, when you can move all tender plants outdoors and allow greenhouse temperatures to soar to levels lethal to thrips.

4. Spray plants affected with thrips with insect soap. Use insect soap when temperatures are below 80 degrees F, as high temperatures increase the chance that this pesticide will burn your flowers or foliage.

5. Select an insect growth regulator formulated for thrips. These products arrest the development of juvenile thrips, so they can't produce the next generation of pests.

6. Maintain excellent greenhouse hygiene standards. Pull all weeds around your greenhouse, and quarantine new plants before you introduce them to your existing garden.

Tips & Warnings

• Set out sticky traps to help you identify a thrips infestation. You can attract the most pests with yellow or bright blue cards.

Resources

• Buy beneficial insects.
• Shop for insect growth regulators.