Thrips are nasty insects. They’re very small and thin. They can fly, but fortunately not very well and not far. Like Spider Mites, they want the chlorophyll from your cannabis plant leaves. They scrape the surface and can cause quite a bit of damage.
There are many species of Thrips. The main ones you’re likely to encounter are Greenhouse Thrips, Western Flower Thrips and Onion Thrips. There are also Oxythrips, which are dedicated cannabis feeders. While some growers have reported problems with Oxythrips, they’re quite rare, especially compared to the other species mentioned.
NATURAL ENEMIES OF THE THRIP
Amblyseius cucumeris is a predatory mite which attacks the first and second instar larvae of Thrips. Amblyseius cucumeris is a clever no-nonsense Thrip killer which senses Thrips emerging from the cannabis leaves. It waits patiently for the little Thrip heads to pop out and then unceremoniously, chomps those heads right off.
Stratiolaelaps scimitus (Hypoaspis miles)
Our old friend Stratiolaelaps scimitus, which should already be in the soil, will make sure that the cycling of Thrips is reduced, possibly by up to 80%.
Rove Beetles (Dalotia coriaria or Atheta coriaria)
Another old friend, the Rove Beetle, will also eat Thrips while they’re in the soil. Make sure you’ve got 1 Rove Beetle for every 10 square feet of greenhouse.
Nemasys can also help with Thrips. The Beneficial Nematodes of Nemasys can help manage many pests. It’s a product mentioned under Fungus Gnats. Have a look.
OTHER METHODS OF THRIP CONTROL
From the get-go you should have a 1 yellow sticky trap for every 500 square feet of greenhouse. Don’t place these traps higher than the plants, or the Thrips will head to the plants rather than the traps.
For Thrips, you can increase the allure of the trap ten-fold by adding a few drops of either almond or vanilla essence to a cotton ball and sticking it to the trap.
We offer lures which work in the same way.
Bush Beans (Strike and Provider varieties)
Thrips like beans, which are more attractive targets for them than cannabis. Bush Beans also allow you detect Thrips early on in the game. Grow the beans from seed and place the plants as close to, even touching, the cannabis plant. Thrips might be tempted to hop across.
A tub of soapy water might be just the thing to clean your greenhouse of Thrips. Use this to wipe out large numbers of Thrips. Make sure the tub is yellow or white, about 18 by 12 inches, and 6 inches deep. Fill the tub with water and add a little dish washing liquid, stir it up. Again, you can add some vanilla or almond essence. Adult Thrips should be drawn to the tub, its scent. The scent will last about three days. If you see that it’s working, then repeat until the Thrips are all done for.