Thrips

[MateoinLosAngeles]

Hi everyone,

Dealing with summer pests over here and this year we got a new one... thrips!

Thrips is a pest I've been able to avoid... until now. I've dealt with spider mites, aphids, fungus gnats. Since all my pests are soft bodied I usually use insecticidal soap and rotate it with organishield. For spider mites I might use Azamax and for fungus gnats I either sprinkle mosquito bits or use solutions containing Bacillus thuringiensis products.

I was a happy and naive orchid grower, with the head in the clouds, feeling invincible until I saw it... a slender insect resting on the petals of a newly opened white Phalaenopsis, one of those with big flowers. "This is not a fungus gnat," I thought, and there I had it, the first 'visible' thrip, finally paying that long-dreaded visit and making me face my destiny...

When moving plants to be treated I notice two things: they fly, and they dislodge pretty easily (I would think they're drunk). Spinosad-based soil drenches seem to be useless on flowers and I'm not especially excited about spraying flowers, even with water, and cause who knows what kind of unsightly damage. I also grow indoors, so even though the "big guns" can be used for some plants (esp if I treat outside). I would prefer to work inside.

Does anyone have suggestions on:

1. Using Beauveria bassiana products against thrips.
2. Spraying on flowers, would alcohol perhaps work without causing flower damage?
3. For growing area control and to manage flying thrips, has anyone tried Pyrethrin products? A product like Stryker 54 aerosol is labeled for residential use as a "space spray" some other synthetic pyrethrin products are labeled as "residuals" for flies. But none are labeled to be used direct on plants and they could leave residue on the leaves, not to mention on the flowers.
4. Has anyone tried a spinosad product or concentrate that sprayed on flowers left them relatively unharmed?

Just a reminder that I'm looking for products labeled to use indoors! Unless absolutely necessary to bring plants outside

[jiblylegs]

When we I’ve had thrips with plants, I use imidacloprid. It’s a systemic insecticide that you water in. It’s always done the job for me with about two applications. I wouldn’t use this on any plant outdoors as it causes colony collapse disorder. It is banned in the EU.

[plantxart]

thrips are the worst. they lay eggs inside the plant tissue. I've tried introducing biological control and other less harsh methods. Any spray on products will only kill the adults. The most effective by far is using a systemic insecticide such as imidacloprid. I know its very toxic so handle carefully

[estación seca]

For Vandas, Motes has suggested spraying just flower spikes weekly with a household aerosol insect killer, beginning soon after they are visible.

[Clawhammer]

Took me a year and a half to eradicate my infestation. I finally got rid of them by alternating Conserve (only spinosad that works) and pyrethrins every 3-4 days for 8 treatments.

[MateoinLosAngeles]

Originally Posted by Clawhammer

Took me a year and a half to eradicate my infestation. I finally got rid of them by alternating Conserve (only spinosad that works) and pyrethrins every 3-4 days for 8 treatments.

How do you apply the pyrethrins?

[Clawhammer]

Originally Posted by MateoinLosAngeles

How do you apply the pyrethrins?

Spray everything, especially the flowers and buds. Thrips also munch on catasetinae leaves and other similar deciduous like leaves, so concentrate there too.

[MateoinLosAngeles]

Originally Posted by Clawhammer

Spray everything, especially the flowers and buds. Thrips also munch on catasetinae leaves and other similar deciduous like leaves, so concentrate there too.

I’m pretty sure that a recent leaf drop I had on catasetinae was due to Thrips. I treated with Organishield and Azamax because I thought “it must be spider mites” and spider mites can actually thrive on Imidacloprid, for whatever reason. But I haven’t seen anything upon inspection except for adult Thrips. I think it’s a mild or a recent infestation because I don’t see larvae anywhere and I’ve only seen about 2-4 adults, but I know they’re sneaky. I will treat the Catasetinae with Imidacloprid as I think that’s where they’ve been more active and nested, and probably spray them and everything else with pyrethrin. Then watch.

[estación seca]

Imidacloprid kills arthropods by contact or by ingestion. Organisms that eat leaves or suck juices from plant vascular tissue will be killed. It does not enter plant cells. If you spray it on spider mite bodies it will kill them. However, most preparations are soil drenches. Spider mites suck juices out of individual plant cells, not out of the vascular tissue, so they are not exposed to systemic imidacloprid. Also, spider mite webbing is a barrier to contact pesticides. A wetting agent is necessary.

Thrips are outside in the landscape in metro Los Angeles. They lay eggs in leaf litter, often far from plants. This is one reason for keeping a very clean growing area. I haven't read of them laying eggs in nor on plants. There are citrus thrips in metro Phoenix but members of our society haven't seen them on our orchids.

[MateoinLosAngeles]

Originally Posted by estación seca

Thrips are outside in the landscape in metro Los Angeles. They lay eggs in leaf litter, often far from plants. This is one reason for keeping a very clean growing area. I haven't read of them laying eggs in nor on plants.

Do you have suggestions/speculation about how an infestation could get indoors? We only have plants, and the growing area is kept clean. I initially thought they could've come with some fresh herbs we bought and potted (although far from the orchids).

We stopped bringing flowers home, but sometimes people bring them for dinners, etc. We throw them away afterward, but maybe they stayed in the trash for too long (never longer than two days, but, alas).