Managing Thrips

[Shadeflower]

Keith,
many do believe the secret is just watering and being patient

But I like what you wrote, couldn't have said it better

Ps: the biggest threat to me losing patience is Thrips.

Here is a half hour video to share my frustration (no not me, another growers from canada)

and realize that dealing with thrips takes so much more patience than watching a 36 minute youtube video talking about them.

Thrips!! Get Rid Of Them For Good!! (101 Wednesday's) - YouTube

[K-Sci]

Originally Posted by Shadeflower

Here is a half hour video to share my frustration (no not me, another growers from canada)

It's off topic, but since she doesn’t get to the title subject until 19 minutes in, here’s a synopsis:
Precautions: Repot /wash/ treat incoming plants, vegetables, fruits, flowers, etc. prior to bringing them into the growing area.
Indications: Thrips are very small/hard to see and eat just about any plant and any part of a plant. Find them with a flashlight and magnifying glass. The damage they case is elongated spots that turn silvery then brownish on leaves, flowers. They may also cause misshapen leaves or flowers.
Treatment: She prefers "natural" solutions.
1) Isolate the plant from other plants and anything used in growing. Wash hands/arms after handling.
2) Thoroughly check surrounding plants with a flashlight and magnifiers. 5) Treat immediately.Rinse/spray tepid water on entire plant outside or in a tub to remove exposed thrips/eggs. A lint roller may also be used.
3) Once per week for a month spray all plant surfaces with 1 tsp/liter insecticidal soap (unspecified type – but not horticultural oil).
4) Combined treatment approaches are more effective.
Prevention: See also precautions, above.
1) Neem oil is only good as a preventative b/c it is not a contact insecticide and must be eaten.
2) Use blue sticky traps for thrips (Amazon.com). [ed. The traps can also be used to determine if a variety of pests are present.]
3) Inspect often.
4) Use beneficial insects such as predatory mites (eat the eggs) or Lady Bugs/Green Lacewings (eat the thrips). She has used two rounds of predatory mites (Koppert Swirski Ulti-mite) but still found thrips afterword. Predatory insects will be killed for about 2 weeks after insecticide/miticide application. [ed. when I used Lady Bugs, a couple plants previously treated for ants many weeks earlier ended up surrounded by dead Lady Bugs].

-Keith (note - I've never had thrips, so can't vouch for the above)

[Shadeflower]

Sorry to share my frustration, but you are better prepared for it now.
One thing to take from that video is once things have spread badly it comes down to a numbers game.

If like her you have 300 orchids you might think, ok treat them all, treat them again a couple weeks later and you're done.

But it doesn't work out like that in reality. What really happens is you treat a few, then you treat a few more a few days later.

Lets say you give each orchid 3 treatments, well for a collection of 300 that is on average 3 orchids per day for an entire year.
And in that time they just keep jumping around and reinfection other plants again.

Sorry to take it off topic, I suppose I really did. Like ES I believe getting rid of the thrips will do so much more good than any vodka at mine at the moment can but no reason to dismiss anything that is beneficial of course.

[WaterWitchin]

Originally Posted by Shadeflower

One thing to take from that video is once things [thrips] have spread badly it comes down to a numbers game.

If like her you have 300 orchids you might think, ok treat them all, treat them again a couple weeks later and you're done.

But it doesn't work out like that in reality. What really happens is you treat a few, then you treat a few more a few days later.

Lets say you give each orchid 3 treatments, well for a collection of 300 that is on average 3 orchids per day for an entire year.
And in that time they just keep jumping around and reinfection other plants again.

I noticed that she said to use multiple methods, but didn't recommend multiple (compatible) treatments. I don't like treating plants with insecticides, but when I must I usually use a hand-pump spray bottle of Seven. Even still if I use Lady Bugs I'll find dead ones around the treated plant during a release many weeks later.

I no longer use insecticidal soaps or Neem oil because I've found them to be ineffective on scale, aphids, and mealy bugs. I see no reason why building up an immunity would be limited to synthetic insecticides. Building up a resistance to being eaten by a Lady Bug is pretty much impossible.

Have you tried using pyrethrum foggers? Maybe foggers are not an option in your situation.

It also seemed the woman in the video is talking about terrestrial plants (many in the background). I assume orchids would be harder because pests can get into the media. Honestly, based on reports, I'd rather have just about any other pest than Thrips

Sorry to take it off topic, I suppose I really did. Like ES I believe getting rid of the thrips will do so much more good than any vodka at mine at the moment can but no reason to dismiss anything that is beneficial of course.

It is a good topic and I don't mind going off topic in the least, but I think some people do. It would be nice if the mods moved our post on this topic to a different subject, say "Managing Thrips" under "Advanced".

-Keith

[Shadeflower]

I went round the garden tonight with a torch, blew on every pot, checked for movement, spotted one predatory mite (I presume) but not a single thrip.

Strangely enough those predatory mites have spread far and wide too by now. I do not really like them that much because although they do keep numbers in check they never eliminate the problem completely, ie they leave just enough to keep themselves fed. But if something happens like the weather getting more favorable for thrips then they can multiply fast and just hop elsewhere where the predatory mites can't follow.

Ps I never bought any predator mites but they have slowly been reproducing. I'm just glad they are not a threat because they seem to be even more resilient than thrips!

my collection of different thrip pictures:

[K-Sci]

Shade, have you tried using pyrethrum foggers? Maybe foggers are not an option in your situation.
-Keith

[Shadeflower]

yeah not really an option. I've had them in the cupboard for a while, got too many pets.

Like said not a single one spotted.

I repotted a phal tonight, inspected it, thrip free

I know I haven't eradicated them completely but I've made good progress.

The pot gets soaked in soapy water for 5 minutes drowning all the adults - thats how I was able to take those pictures and for scale, those air bubbles are the size of sand.

The leaves all get sprayed with a 2 week systemic insecticide during the soak and back they go.

[jldriessnack]

Honestly, the product Endall has always worked for me. It uses a combo of pyrethrins, salts, and neem. I have used it to get rid of tx resistant scale and thrips and it is very effective. You do need to be careful with it though - especially if you have cats that chew leaves.

Luckily, the halflife of pyrethrins is pretty brief. In sunlight and in water it is just a matter of days.

[Clawhammer]

I have 450 orchids in a basement and had thrips for 1.5 years. I eliminated them this month but had to go all in:

1.) Defoliated catasetinae as thrips can survive on the leaves.
2.) Removed all in bloom flowers and advanced buds.
3.) Treated the whole collection every three days for 10 treatments, alternating spinosad and pyrethrin.
4.) Drenched each pot with imidacloprid

Thrips are hard to defeat once they have infested the grow room. A few tips:
1.) Thrip damage is always clear/gray patches starting at the edges of the flowers. They suck all the juice and leave cellophane like cell walls behind. If the patches are brown, its not thrips.
2.) Thrips can easily travel between plants that touch and on human hands and noses. They have a difficult time moving between pots if plants are not touching or they don't have a vector.
3.) They are asexual an 1 female thrip can reproduce by herself.
4.) They are brilliant at hiding and will flee for cover when the sense your presence.
5.) They lay eggs in flower buds which become little incubators and ultimately blast.
6.) They have 5 stages of life and are only visible to the naked eye in the final stage. They spend 2 stages in the soil.
7.) They seem to prefer catasetum and cattleya
8.) They are little bastards (see point 3)

[K-Sci]

Originally Posted by Clawhammer

... Drenched each pot with imidacloprid

I didn't know imidacloprid was safe as a drench. It's a systemic, so I suppose that's a good way to get it throughout the plant.

Something just as valuable as what worked, is what you tried that didn't work. Do you mind telling some stories?

-Keith

---------- Post added at 12:19 PM ---------- Previous post was at 12:14 PM ----------

Originally Posted by Shadeflower

yeah not really an option. I've had them in the cupboard for a while, got too many pets.

Like said not a single one spotted.

I repotted a phal tonight, inspected it, thrip free

I would love to hear that you finally defeated the little bastards (see clawhammer point 3). What a nightmare.


-Keith

---------- Post added at 12:24 PM ---------- Previous post was at 12:19 PM ----------

Originally Posted by Shadeflower

Sorry to share my frustration, but you are better prepared for it now.

Somewhat ironically, the thrip frustrations you and claw shared seemed to leak into the atmosphere and affect me at a distance. After reading your posts bought another 1500 ladybugs that I released in my greenhouse today - just out of sympathy.



-Keith