Know your enemy (Thrip)

I’m back again with another entry in the Know your enemy series, this time I’d like to talk about Franklinellia Occidentalis, or the Western Flower Thrip.

This particular pest is more economically damaging for people that grow ornamental flowers, but in the cannabis space they can be a real nuisance due to their fast ability to spread and the potential difficulty in controlling their reproductive cycle. Furthermore, they generate a surprisingly large amount of excrement that they will leave everywhere they go, which could potentially vector bacteria and contaminate your flowers in the event of a large infestation.

Biology:
Thrips have a six stage life cycle: Egg , two larval stages , prepupal, pupal, and Adult. Larvae and adults are found in the foliage and are the stages that are damaging to the plant, however in order to pupate they drop down and burrow into the soil. This adds an additional dimension to your control plan, because if you don’t do anything to treat the soil you’re a lot less likely to be able to get a firm grip on a problem.

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The first signs you’ll find of an infestation are silverfish-gray scratches on your foliage, their feeding method is termed “rasping” and they leave very distinct scars on your leaves, as well as clusters of black specks which mark their excretion sites.

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Controlling thrips should come along nicely with your overall IPM program for your grow. Most chemicals that you would be using regardless are also effective against thrip and many beneficial insects will also control thrip in addition to others. The main predators of thrip that I make use of are:

Amblyseius Cucumeris – This mite is an excellent predator of early stage thrips. Specifically eggs and the first larval stage. Its not large enough to consume the second larval stage and adults, however it is an integral part of the control plan for its ability to manage the beginning of their reproductive cycle. Available in slow release sachets for preventative dispersion

Orius Insidiosus – One of my personal favorite predators, they are excellent at controlling all life stages of thrip and they are capable of flight and thus are highly mobile. Its also quite easy to establish and maintain a banker system for these insects so if anyone is curious about that just drop me a comment or a DM and I can walk you through it. Release throughout the grow, they spread quickly although they are hard to spot again once dispersed.

Dalotia Coriaria – Also known as “Rove Beetles” these are my favorite soil dwelling predator and will be terrific at managing the pupal stage of thrip in the soil. I have also worked out an effective way to breed these insects as well that I would be happy to share if anyone is interested. Its a lot of work and I have since stopped, but over 1.5 years after stopping the breeding program im still finding them in the greenhouse so they seem to have become firmly established.

Hypoaspis Miles – Everyone’s favorite soil mite, also excellent at controlling soil pests. Not as flashy as the Rove beetles, but that’s not their fault.

Chemical Controls:
Really any biological insecticide should be effective as canopy treatments vs. Thrip. Azadirachtin, Grandevo, Botaniguard, etc all good. For treating the soil, I usually drench with Molt-X and beneficial nematodes. Both of which are pretty compatible with soil predators (For all intents and purposes just meaning <25% pop kill so take that for what it is)

Lets get a discussion going, how do thrip impact you guys?

Additional image of adult thrip caught in the act:

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Luckily these suckers are easy enough to keep at bay. I would say they’re in every bag of promix out there!

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Love reading these. Keep them coming!

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I appreciate this series, @Gregory

There’s huge potential here. I wonder when @Future is going to spin off a F4200 cultivation site. Maybe even crypto #Futurecoin perhaps? :joy:

EDIT: I know he’s got his first Level 3 slanger if he does!

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If he does I want @Gregory to be apart of it!

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Absolutely, out of all the pests you could end up getting Thrip are the most likely but also among the least damaging thankfully. However since all it really takes is a hot bag of soil or some missed weeds growing up in the rows to set off an infestation its important to keep them in mind and plan for them.

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I agree. I let them get outta control once and they got everywhere! Had to take apart damn air handler! lol

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Man im only bummed it took me so long to catch wind of this site, I love this shit and even if Future4200 isnt specifically cultivation focused there are alot of talented growers to learn from here anyway and they’re out here dishing out the knowledge, its an inspiration.

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The nice thing about this site is we have true players in the mix. It’s nice to get trustworthy advise from the pros!

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Thanks for the knowledge drop and starting the new threads. I grow hydro but finished some plants for someone and they were in dirt. They def did not have thrips when I got them but I bought soil and repotted and I am positive thrips where in the soil mix. I used Orius Insidiosus(Minute Pirate Bug)and after 1 treatment they were gone. I also am back to hydro(DWC)so no dirt for them to pupate in so I am sure that helped.
I cant see me ever going back to soil again.

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I am such a big fan of the Orius I love to hear when other people have success with them. Definitely the soil mix was probably your vector there; even when stuff is advertised as ‘heat treated’ you’ll still find pests in it a considerable amount of the time. Just the hangtime of having them stored in a warehouse for X amount of time is often enough for pests to decide it will make a good home. I’m personally a big fan of growing in soil, despite the obvious benefits of going hydro. I like the simplicity, and frankly soil / soilless media is very forgiving of mistakes compared to hydroponic. Personally I use the dehydrated coco coir; its about as dirt cheap and basic bitch as you can get as far as soil is concerned.

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Great posts man. Love the community of knowledge sharing here.

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Thanks dude, I’m just glad people are enjoying it I love to start up discussions like this, maybe I just like to talk haha

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The easiest way to control thrips are first In the early veg stage, we use the Monterey brand garden spray with Spinosad. Every other day for a cycle of about three treatments
Usually wipes them out within a couple days

I do appreciate the predator tech though. So thanks buddy

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I second the spinosad.

I have had them on various crops. Drugstore peroxide diluted 50 50 with water will kill the black mold that grows on their poop, same with whitefly residue.

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Is this one of thise buggers? He kept looking at me while i scoped him. :eyes:

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I’ve used doktor doom and pyrythrin tr for aphids/thrips and those foggers work great :+1:

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Dr doom is watered down big time. It is 2.4% active ingredients and the BASF brand is 20% active ingredients. Both have the same active ingredients. I tried it once and learned real fast why it was so much cheaper. My last can of BASF that I still have was purchased almost 2 years ago when I discovered predators and never looked back. I can eat a predator bug but I cannot swallow or inhale pesticides.
Amazon.com : BASF Pyrethrum TR Fogger : Insect Repellents : Garden & Outdoor

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Good pic of life stages from k state

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Thats either an adult thrip or a real baby shrimp!

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