Well the cannabis control Nazis at CDFA have forbidden us to use another NATURAL, organic substance to fight mites, pyrethrum. This used to be our go-to for many years. While it is obviously not desirable to spray in late flower, bugs happen (we took over a bug-ridden facility, dont blame us!)
We like to rotate our sprays to keep the little bastards on their toes. Organocide and Plant Therapy for veg and early flowering. Azasol is a great natural pesticide and it’s the strongest Neem product on the market but that is also not permitted by CDFA for whatever silly reason.
Any recommendations? Preferably something light that wont taint the flowers…
There are a few methods you can try that will not impact your pesticide test results. If the infestation is not too large, remove the most infected plants and destroy them. If you have enough labor, you can also vacuum off the mites and their webs (into chambers or bags containing moth balls), and then immediately remove the contents to far away from your grow area. Use a vacuum that isn’t so strong that it damages your plants. For indoor / controlled environments, lower temperatures (well below 70 degrees) and slightly higher humidity will stunt their reproductive growth. If you’re far enough into the flowering cycle, you can check them daily for additional vacuuming, and they won’t have enough time to hatch and grow before you harvest.
For earlier stage infestations, removal of infected plants is essential. Additionally, use of Low PH Water sprays, concentrated vitamin C sprays, or the application of appropriate predator insects and nematodes will eliminate spider mites within a few weeks (the time it takes for the next round of eggs to hatch). Control of the temperature and humidity of the grow area can also help dramatically.
Cannabis plants can also be strengthened to resist pests. Part of this is genetic and is contained within the strains themselves (and through selective breeding and cloning). But most importantly, most plants can achieve relative immunity from pests, based on the long-term health of your soils (the stomach of your plants). Obviously, this does not directly apply to hydroponic systems. Healthy soils take 5-10 years to cultivate, and will last for decades once they’re established. They include the presence of beneficial nematodes & trace minerals, and will foster improved circulation and stem strength in your plants.
All cannabis gardens should contain staging areas for incoming plants, to quarantine new plants and check for potential pest problems, before they enter your nursery or production spaces. Quarantine should last at least as long as an egg cycle takes to hatch (up to 14 days). Garden staff should always change into work clothes and shoes, and wash their hands, before entering into the grow facilities. Spider mites often hitch a ride on shoes and cloths. Adequate filtration (180 microns or less) and ventilation (high pressure blowers at all garden entrances) can also help to prevent infestations.
In closing, check the list of approved pesticides that the State allows, and see if any of those kill egg cycles as well as adults.
It is a bacteria. I haven’t used venerate, but Grandevo was helpful for me, better for early infestations and prevention. The fermentation media for Grandevo is strawberries, so spent strawberries and bacteria. Kind of smells like dark chocolate to me. Venerate is better for established colonies, it work directly on the pest by degrading their exoskeleton. It is also bacteria, but I am unsure of how to smells.
Maybe look into Amazing Doctor Zymes. It can be used through harvest, literally some growers use it even after it’s been cut. It leaves no residues, has no oils, no heavy metals and tests clean. It is OMRI listed. Since it’s not systemic you would need to make sure you hit it a few times. I have heard only positive things from customers who have tried this product. I am sure you can reach out to the company for more info. One thing, you will not want to use it in conjunction with any other pesticides or washes.
Lost Coast Plant Therapy, a blend of oils and isopropyl alcohol is about the only thing I would spray in late flower. It seems to be quite effective on mites while minimizing pistil damage. I recently met the creator of this product and learned that it is increasingly being used in rice and mango production which should result in a price drop. He also advised against increasing strength during a heavy infestation but instead adding and equal amount(1 oz/gal) isopropyl alcohol, however I wouldn’t recommend this late flower.
Trifecta Crop control is also a nice essential oil blend for late flower however it is over double the price ($400/gal!?).
Ive been having the same issue.Venerate and grandivo have been having little to no effect in flower rooms. Use pyrethrins in your veg. to keep them at bay, and make sure you clean your pots and walkways to and from rooms.
The most effective spray Ive seen work in bloom is just safer soap. It kills on contact, but if you miss a leaf they will come back .Predatory mites help but will not 100% eradicate them.
The best you can do imo is try to isolate and control with aforementioned methods. everything else Ive used seems to damage leaves and pistols too much.Stick to that and you should break their life cycle enough for them to disappear.
Pyrethrins are permitted, there is just a threshold of μg/g 0.5 ( micro gram to gram) in the final phase of testing.As an example we tested at 2.4 μg/g in concentrate on first phase 2 testing only in our concentrate, nothing in our flower, and we sprayed up to week 5 in an 9 week bloom.I immediately stopped spraying after first week in bloom and it did not even register in testing.
If you only spray in veg it will not even register or be non existent depending on your grow schedule.
Again it IS permitted but you need to be cautious of your IPM.
edit: Note that concentrates strip the oils( including pyrethrins) and concentrate them, which is why it did not register in the flower.
Essential oils are great for control in late bloom, but they can change your terpene profile . Rosemary has rosmeric acid in it that eats away at the mites cuticle for example. although not all essential oils are effective, so finding a proper mix and balance may take time.
Here is a list of what the labs are required to test for and the ppm thresholds.Some of them are out right banned, but most of them are just the thresholds. The math trying to figure out how much and when you could use some of the permitted substances you can use hurts my head.Hopefully this should give you a little perspective on what to watch for . Scroll down to page 23. https://www.bcc.ca.gov/law_regs/mcrsa_lab_ptor.pdf
I have been working closely with the CDPR and just renewed our pesticide use permit last Friday.If you want some help working on your IPM shoot me a message and I can help .We are !00% organic and Clean Green certified as well.
I hate cannabis damageing bugs.
Had good luck with Venerate. Mites now under control. Even if small amounts of pyrethrins are permitted, how could i know where the threshold is? Not really worth risking a crop…
Well, here is a Bayer product that works exceptionally well. Brand name Movento, chemical name spirotetramat. Labeled for many crops but as a example…tomatoes: 1 day preharvest interval. Controls russet mites and broad mites. application rate is very low 4-5 oz per acre. Problem is it’s only available in qts and will set you back about $1,000. Also want to point out that pyrethrins are not that effective on mites anymore…they have built pretty good resistance over the years…FWIW
