Pretty sure I know the answer to the question but I still wanted to check with more experienced people.
The critters seem stationary (sucking on the root) rather than pacing around. I have had those ‘Mg defficiencies’ even though I give close to 100ppm of Mg.
On the last pic I think I’ve captured an adult winged one even though it might be a fungus gnat.
Thanks
Yep, spawns of satan right there. Horrible pests.
Yes. Get yourself some Botanigard 22WP.
I’m not in the US. Locally I can get another Beauveria bassiana product called Naturalis, but Imidacloprid and Acephate are banned by EU and are not easily accessible.
Should I drench only or foliar spray too? Does anyone have experience with dipping the whole rootzone in insecticidal soap etc.?
Diluted peroxide would do the job if you drench the roots with it, but it kills all the microbiota so if running organics you should repopulate it … 
Can you give me a ratio (I’m using 30% h2o2) and should I dunk for some time for better effect?
Thank you
I know the ratio for 3% hydrogen peroxide, I suppose with 30% should be much more diluted, do some testing before… 
Just had my first run-in with these critters… they got my PCF Midnight Mass in week 8 of flower. At first I thought it was a ph or maybe overwatering … leaves started wilting … left it to dry out a bit for 2 days, and today every leaf was wited and dead, starting to dry. Reservoir had plenty water. I got it and the SIP it was in out of there, and trashed it. The rootball came out with a gentle tug (they usually take quite a hard twist and yank) and was obviously eaten up, a closer look confirmed the culprit. I blame some homemade compost/castings I top dressed with, combined with high temps due to summer heat with super humid conditions requiring a dehumidifier heating the air a lot. The other plant of 2 in the space shows no symptoms, it needs 2 more weeks so I’ll be watching carefully and using some H2O2 solution to water in.
This is the best solution and I have relied on it many times , I’ve seen hydrogen peroxide kill plants and wouldn’t recommend it although it works for some. Fighting nature with nature always seems best , this reminds me to order some more for the mothers before winter arrives , bastard fungus gnats show up every year when it starts to cool off.
I like to use it even when I don’t have critters as part of a good pest managment/ prevention program
Have you ever had an infestation you eliminated with Hydrogen peroxide? How did the plants do?
I’ve used peroxide to eliminate root aphids. It was one of my early grows and I panicked when I found them. I ended up pouring a pint of (straight) 3% H2O2 on them. I follow that by a pint of water. The plant bounced back and ended up doing good.
Nope, I just remember reading it online, I guess you can start with a low dose, see how the plant reacts and increase if needed, boiling water also works …
Root aphids reproduce via clone. To eliminate them from your space you need to remove all the plant material for a week or two. Take cuts of plants you want to keep, clean them really well in your choice of plant wash. I like Tweetmint but others would work fine. Clean them, then clean them again.
Take a shower and change your clothes. Take your clean cuts to another area of your house far away from the grow room. Dunk your plugs into the Naturalis or whatever beauveria bassiana product is available to you. If there are any left they’ll get smoked while rooting up. By the time you have rooted clones the root aphids should be gone. Best of luck and let me know if you have any questions. I’ve vanquished them and you can too.
Root aphids do not produce an egg stage indoors from the research I’ve done. You just need to take away the host plant and they will go away.
I’ve seen so many people try to fight them in huge pots without ever taking a break and they just stick around. You need to break that cycle by removing all cannabis plants from the grow area.
Best of luck and let me know if you’ve got any questions.
Do you have fungus gnats?
Pretty sure those are their babies
Edit. I saw you said you have them. Yes those are fungus gnat larvae.
I had them bad as well. Just cover your top soil in sand. Solved my issue better than anything
The larvae cut their bodies on the sharp sand and die. And it also keeps them from laying the larvae because the sand isnt habitable. I was amazed how well it worked. I have a stray few once in a while but not an issue like it was.
Just keep your soil a bit on the drier side and put an inch or so layer of sand on top. Promise it will solve your issue.
Ps if you need to top dress anytime in the next week or so Id just do it now before you lay the sand down.
I had 2 earth boxes side by side, one had them and that plant died fast, the other seems fine. I removed the pant and infected EB from the area pronto. So you think there’s no way they spread to the “good” plant? I put out sticky yellow strips but so far have no flyers of any kind.
EDIT: I researched heavily and, so far, literature confirms the fungus gnat and root aphids are two separate species. No?
Root aphids and fungus gnats are two totally different species and are often confused.
In theory, if I remove all plant material and soil from the equipment (tents, fans, pots) and remove the plants, the RAs will be gone within 2 weeks? Don’t I have to disinfect the surfaces too?
