Mites. Dichlorvos. Neem.

I recently discovered spider mites setting up shop in my room while transferring plants from veg to flower.

No webs yet. I noticed the tell tale bites and when I flipped the leaves over I saw them. Little black dots, some egg pouches.

I have never had a mite problem before.

I cracked the seal on my pure organic Neem oil and mixed solutions in a 500mL bottle.
- ~500mL warm water
- 2-3 eye droppers of neem oil
- just enough soap (Shaklee Basic H2 biodegradable) to allow the oil to mix in with the warm water

Pulled all the plants out of the room & sprayed all plants thoroughly from the underside first and then from the top side until they where drenched and then some. Also sprayed the top 'soil' and the fabric pots.

I cleaned out the room, sprayed it down as well after.

I have read that lower temperatures and a light schedule less than 12 hrs of light help to slow down the process of the hive.

I raised my lights because I heard neem can make plants sensitive to light and turned up my exhaust and intake to keep temperatures down to 20-23*C / 68-73.4*F during lights on and 17*C / 62.6*F during lights off.
I also adjusted my light schedule to 11/13 in the flower area.

The next day in the flower area my plants are all curled and haggard looking. The fan leaves are super clawed and curled. The newer growth is all thin and twisted. A lot of the new growth also looks like it had light bleaching. Death looked imminent.

After seeing this I sprayed down all the top side to drenching with plain water right after lights out to wash off any residual neem oil on the top of the leaves.

I replaced my flowering lights to a 400W hps from a 1000W. Left them for another day. They looked like they where starting to recover. Most of the black speck mites are gone from the undersides of the leaves.

Fan leaves are still curled. New growth still looks like shit. But death it seems is not at the door any longer.

I have my lights at an elevated hight still, about 2ft from the top of the plants but back at normal wattage.

I have purchased NO PEST STRIPS. I will be installing them tomorrow. The grow room is detached from house. I plan to use the strips for a week or until I see no sign of the borg.


Now here is where the forum comes in. Can any one help me understand:

Why do my plants look this way after a single Neem oil session?

Will they recover? What can I do to assist them? (Looks almost like N toxicity 'claw' to an extreme without the burnt tips on the fan leaves and heat/light stress on the new growth).

Would a flush help?

How long does it take for the active chemical compound Dichlorvos to break down and be gone from my plants and grow room?
(I am researching this still on the net and am having difficulty tracking down a positive answer on this. I will actively be researching this chemical and post any findings here as well).

Thank you RIU.

Your supposed to take them away from fans and light untill the neem is gone. Try a few cfl's with the same neem mixture for a couple days and dont blow air on the treated plants. Mites really aren't too hard to get rid of with miticides and frequency water but with neem on an already damaged plant, they will usually just jump back on for the ride a few days later.

Morbid Angel said:

How long does it take for the active chemical compound Dichlorvos to break down and be gone from my plants and grow room?
(I am researching this still on the net and am having difficulty tracking down a positive answer on this. I will actively be researching this chemical and post any findings here as well).

Click to expand...

I found the answer to this and the most informative web page issued as a public health statement on Dichlorvos the active ingredient in 'NO PEST STRIPS'. The answer to these questions I will copy and paste from the original statement which can be found here: Agency for Toxic Substances & Disease Registry: Public Health Statement for Dichlorvos

- 1.3)
It has been recommended that people should not reenter a room or house treated with dichlorvos until after a 10- hour ventilation period.

- 1.2)
Dichlorvos enters the air, water, and soil during its manufacture and use. Wastes containing dichlorvos that are generated during its manufacture and use are sometimes disposed of in landfills. It can enter the environment from these landfills. Dichlorvos also enters the environment from accidental spills during transport and leaks from storage containers.

Dichlorvos evaporates easily into the air, which is why it is usually used in enclosed areas. Once in the air, it can react with water vapor and be broken down. The higher the temperature and the humidity, the more rapidly dichlorvos is broken down. Experiments in greenhouses and food storage areas show that 90% of the applied dichlorvos disappeared in 3–6 hours. The products of this breakdown are two chemicals called dimethyl phosphate and dichloroacetaldehyde. These chemicals are less harmful than dichlorvos and are not believed to cause health effects in people.

If dichlorvos is spilled into a lake or river, it will dissolve in the water. Some dichlorvos will then evaporate into the air, but most of it will be broken down when it reacts with the water. The less acid the water is, the more rapidly dichlorvos is broken down. Bacteria and other microorganisms (microscopic plants and animals) in lakes and rivers can also break down dichlorvos. In an experiment where dichlorvos was applied to a pond, 50% of the chemical was broken down in 24–36 hours.

Dichlorvos does not seem to bind to soil. This means it can move through soil fairly rapidly. The breakdown in soil is less rapid than in air or water. Dichlorvos breakdown is most rapid in moist soils with low acidity. In a laboratory experiment with soil that contained 200 parts of dichlorvos per million parts of soil (200 ppm), 37% of the dichlorvos remained in the soil after 3 days. Dichlorvos remains for longer periods in dry, acidic soil. Certain bacteria and other microorganisms in the soil can also break down dichlorvos.

Dichlorvos is not stored, accumulated, or concentrated by plants, fish, animals, or people.

I dont think I would ever use neem oil again. Damn near killed my plants. Yield and growth came to a screeching halt. BOO!

forbid 4f did the trick for me. one spray in veg, then one more as they go into flower. i ve got other sprays(nuke em, neem) but forbid is effective and easy.

As a heavy user of neem oil, it depends on how well u use it , I usually put arnd 5ml oil in 1 litre

And spread it over every leaf and part of the plant possible, but my problem was worst it was scale infestation neem jus keeps them at bay

Mighty wash or Flying Skull nuke em , use them anytime, the nuke em is even a natural fungicide.

I have a hard time understanding why in your case the spraying with Neem would have hurt the plants.
I am spraying my plants with Insecticidal (potassium) soap and Neem *liberally* and often and I have never seen any problems with this whatsoever.
Please read my thread here: https://www.rollitup.org/t/how-to-kill-and-keep-off-almost-all-common-mj-pests-easily.900261/

I looked over your post and the "soap" you're using there seems suspicious to me. First, it doesn't even say that it's an actual *soap* so I doubt that this can even create an emulsion for the oil to mix in. Secondly it's described more like an "all-purpose cleaner" which can even "irritate eyes" and whatnot...nothing I'd spray on my plants under all circumstances.

I just think it's unfortunate that you say you won't ever use Neem again since I consider it VERY safe, and before you switch to hardcore chemicals like forbid etc. I think you should really try to give this another go, with an actual insecticidal soap and Neem like I do.

** I also want to add I would not get actual Neem oil since those are often made for cosmetics and do often not even come with instructions about how to use them for plants. I am only using Neem oil products (insecticides) that contain clear instructions for dosage. Products like Azamax or whatever products available based on Azadirachtin. (The one I use is some local brand "Align" that comes in a 15ml flask, 3.2% Azadirachtin and where you use 0.1-0.125% per emulsion.) I wouldn't get "pure Neem oil" on ebay etc. and then just guess on how much you need to use for sure.

If there is a next time, I may try one of your suggestions.

I have used the soap I mentioned in foliar before with no issues. I also mix it in to the feed water with no issues.

It was the neem. It may be because I didnt reduce the light intensity or fan speed enough which caused the problems. Seems that you are supposed to remove them from HID and moving air while treating. Could be that it was too strong a dose.

the solution was emulsified. I followed recipes to the best of my research. I think it was 5ml / L? I dont remember.

If I battle it out again, I am more prone to cutting the plants and starting over after disinfecting and cleaning the room, then trying to fight mites with sprays. If I was running a warehouse then it would be different. The gods know I have enough cuttings kicking around to kickstart a warehouse.