Spider mites help

[Smeden]

Hi all

My greenhouse has an infestation of small red gnats, which I initially thought was in family with Aphids, but when I looked under microscope today I saw a happy red spider mite spinning its web. Have a nice video, but cannot upload it here. Greenhouse has good ventilation = I cannot see any webs or the small mofos cannot make the web due to wind, but still happy without the web?
I have tried Neem oil, Spinosad and another "safe" insecticides clearly without luck.

Location is Thailand (12 degree N)

All plants are 5 weeks into veg and I plan to veg them another 4-5 weeks = I should be able to "nuke" them now and consider the flower safe some 15-20 weeks later?

Suggestions on treatment/chemicals are very welcome. I have had spider mites many times before, but these red guys thrive no matter what I try.

Pics:

This fellow is making a web between 2 leaves under the microscope.

 

[Creeperpark]

I'm sorry you are having this problem friend. Red spider mites, also known as two-spotted spider mites are hard to get rid of. They breed so fast and lay eggs every day making it hard to kill all the different groups, "eggs, adolescents, adults". You have to bomb or spray every 3 days to kill the new hatchlings.

Since you are in a greenhouse you can use commercial foggers or pyrethrum bombs with 40% active ingredients. If you use commercial bombs every few days they will go away. The pyrethrum has to hit under the leaves for it to work and spraying only on the top of plants misses too many. It can take a while to get them under control using bombs but they work in greenhouses that can be sealed up. Good luck

 

[Creeperpark]

Red spider mites tend to multiply and attack plants when the weather is hot and dry. That's why they are found indoors all year round and in the garden in summer, when it doesn't rain and temperatures stay above 70°F (20°C) Google

 

[flylowgethigh]

I use a solution 'Green Clean' and add a capful of ready to spray neem oil to the solution. Better get on them, those look like they are pretty established. Spray daily just before lights out until the bastids are dead, dead, dead.

 

[gmanwho]

with any bug or spore, or pathogen, you gotta learn the pathogens life cycle and interrupt it before they can reproduce. continue applying long after any are seen in hopes of getting every last egg or spore to hatch.

i am not sure about the red spider mite, but i have read that the eggs of 2 spotted spider mite we often see can lay dormant for 2yrs or more.

And as creeperpark mentioned, when applying a good fogger helps. the chaotic wind moves the leaf around and will expose both sides of the leaf, all the stems, and your surrounding greenhouse structure.

how you treat them comes down to what your comfortable spraying. I tend to stay away from watering in systemic chemicals to the medium. my take from what i read is when the chemical gets into the soil or coco or rockwool, the lack of oxidation or the exposure to atmosphere(oxygen) increases the chemicals half life. in some case's the half life is extended very very drastically. The oxidation rate is slowed when the chemical is buried beneath the soil,drastically. Exposed to the air it breaks down significantly faster.

so it is possible that a harsh chemical foliar sprayed or dunked (instead of watering in) when the clone is 3 inchs tall will be long gone 100 days later in flower.

after a few harsh treatments, and i know i have gone over everything in the room, multiple times, i goto something less harsh like mpede or suffoil x as a preventative. which then becomes a bi weekly procedure whether i see bugs or not.

This way you knock down the problem, and then use things that are less harsh from then on. But you have to be mindful and keep to a program of applying. otherwise they will always return.

 

[gmanwho]

getting into bio fungicides can be a good after you have gone nuclear.

also its damn near impossible to keep a perpetual garden going as whatever your spraying should not be on your buds.

another thing important to note is when it says its safe for vegetable or next day harvest , REMEMBER you dont smoke tomatoes or squash corn or beans. so a spray that is safe to eat, maybe veryyyyyyyyyy veryyyyyyyy different once its goes through the chemical change that happens during the heat process when smoked! very important, and 99% of the time this is over looked. i can not stress that enough.

 

[Cuddles]

I used to have tons of spider mites when I moved into my flat ages ago. I wasn´t even growing cannabis at this point, I just wanted some plants to make the place look nice. No matter which type of plant I put in , or out on the balcony, they were all murdered by the borg. Then, when I thought I had gotten rid off them and did grow pot, guess what?
I asked a florist and they said that hygene is vital. So before you even think about your next grow, clean the place as though it is a surgical operating room, including all the pot, equipment etc.

I once also read that to get rid of the borg you can use plain water. What you do is, you turn the plant upside down and wash it thoroughly. Putting it head first into a bucket of water is also a good idea. The mites are very often underneath the leaves, not just on top of them
However, I´m not sure this will be much help (it didn´t save my plants back then) as they´re already pretty far along ie spinning webs.
They don´t like water and moisture, so for future grows it may be a good idea to provide them with humidity, as well as spraying them all over incl. the bottom of the branches and leaves. For passive humidity you can place clean containers with clean water all around the greenhouse. In your part of the world it´ll probably evaporate very easily .

I´m sorry for the long post which offers no immediate solution to your problem but I have always been afraid of harsh, nasty chemicals which could not only damage the pests, but also my own health, which is why I mention the water solution.

 

[Ca++]

Covid saw a lot of cheap foggers brought to market. Fog so fine a fan will carry it. You can also get electric spray guns for fences and such. Look like air powered spray guns at the paint shop, but plastic. They can make fog from thicker solutions. You could think about RO water (battery top up water) and softening it further with some insecticidal soap. Mites drown. They have a tiny breathing hole, they can't close. Water surface tension saves them when it rains, but many die still. If we soften the water, reducing surface tension, it just gets straight in. Drench them every 2 days to kill the hatched ones. You could stray every day, but I find plants don't like that much water pumping in. The plants also take on this water with less control than they have with rain.

Ideally drunk plants for a good 30 seconds, but you can't always do that. I have never failed with water and a wetting agent. While others seem to fail with nuclear bombs. It's all about proper application. You need a wet water fog.

 

[Smeden]

Thanks for all the good inputs.

It is not the first time I have enjoyed spider mites, thrips or aphids, but these 2 spotted devils are a nightmare.
They showed up during my last grow, but mainly attacked a Durban Poison from Dutch Passion - like a magnet. Some genetics like Amnesia Lemon Haze are nearly unaffected. So I guess I need to consider this when selecting future green house genetics.

It is dry season now and our lawn is brown without a single green grass straw.
I have 3 green houses, each of 3x2m with a 18" fan and MH SP150 LED light for vegging.
Floor has a double plastic membrane + artificial grass = I think I could start hosing the hole place down and the water trapped on the floor will raise the humidity by a lot until evaporated.
To use a fogger I would need to buy extraction fans for each tent and close the doors during daytime. With open doors and full sunshine the temp goes as high as 45C, so if I close the doors I will need an extraction fan in each tent.

I am a new to green house grows, or say very new to it in a tropical climate. Tons to learn, but the plants are vegging nearly double speed of indoor with LED. So I am not giving up yet.

I think I will buy 3 x 8" silent extraction fans to suck out warm air from the top. Add foggers and ensure I raise the humidity as much as I can the next weeks + continue the Spinosad spraying daily.
Humidity might be my biggest problem, as everything has been bone dry for weeks.

 

[YellowCanaryConsulting]

Spider mites are attracted to plants with abundant levels of free ammonium in the sap.

Elevated levels of ammonium often occur in high temperature environments when plants shift from photosynthesis dominant to photorespiration dominant. When this shift to high photorespiration occurs, plants are no longer getting enough energy (sugars) from the photosynthesis process (which has slowed down or halted). To sustain themselves, they begin catabolizing proteins (amino acid nitrogen) to use as an energy source.

The protein catabolism during photorespiration in high temperature environments usually results in the accumulation of ammonium in the leaf, which can result in the crop being susceptible to spider mites..

BUT.. this happens ONLY when the plant does not have the needed nutrients and enzyme cofactors to convert the ammonium back into amino proteins at night, or as soon as carbohydrate energy become available.

The critical nutrients for this conversion process are magnesium, sulfur, boron, molybdenum, adequate carbohydrates in the plant, and occasionally nickel.

 

[Smeden]

Spider mites are attracted to plants with abundant levels of free ammonium in the sap.

Elevated levels of ammonium often occur in high temperature environments when plants shift from photosynthesis dominant to photorespiration dominant. When this shift to high photorespiration occurs, plants are no longer getting enough energy (sugars) from the photosynthesis process (which has slowed down or halted). To sustain themselves, they begin catabolizing proteins (amino acid nitrogen) to use as an energy source.

The protein catabolism during photorespiration in high temperature environments usually results in the accumulation of ammonium in the leaf, which can result in the crop being susceptible to spider mites..

BUT.. this happens ONLY when the plant does not have the needed nutrients and enzyme cofactors to convert the ammonium back into amino proteins at night, or as soon as carbohydrate energy become available.

The critical nutrients for this conversion process are magnesium, sulfur, boron, molybdenum, adequate carbohydrates in the plant, and occasionally nickel.

Thanks, all makes sense. So what do you suggest?
I think/hope raising the humidity by foggers or similar will be the most important next step? but can only do when I also add extraction fans in each greenhouse to suck out the warm air from the top and closed door.

 

[Ca++]

When I speak of foggers, I mean decent spray guns. It's not for RH control, it's how to wet every millimeter of the plant. If just one lives, the treatment will offer control, but not eradication. We need to kill the whole fecking lot of them, before flower. Once in flower we don't want to spray them at all.

Some of the toy one's are ultrasonic, and won't deliver things like neem.
The paint gun works with quite viscous solutions. Oddly, the cheapest 'clark' one I got was great, and the fancy one went back as useless. They blow the plants about, so it gets everywhere.

Treatment between crops is best. Cuttings are easy to dunk, and rooms can be hit with many things, while there are no plants

 

[Cuddles]

When I speak of foggers, I mean decent spray guns. It's not for RH control, it's how to wet every millimeter of the plant. If just one lives, the treatment will offer control, but not eradication. We need to kill the whole fecking lot of them, before flower. Once in flower we don't want to spray them at all.

Some of the toy one's are ultrasonic, and won't deliver things like neem.
The paint gun works with quite viscous solutions. Oddly, the cheapest 'clark' one I got was great, and the fancy one went back as useless. They blow the plants about, so it gets everywhere.

Treatment between crops is best. Cuttings are easy to dunk, and rooms can be hit with many things, while there are no plants

a paint spray gun is a brilliant idea !

 

[gmanwho]

Another thing to consider is air filters on any intakes. seal cracks and where structures come together. use tangle foot at the base of plants or container rims and any stakes.

It is also Important to note that a flying insect can carry eggs, smaller bugs, or spores from outside. Then those flying bugs move from one plant to another and can easily spread pathogens around. remove standing water.

I tried inserting a photo here, but i cant seem to find it. It is a magnified photo of a fungus knat, or other flying insect, with broad mites hitching a ride on the flying insect legs. Creepy, but eye opening.

With a greenhouse , im assuming your structure could be of decent size, if so you should take the fact that a smaller hand held sprayer that holds a 1/2 gallon of spray will not go far.

 

[Cuddles]

Another thing to consider is air filters on any intakes. seal cracks and where structures come together. use tangle foot at the base of plants or container rims.

It is also Important to note that a flying insect can carry eggs, smaller bugs, or spores from outside. Then those flying bugs move from one plant to another and can easily spread pathogens around. remove standing water.

I tried inserting a photo here, but i cant seem to find it. It is a magnified photo of a fungus knat, or other flying insect, with broad mites hitching a ride on the flying insect legs. Creepy, but eye opening.

With a greenhouse , im assuming your structure could be of decent size, if so you should take the fact that a smaller hand held sprayer that holds a 1/2 gallon of spray will not go far.

so you don´t recommend placing water containers around the greenhouse in order to increase humidity in it?
What if you relace the water regularly?

 

[Cerathule]

If you use chemicals, you need to combine, at least 2, better 3 different ones or some mites with resistance are going to survive, and become the next established population that is already immunisized. It´s not unrealistic to assume your current population is. Plus it´s not enough to just buy 3 differently labered mitekillers - the chemicals need to work via a different mechanism to kill the critters.
Not sure what is allowed in your country... been using spinosad, dimethoat and permethrin... I wouldn't spray in flower... then there's diatomacious earth dust that kills all insects but is also a no-go to put on resinous flowers

Treatment between crops is best. Cuttings are easy to dunk, and rooms can be hit with many things, while there are no plants

This is very good advice.

Also think about how to prevent another re-infection. These mites can start out with a sole single egg or creature.

 

[Cloneman]

 

[Cuddles]

View attachment 18815588

is this from the X-files, or from Men In Black, lol

 

[zachrockbadenof]

BUT.. this happens ONLY when the plant does not have the needed nutrients and enzyme cofactors to convert the ammonium back into amino proteins at night, or as soon as carbohydrate energy become available.

so if the plants have the proper nutes...no mites.... sorry, but i don't believe that... i have had plants that were healthier then shit... and still had mites... thoses fukers are everywhere..

 

[flylowgethigh]

My #1 best cure for SMs, and dusty dirty weed, is the forced filtered air. A little bit of positive pressure. And vacuum the carpets once in a while. In other words, prevent the bastids.

I also look really close at the leaves I cut off, underneath nearer to the stem, for amber eggs. If leaves get discolored, it is probably SM, and get in there and look at the leaves.. If you get PM, it is hand in hand with SM. IMO. But by then it is time to spray.