
[SIZE=-2]Image by: Green Shaman[/SIZE] Let me first start out by offering you my sympathies... mites are one of the worst pests you can encounter while growing cannabis. They can reproduce at a phenomenal rate and easily have the potential to ruin your flowering crop, nay all your plant material IF you aren't vigilant about getting rid of them.
Scared yet? You should be! Hopefully this will wake you to the seriousness of the situation; trust me you don't want to see a full blown mite infestation. Not a pretty site. That having been said, if you take care and understand the life cycle of the mites, you should be able to rid yourself of them quite easily.
The Environment
Mites have a life cycle that varies directly with the environment... in a very hot, dry climate they can complete a life cycle in a few weeks. If the environment is cooler, and has more humidity, it can take them over a month to hatch, mature and leave their own offspring for the next wave of attacks on your plants.
This is very important to understand, because it's easier to destroy the population if there aren't new ones popping up as fast as you can kill them.
So your first goal is to make the environment less hospitable for the evils... drop the temps as low as possible, and increase the humidity in your grow chambers. An evaporative cooler should help.... this can be as simple as a bucket with a fan pointing across the water. Stale air is a no no as well, so get some good fans constantly blowing across your plants (making it very difficult for mites to lay their eggs) and increase the ventilation if possible... depending on your setup, this should also help drop the temps, but may decrease overall humidity.
Biological Controls
You can go bio and use predatory mites. Phytoseiulus persimillis is a voracious mite that feeds on the evil mites, but won't eat your plants. When they've eaten all the mites they can find, they run out of food and die.
If you choose to go this route, use one of the chemical sprays mentioned below (to knock down the spotted mite population), but discontinue it's use a week before introducing the predators; which are themselves susceptible to the chemical sprays.
*Studies have shown that mites were able to elude the persimillis by hiding in various nooks and crannies around the garden, only to return to and take over again when all the predators had died.
IF you do use predators, a time-release is recommended... add another dose to your plants each week for a month just to make sure you've got some fresh predators to hunt down any re-occurring mites that have been missed. The predator mites will eat all life stages of evil mite, from egg to adult. Adding predators can get expensive; only the truly organic tend to use this route.
Check online to find a cheap source of predators; a Google search for "predatory spider mites Phytoseiulus persimillis" should yield numerous places to purchase.
Environmental considerations for predator mites:
The environment plays a big role in biological predator mite control. In general, ?evil? mites prefer a HOT + DRY climate; the predators prefer a COLD + HUMID climate.
If you put the preds in a hot dry climate, the evil mites will out reproduce them, and the predators won't reproduce fast enough to kill them all. Same opposite for a colder/humid room... the predators will easily out reproduce the evils, and will have a much easier time of taking care of the problem.
Introducing predators to a flowering (12/12 light cycle) chamber is essentially futile according to leading cannabis researchers... the predators seem to just go to sleep. They are more suited to the longer light cycle in a veg room.