Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

This is the most important first step to spider mite control. Keep the grow room and tools spotless and disinfected. Mother plants often have spider mites. Spray mothers regularly with miticides, including once three days before taking cuttings. Once mite infestations get out of control and miticides work poorly, the entire grow room will have to be cleaned out and disinfected with a pesticide and 5 percent bleach solution. Steam disinfection is also possible but too difficult in most situations.
    Cultural and physical control: Spider mites thrive in a dry, 70-80°F (21-27° C) climate, and reproduce every five days in temperatures above 80°F (27° C). Create a hostile environment by lowering the temperature to 60°F (16°C) and spray foliage, especially under leaves, with a jet of cold water. Spraying literally blasts them off the leaves as well as increases humidity. Their reproductive cycle will be slowed, and you will have a chance to kill them before they do much damage. Manual removal works for small populations. Smash all mites in sight between the thumb and index finger, or wash leaves individually in between two sponges. Avoid infecting other plants with contaminated hands or sponges.
    Remove leaves with more than 50 percent damage and throw away, making sure insects and eggs do not reenter the garden. If mites have attacked only one or two plants, isolate the infected plants and treat them separately. Take care when removing foliage not to spread mites to other plants. Severely damaged plants should be carefully removed from the garden and destroyed.

Keep relative humidity below 50 percent to discourage bud mold.

If plants are infested with spider mites, lower the temperature to 60-70°F (10-21°C). This temperature range will slow their reproduction.
    Smear a layer of Tanglefoot™ around the lips of containers and at the base of stems to create barriers spider mites cannot cross. This will help isolate them to specific plants. Note: smear a layer of Tanglefoot™ at each end of drying lines when hanging buds to contain spider mites. Once foliage is dead, mites try to migrate down drying lines to find live foliage with fresh, flowing sap.
    Biological: Neoseiulus (Amblyseius) californicus and Mesoseiulus (phytoseiulus) longipes, are the two most common and effective predators. Phytoseiulus persimilis, Neoseiulus (Amblyseius) fallacius, Galendromus (Metaseiulus) occidentalis, and Galendromus (Typhlodromus) pyri predators are also available commercially.
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Progressive Control Measures for Spider Mites
    Cleanliness - Clean room daily, disinfect tools, do not introduce new pests into the garden on clothes, no animal visits, etc.
    Create hostile environment - Humidity, temperature, water spray.
    Create barriers - Smear Tanglefoot™ around pot lips, stems, drying lines.
    Dip cuttings and vegetative plants - Dip small plants in pyrethrum, horticultural oil, neem oil.
    Remove damaged foliage - Remove foliage more than 50 percent damaged.
    Introduce predatory mites - Release predators before infestations grow out of hand.
    Spray - Apply pyrethrum or neem oil; use strong miticides only if necessary. Rotate sprays so mites do not develop immunity.
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    When properly applied and reared, predatory spider mites work very well. There are manythings to consider when using the predators. First, predators can eat only a limited number of mites a day; the average predator can eat 20 eggs or 5 adults daily. As soon as the predators’ source of food is gone, some mites die of starvation while others survive on other insects or pollen. Check with suppliers for release instructions of specific species. A general dosage of 20 predators per plant is a good place to start. Predatory mites have a difficult time traveling from plant to plant, so setting them out on each plant is necessary. Temperature and humidity levels must be at the proper levels to give the predators the best possible chance to thrive. When spider mites have infested a garden, the predatory mites cannot eat them fast enough to solve the problem. Predatory mites work best when there are only a few spider mites. Introduce predators as soon as spider mites are seen on vegetative growth, and release them every month thereafter. This gives predators a chance to keep up with mites. Before releasing predators, rinse all plants thoroughly to ensure all toxic-spray residues from insecticides and fungicides are gone.
    The fungus, Hirsutella thompsonii, trade