They are arachnids (relatives of spiders), and like other arachnids, they have four pairs of legs and no antennae. Their colors range from red, brown and black to yellow and green de- pending on the species and the time of year. Spider mites are so tiny though that most of these details are visible only with a magnifier.
Spider mites make silk, hence the name spider mite. The two-spotted spider mite, the spider mite most likely to attack cannabis gardens, has two dark spots visible on its back when it is an adult. How to spot Spider mites and what they do to the cannabis plant. They live on the plants, mostly on the underside the leaves, but can be found on the buds. They can also be found moving along their silvery webbing, from leaf to leaf and even plant to plant. Spider mites pierce the surface of the leaves and then suck the liquids from cells. These punctures appear on the leaves as tiny yellow/brown spots surrounded by yellowing leaf. They can be seen as colored dots on the leaf undersides. As the population grows they produce webbing that the mites use as a protective shield from predators, a nursery for their eggs and a pedestrian bridge between branches or plants.
They are more of a threat than most pests because of their high rate of reproduction. Spider mites are by far the most fearsome of all plant pests. They are most active in warmer climates than cold ones. Reproduction rate and life cycle: Newly hatched mites are 3:1 female: male, and each female lays up to 200 eggs, 1 to 5 per day, as an adult. This life cycle can repeat as often as every eight days in warm, dry conditions such as a grow room. Spider mites spread through human transport as well as by wind in out- door gardens. Because of their rate of reproduction and the short time from egg to sexual maturity, a spider mite population can explode with shocking speed. Almost all spider mite infestations enter the garden on an infested plant, through the ventilation system or by gardeners who carry the hitchhikers into the garden. Use a fine dust filter (at least 300 microns) in the ventilation system, and never enter the grow space wearing clothing that has recently been outdoors, especially in a garden. Neem oil is often used as a preventive, but always look out for webbing and for the yellow-brown spots mites leave when feeding. Infected mother plants transmit mites on their clones, so it is especially important to watch for mites in a mother room. When you spot mite symptoms take action immediately. Growing from seed in an indoor environment is a great start to prevention in an indoor grow space. Don’t introduce plants from other spaces or quarantine new plants for several weeks. Increasing humidity in the vegetative and early flowering stages can slow population increase. • Insecticidal soap kills many of the mites, lowering the population and the damage, but does not eliminate the population. • Pyrethrum is effective against some mite populations, but others have developed immunity to it. Get those best suited to the environment of the garden. Apply predator mites at the earliest sign of infestation. Most predator species reproduce faster than spider mites, but if the mites get a good head start, the predator population can never catch up. Even in optimal conditions, control with predator mites is very difficult.
Four effective species are Phytoseiulus persimilis, Amblyseius swirskii, Amblyseius fallacis and N.
Persimilis is the first predatory mite ever used as a pest management product, to attack Two Spotted Spider Mites and Pacific Spider Mites in both Vegetative and Bloom State. These Type I predators only have one prey and can eat 35 food unites (a spider mite egg or adult) per day while laying 4-7 of their own eggs. They are extremely ravenous but need 70% relative humidity for their eggs to hatch, making them a great predator for hot spots with larger infestation problems.