Symptoms and care of both russet & broad mite damage are essentially the same; broad mites are just a lot more common in cannabis. These types of mites are insidious! They cunningly lay their eggs inside the actual leaves, and are less than microscopic in size: 1/150th of an inch!
— How do you identify it?
These little guys are hard to see, so growers most likely won’t see the actual insects.
Symptoms of russet and broad mite infestation include: glossy, wet-looking, bubbled/blistered, plastic-appearing, twisted leaves. Cannabis flowers can turn brown, wet and soggy, and affected leaves eventually turn brown and detach.
— DANGERS!
Broad and russet mites are even harder to detect than spider mites, because they are so tiny! Growers will see symptoms, but not necessarily bugs; russet and broad mites are even difficult to see with a microscope. Many growers will mistake a russet/broad mite infestation for overwatering, tobacco virus, or heat damage.
— Treatment
Broad mites lay their eggs INSIDE cannabis leaves. This makes them extremely difficult to eradicate completely! Treat your plants with IMK for six weeks after initial treatment to be certain. Whichever pesticide you use, try to aim for fifteen minutes before lights out, so the affected leaves don’t burn! If your plants are suffering from consistent pesticide use, consider supplementing IMK with diatomaceous earth. A varied approach is, again, best with russet & broad mites.