BROAD MITES, HEMP RUSSET MITES, & ERIOPHYID MITES (Polyphagotarsonemus latus, Aculops cannabicola, & Aceria anthocoptes)
While Spider Mites, Aphids and Gnat Fungus have long been a headache for cannabis growers, Broad Mites, Russet Hemp Mites, and Eriophyid Mites are relatively new to the scene. They are less common, but some growers have had problems with them. They’re also a trio which you’ll only find on indoor crops, and, more concerning, evidence of their pesky selves typically becomes apparent once the plants have matured. Then you’ll see leaves and stems turn bronze and feel greasy.
With these three, prevention is better than cure, indeed it’s your only real option if you wish to keep using biological controls.
NATURAL ENEMIES OF BROAD MITES, HEMP RUSSET MITES, & ERIOPHYID MITES
Amblyseius fallacis is your best option for prevention of this trio. Amblyseius fallacis also helps prevent Spider Mites from developing into a problem.
As soon as you see the first proper leaves begin to grow, then you’ll want to release Amblyseius fallacis. 2 mites per square foot should do the trick, although you should release at a rate of 4 per square foot if you’ve had trouble with these mites before.
The good news is that when you cannabis plants begin to grow their sticky heads, these mites, and others, will begin to move away.
Another good preventative mite is Amblyseius cucumeris, but it will deal with this trio in their early stages of development. So get in there early.
Amblyseius andersoni mites are to be used once you’ve already spotted adult Russet Hemp Mites. Amblyseius andersoni is most effective when the colonies are small. These predatory mites will eat small colonies and stop them from growing and hopefully prevent serious damage.
Californicus (Neoseiulus californicus) The clue’s in their name, these predatory mites are native to California. They will sup on many harmful mites.
These predatory mites will happily devour Broad Mites. They like warm weather and will stop functioning if the temperature drops below 59°F.
Preferal can also be used against Broad Mites, Hemp Russet Mites and Eriophyid Mites. It can also help with Whitefly, Thrips, Aphids and Spider Mites. It’s made from a naturally-occurring fungus, Isaria fumosorosea, which is delivered via blastospores for fast germination. The spores stick to insects, then germinate and penetrate through their skin, continuing to grow inside. This kills the insect and more spores are released to do the same to other insects. Preferal won’t harm the good pests, or at least it’ll do very little damage.