Controlling spider mite pests in a cannabis crop is very important. While aphids and thrips can be relatively easy to treat for, the two-spotted spider mite, russet mite, and their kin can be extremely difficult to control. This is especially true once a colony is established. Further, if you don’t control for them then you will almost certainly catch a case. This is especially true in a living soil system since we don’t sterilize every piece of material (soil) before it comes into the grow.
When using the various sprays it is important to rotate the types of sprays you are using. If you continuously reapply the same type of spray, these hardy creatures can develop a resistance to it. Be cautious in living soil systems because many sprays will hurt your microbial populations as well. Although spider mites can develop a resistance to sprays, there is one thing that they can’t become resistant to: being eaten!
Predator mites come in all shapes and sizes. Fortunately, they are reasonably priced these days and are easy to purchase. I recommend applying predator mites just after your spray regime has ended. This is usually sometime around the second week of flower. I find that using these insects as a control measure, and not as a response to infestation, is most useful.
Select your predator mites based on your environment. Some predators like it warm and dry, others don’t mind it being cool and moist. Selecting the right variety for your environment will help them get established and ensure that they remain hungry! Also, if you have an active infection you will want to buy a bottle of hungry adult predators. Meanwhile, if it is purely preventative, you can purchase time-release sachets for extended protection.
I have had success with P.persimilus for active infections, and a knock-down spray will be needed [first] to help get the infection under control. A.andersoni, A.cucumeris, and A.swirskii are good beneficial to keep as they have a varied diet and may subsist on pollen and mold as well. This means that they will persist in the garden much longer as a preventative measure.
NOTE: A.cucumeris is a thrip predator and is not effective against spider mites.
I hope you have found this information useful. Exploring the world of beneficial insects can be challenging, but it can be fruitful as well. Stay tuned – in a future article I will detail how to create a breeding colony of beneficial predator mites.
Happy Harvests!
— The Lit Farmer —
