Predator mites are carnivores and like what the name sounds, are a type of mite that eats other mites. There are some main differences between the predator and its prey. Where spider mites are herbivores, feasting on your crops, predatory mites are strictly carnivorous and will only eat other bugs.


Unlike beneficial fungi or microbials which are little living organisms that are beneficial for your plants, mites are NOT a tiny organism you want in your grow room. The reason is that they actually feed on your plants and drain them of valuable nutrients and chlorophyll and can kill your plants! They are basically like “vampires” that will suck your plants dry and can ruin your entire harvest.


When cannabis growers hear the dreaded word “mite”, it sets off an image in their minds of this giant infestation of mites coming from seemingly nowhere and eating their crop to the stems. While they don’t start off quite that bad, it’s true that if not kept under control this very small-sized tormentor can turn into a very large problem rather quickly.
Predatory mite feasting on prey


Now all of this increased safety and compliance with strict regulation that comes with using predatory mites makes it effective as a pest control. Predator mites have been used in traditional farming for a long time and have proven especially useful for berry and grape farmers. Back in the 1980s, farmers were having issues with spider mites on strawberry farms because they had become resistant to many of the available chemical pesticides. Because of the potential for resistance, it was found that the predatory mites persimilis and fallacis, “can be more effective than chemicals.”


One of the reasons for the predator mites’ effectiveness, besides that spider mites don’t build a resistance to them, is that predators also eat the spider mite eggs. Many traditional and organic pesticides only attack the bugs that have hatched. According to Andrew Maltby, president of Biotactics, mites (both good and bad) breathe through tiny pores on their legs. Miticides and oil based pesticides, generally work by blocking the pores and basically suffocating the mites, yet they do nothing to the eggs. Generally, after applying traditional pesticides, two to three days later, all of the eggs from the first generation will hatch, and you will have a second wave of the infestation to deal with. This would mean you’d need to spray again.


Considering the increased regulations that legalized states are imposing, the answer isn’t getting any easier to deal with. Growers can no longer simply spray their crops with effective pesticides to lose these demon-like creatures. Sprays will likely not get past the pesticide tests. Increased regulations, concerns for safety and just plain effectiveness are going to be the driving forces behind this change.




How To Identify Mites on Infested Plants

Mites are closely related to ticks and even spiders. There are many types of mites and some more common than others.

Spider mitesSpider Mites – these tiny bugs (less than 1-mm long) are probably the most common (and most hated) of all indoor garden pests. They are actually little arachnids and because of their small size you may not notice them until they do serious damage to your plants.

There are two reliable ways to spot an infestation: one, look for spider-like webbing. Two, take a tissue and wipe gently on the underside of leaves–if it comes back with streaks of Spider Mite blood–you know you have mites.

Spider Mite predator:  Western mites, Amblyseius andersoni, Neoseiulus amblyseius, californicus & Amblyseius swirskii are among the effective predators against spider mites.
Purchase predators from a reputible dealer:  Hydro Gardens




Broad MitesBroad Mites – are so tiny they’re impossible to see with the naked eye, and still really difficult to see with a microscope. Broad mites reproduce prolifically between 70-80º F. They hatch in two-to-three days and each female can produce 40-50 eggs. Broad mites inject a toxic growth
hormone into the plant that slows and distorts growth. Look for leaves with the edges turned up as if your plant is suffering from heat stress–and your plant can even take on a glossy appearance that looks like fake plastic leaves. Eventually, these leaves will turn yellow or bronze then die.
Broad Mite predators: Amblyseius andersoni, Neoseiulus amblyseius, californicus & Amblyseius swirskii


Purchase predators from a reputible dealer: Green Methods



Hemp Russet MitesHemp Russet Mites – Lack of plant vigor, curled or taco-shaped leaves, yellowing and dropping of leaves. Hemp Russet Mites are the newest plague to hit cannabis growers. They cause severe damage and can spell disaster to any grow, from small to large. Many gardeners don’t even know they have them until it is too late.unlike spider mites, these leave no webbing. Visible damage to your plant, like the Broad Mite, is usually the first signs of an infestation. Unlike most varieties of mites, they only have two pair of legs. They start low on the plant then work their way up, so check slightly above wherever a plant is showing stress with a microscope that’s at least 14x power.

Hemp Russet predator:  Amblyseius Anderson

Purchase predators from a reputible dealer:   Green Methods




Cyclamen Mites
Cyclamen Mites – are very similar to broad mites. They’re less than 0.2 mm long and can be colorless to green or brownish. They have 8 legs. Male cyclamen mites have a very strong claw mounted at the end of each fourth leg. They avoid light and prefer high humidity and cool 60º F (15º C) temperatures. Like the spider mite, they feed on the cells of your plants by sucking it out with their mouths. Their feeding causes stunted growth with leaves generally curling upward. Leaves get stiffened and brittle and flowers are deformed or reduced.
Cyclamen Mite Predator:  Amblyseius andersoni and Amblyseius swirskii
Purchase predators from a reputible dealer: Hydro Gardens




Types of Predatory Mites
One of the first commercially produced biocontrol agents, back in the late 1960s, was Phytoseiulus persimilis, a predatory mite to control two spotted spider mite(TSSM). Since then several other species of predatory mites have been introduced to control a range of different pests: Amblyseius cucumeris, Amblyseius swirskii, Ambyseius californicus and many others.


The thing that all these species have in common — they are predatory mites, not insects. One significant difference between insect and mite biocontrol agents is that mites cannot fly, meaning success with predatory mites depends a lot on choosing the right introduction method.


Persimilis and californicus are some of the more common predatory mites, but there are several other types of mites that are released in different climates, species of pests and growing conditions. With this arsenal of mites at your disposal, you can fend off spider mites, thrips, broad mites, whiteflies, fungus gnats and more. These are equally effective if you’re growing indoors, outdoors or greenhouse. Predator mites really have your back and will help your grow pass state-mandated pesticide tests.


Mites are tiny, but you can usually spot them with the unaided eye. They may look like insects, but they actually belong to the same family as ticks and spiders. Many species of mites exist, several of which commonly affect humans. Different types of mites like specific kinds of environments.



Specifics About Predator Environmental Requirements


Mite Predator, Amblyseius andersoni – Survives on Mites, Thrips, pollen, honeydew and fungi making them great for both preventative and active control measure. 42-100°F, higher RH for higher temperatures
Mite Predator, Amblyseius swirskii – Rapid development and wide-ranging food sources are two of their main benefits. Commonly used for Mite, Thrips and Whitefly infestations. 60-85°F, 70% RH
Mite Predator, Neosiulus fallacis – Thrives in moderate to cool conditions with higher humidity levels; highly recommended in greenhouse settings. 55-80°F, 50%+ RH
Mite Predator, Neoseiulus californicus – Versatile and tolerant of a wider range of temperatures and lower humidity than P. Persimilis. 50-105°F, 40-80% RH
Thrips Predator, Amblyseius cucumeris – Great when used alongside Orius insidiosus and in greenhouse releases. 66-80°F, 65-72% RH



Predatory Mites Commercial Suggested Source

Anderline biological control agent contains the predatory mite, Amblyseius andersoni. It is a predatory mite that feeds on many types of small arthropod prey and pollen. It is ideal for preventive protection of greenhouse or outdoor ornamentals, vegetables and fruit crop

Amblyseius andersoni Key Features:
Predator of two-spotted spider mite, European red mites, broad mites, cyclamen mites and russet mites.  Will also feed on pollen and thrips larvae allowing the population to survive when pest mite populations decrease.  Since it is effective at lower temperatures, Amblyseius andersoni can be introduced much earlier in the growing season than other predatory mites.


Target Pests
Broad mite
Cyclamen mite
Two-spotted spider mite
Carmine mite
Tomato russet/rust mite
European red mite






Effective Release Methods of Predatory Mites

History of Release Methods of Predatory Mites

In 1989, a major change was developed that has impacted how many predatory mites are available today. It all started with a single stem flower flask (bottle), in the Netherlands known as ‘Anthurium flesjes.’ One cucumber grower filled some of the flasks with Amblyseius cucumeris and carrier material and placed them in the crop to release predatory mites every day. The results were incredible and many other cucumber growers followed this example. This was the “birth” of CRS sachets (Control Release System) and many growers started using this technique to introduce predatory mites.

How does it work? Amblyseius cucumeris (and several other Amblyseius species) are produced on bran mite species, hence the bran as a carrier. The typical ratio between predatory mite and bran (feeder) mite is 1:10. These sachets are literally an extension of the production that takes place at the biocontrol producers. The main advantage of using breeding sachets versus broadcasting is more than less frequent introductions. It has also been proven repeatedly that the use of breeding sachets gives more consistent and higher levels of predatory mites, which means higher success rates of using biological control.

Modifications for the Ornamental Industry

In the early 2000s, when biocontrol started to become more popular in the ornamental industry, it became clear the CRS system wasn’t suited to ornamental crops. The first development was the gemini sachet (2002), which is two sachets connected together so they can be hung over a mesh crop support wire (like a saddle on a horse) in cut flower production, primarily cut chrysanthemum. As this technique was still labor intensive, the next development was the bugline (2006), later followed by Certirol. This is a long roll of continuous sachets where only every third or sixth sachet is filled with mites; this is rolled out over the mesh crop support wire, saving labor and at the same time creating a ‘mite highway’ for better distribution of mites.

Over time, the concept of release sachets has continued to evolve, with the most recent development starting in Canada in 2014. Several ornamental and vegetable propagators were stapling sachets to plant labels or popsicle sticks to introduce the sachets even earlier in the production process. Timing of establishing predatory mites is “make or break” for success, so the earlier the better. The biocontrol industry responded by developing the sachet on a stick (2014). As these sachets are used in propagation (and outdoors), where overhead mist or water is a given fact, the sachets are produced with water-resistant paper and the exit hole is protected so water cannot get in. Once again, the uptake of this type of sachet was broader than expected, with many growers choosing to switch to the stick sachet because it is easier to place.

Do I Broadcast/Blow or Stick/Hang Predatory Mites?

Despite the invention and uptake of sachets, in some situations Amblyseius predatory mites are still applied by leaf blower to broadcast mitesbroadcasting or using modified leaf blowers. This is mostly done when it is thought that it is not cost effective to use a sachet.

If blowing, it is important to monitor the survival of the mites and the quality of the distribution, this can be done using a large white cardboard sheet. Gas powered blowers are known to have low survival rates. Another critical issue when broadcasting is using weekly applications, as there is very little reproduction happening in the crop.

Once taking losses and labor into account, many growers realize that blowing or broadcasting weekly at 10 mites per square foot often costs the same as using sachets. The key point is that, in general, breeding sachets have shown to result in more consistent and higher numbers of predatory mites, which means higher success rates of biocontrol programs.



While it may be counter-intuitive to put bugs on your plants in order to rid you of a different bug, it is safe and effective. If you want to survive in a world of regulated cannabis, predator mites are soon likely to become your new best friend in the constant war on spider mites. Even if you do not have to abide by testing standards, you should consider the health and safety benefits of predators, not only for yourself and your employees, but especially for your customers and your planet.


using drone to broadcast predatory mites broadcasting predatory mites




More ways to identify mites:

Grow Hack: Predatory Mites on the Attack!

Spider Mite

Know your enemy, Sun Tzu, The Art of War
“If you know the enemy and know yourself, you need not fear the result of a hundred battles. (2001)



Donna Ebeling About Donna Ebeling

Gardening had always been my passion, until I learned about organic gardening. That’s a whole new ballgame. So when I was asked to write for this blog, I jumped at the opportunity to research, to learn more about organic gardening and to write about that and other plant-related topics. Thank you for being here, I hope you enjoy these articles at least half as much as I do writing them!