Not many people are happy to find a spider web in their home, but what happens when you see one on an indoor plant? You might be surprised these webs aren’t made by spiders but by a fellow arachnid called the spider mite.
So if you have a mite problem, several natural spider mite predators are happy to help you get rid of them.
There are approximately 1,200 species of spider mites in the Tetranychidae family. However, the best-known species is perhaps two-spotted spider mites (Tetranychus urticae), also known as the red spider mite).
These pests have zero interest in catching other problems, and they’re also one of the more devastating piercing bugs to infest plants.
The good news is you don’t have to resort to chemicals when faced with this tiny red menace, as predation is one of Mother Nature’s built-in defenses against any species becoming too crowded.
Spider Mites 101
Adult spider mites are tiny, measuring around .04″ inches long, and feed by piercing a plant and drinking its sap.
As with many arachnids, they can spin silken webbing, which they use to create bridges between parts of the plant (and sometimes nearby plants).
Adult spider mite females can lay up to 20 eggs per day, taking as little as three days to hatch under optimal conditions.
Once hatched, the resulting nymphs can become sexually mature in only 5 days and live for as long as 4 weeks.
As a result, it doesn’t take long for a massive population explosion to occur.
Even worse, spider mites have been known to use their silk to infest nearby plants, meaning there’s no such thing as an unexposed plant if it’s within several feet of an infected one.
There can be hundreds or even thousands of spider mites per plant, so while one is of little concern, a full colony can kill even a strong plant.
Their rapid reproductive rate also means they can quickly build up a resistance to pesticides, making natural remedies the best solution.
Natural Spider Mite Predators
The following natural predators prey on spider mites (and other pests) without harming the infested plant.
But before we get into the hunter, let’s review why the prey is such a big problem.
Known as a whirligig mite, this predatory mite species has become an essential ally in the battle to control spider mites and many other common pests.
Whether it’s a crop plant (especially apple trees) or an ornamental, introducing a bunch of these mites will immediately spread out among the leaves and even into nearby plants.
A single nymph or adult mite can consume as many as 100 preys per day.
They’re a cosmopolitan species (meaning they’re found worldwide), so they’ve quickly become a key biological control agent.
You might not want these guys in your potted plants, but they’re incredible allies for a garden, greenhouse, orchard.
This is another member of the Phytoseiidae family that’s well adapted for use with orchard and berry plants.
It has the curious habit of changing colors based on its prey and the plant.
It becomes blotchy green when feeding on Tetranychus urticae on cane berries, gold if eating Tetranychus urticae on strawberries, or red if eating the European red mite (Panonychus ulmi).
Unlike Phytoseiulus persimilis, they also have another advantage: they feed on other arthropods and pollen, allowing them to continue populating plants once the spider mites are eliminated.
A single female can lay between 1 and 5 eggs per day, resulting in as many as 60 during a lifespan ranging from 14 to 62 days long.
They don’t eat spider mites in the earliest stages of life, but by the time they reach adulthood, a single female mite can eat between 2 and 16 spider mites per day.
Of the Phytoseiidae family, one of the most beloved species is Phytoseiulus persimilis, which absolutely loves feasting on red spider mites.
One of these predatory mites can consume 5 adult spider mites or 20 eggs in a single day!
As they prefer a humidity of 60% percent or higher and warmer temperatures, P. persimilis commonly finds itself employed in greenhouses.
Using P. persimilis outside of a greenhouse may be a little more difficult to keep them going.
Temperature-wise, they’re active in temperatures from 55 to 105° degrees Fahrenheit and at their best in the 70° to 85° degrees Fahrenheit range.
50° degrees Fahrenheit is the minimum they can tolerate, with anything below that leading to death.
A single female lays only 2 to 3 eggs per day, up to around 54 eggs in her lifetime.
P. persimilis has an approximate lifespan of 30-36 days, meaning you can get a decent population with a little TLC.
However, when facing a large spider mite infestation or poor conditions, it may be necessary to reintroduce this predator every 7 to 10 days.
This genus of a ladybird beetle (family Coccinellidae) is another well-known predator of spider mites.
Two of the more famous species are Stethorus punctillum and Stethorus picipes (which have the nickname “spider mite destroyer” due to their efficiency).
Members of this genus can devour a staggering 75 adult spider mites per day, making them one of the most valuable allies in controlling spider mite populations.
While only living 1 to 2 months, a single female can lay 100 to 200 eggs in her lifetime, which she’ll lay one at a time throughout the spider mite colony.
Other Great Spider Mite Predators
Of course, the species we’ve covered are just the tip of the iceberg when dealing with this agricultural pest.
Several smaller insectivore birds will happily feed on spider mites, and both ladybugs and parasitic wasps are known to feast on these tiny terrors.
For spider mites, a garden that welcomes beneficial insects, birds, and other small creatures also have a high predation risk.
So before going out and investing in a chemical insecticide (or ten), try appealing to Mother Nature herself for an effective and efficient solution in the form of natural spider mite predators.