There are many types of mites, with over 48,000 species described so far. One of the more common species are spider mites (of which there are also many species).
Spider mites are tiny pests that can cause major problems for gardeners and indoor plant enthusiasts alike. In fact, these fast-reproducing arachnids are considered one of the most destructive plant pests around.
What are spider mites?
Today I want to delve into the world of spider mites. These pests may seem insignificant, but they are a formidable foe. Measuring less than one-twentieth of an inch, they are nearly invisible to the naked eye (with the period at the end of this sentence being double their size). However, don’t underestimate their ability to cause damage to your precious plants.
Spider mites, or Tetranychus urticae, belong to the Tetranychidae family, and they're closely related to ticks and spiders. Despite their scientific name, they're commonly referred to as "spider mites" (which is just slightly easier to say), due to their spider-like appearance. These pests are masters of disguise. With their tiny, translucent bodies, they expertly blend in with the leaves they infest, making them difficult to detect until it's often too late.
What do spider mites eat?
Spider mites feed on plant sap, as plant sap contains essential nutrients they need for their survival and reproduction. This sap is a rich source of sugars, amino acids and other compounds that are vital for the growth and egg-laying ability of spider mites. The water content of the sap also helps the spider mites survive in arid environments.
For outdoor plants, spider mites do not have any specific preference for plant types and will greedily feed on a wide range of plant species. However, some plant species are more susceptible to spider mite infestations than others. Spider mites are known to particularly favor plants with thin, delicate leaves such as fruit trees, strawberries, beans and some ornamentals like roses and azaleas.
In terms of indoor plants, some common houseplants that are more prone to spider mite infestations include spider plants, jade plants, English ivy and various types of palms.
Additionally, plants that are already stressed or weakened due to environmental factors like heat, drought or nutrient deficiencies may be more vulnerable to spider mite infestations.
But here, friend, is an interesting fact: spider mites use plants not just for food, but also as a shield from predators. You see, as these tiny pests suck on the sap of plants, they leave behind a residue of their saliva that hardens and forms a protective barrier, known as a webbing, around them. This webbing is not only a physical barrier that keeps predators at bay, but it also camouflages the spider mites, making them difficult to spot. And, as an added bonus, the webbing provides a humid microclimate for the spider mites to thrive in, even in dry conditions. It's a brilliant strategy, really, but a frustrating one for gardeners and indoor plant enthusiasts.
Do spider mites lay a lot of eggs?
Spider mites, like aphids, are prolific breeders. One of the most challenging aspects of dealing with spider mites, in fact, is their incredible reproductive ability. Female spider mites can lay hundreds of eggs over a two to four week period, and in optimal conditions, these eggs can hatch within just a few days. This rapid reproduction rate allows spider mite populations to explode in a very short amount of time, making it crucial to catch and treat an infestation as early as possible.
What damage do spider mites cause to my plants?
The damage caused by spider mites often starts small and can gradually get worse over time. As the mites use their specialized mouthparts (chelicerae) to pierce plant cells and feed on the sap inside, the stippling and discoloration of the leaves can become more severe, and the plant may begin to weaken and wilt. If left untreated, the infestation can spread to other parts of the plant or other plants in the area, leading to further damage and potential loss of the plant.
Here are four ways in which plants are damaged:
- Stippling: As spider mites feast on the sap of leaves, they cause the plant cells to lose their pigments, resulting in the formation of small, light-colored spots known as stippling.
- Discoloration: As the infestation worsens, the leaves may turn yellow, brown or even bronze in color.
- Wilting: Infested leaves may wilt or curl.
- Webbing: Spider mites may also produce fine webbing around the leaves and stems, which can block sunlight and inhibit photosynthesis.
How do I protect my plants and get rid of spider mites?
To protect your plants and get rid of spider mites, here are some steps you can take:
- Regularly inspect your plants: Check your plants for spider mites regularly, especially the underside of leaves where they tend to feed and lay eggs. Early detection is key to preventing a full-blown infestation. Note: Gnats and aphids will also take up residence on your plants.
- Increase humidity: Spider mites thrive in dry conditions, so increasing the humidity around your plants can help prevent infestations. You can use a humidifier or mist your plants regularly.
- Remove infested leaves: If you notice any leaves that are heavily infested, remove them immediately to prevent the spider mites from spreading.
- Introduce natural predators: Ladybugs and predatory mites are natural enemies of spider mites and can help control their population.
- Repel with specific plants: There are several plant species that can be effective in repelling insects, including spider mites, such as marigolds, chrysanthemums and garlic. Marigolds, in particular, contain compounds that are toxic to spider mites and they can be planted around other susceptible plants as a natural repellent. Chrysanthemums contain pyrethrins, which are commonly used in insecticides and can also repel spider mites. Garlic, when planted near susceptible plants, can deter spider mites with its strong odor.
- Use Dr. Killigan’s Dust to Dust Non-Toxic Insect Powder: Dust to Dust is a non-toxic, plant-safe powder that will rid your plants of spider mites. Its main ingredients include two essential oils—peppermint and rosemary—and silica. Peppermint is noted for its natural ability to repel many pests. A spider mite’s smell receptors pick up on and are repelled by the chemical compounds that make up peppermint oil. Rosemary oil contains several compounds which have insecticidal properties. These compounds interfere with the nervous system of spider mites, act as a respiratory and nervous system disruptor (to spider mites) and disrupt their pheromone communication system. Silica is not only essential for the growth and development of plants, but can also reduce pest populations, including those of mites, through creating an abrasive plant surface and stimulating the production of defensive compounds, such as lignin and phenols, to help to deter pests. It also helps reduce a pest’s growth rate. For plants, Dust to Dust is best applied as a wettable powder to (the plant’s) soil, leaves and stems. Not only will Dust to Dust deter spider mites and provide an effective and natural way to control them, but it will also help your plants grow healthy and strong.
