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Soil mites are essential mesofauna that shreds decaying organic matter and feed on dead bacteria, making essential plant nutrients bioavailable. There are thousands of soil mite species, and their local abundance is a soil health indicator.
About Soil Mites
Soil mites abound in almost every soil type, from your garden to tropical rainforests, temperate forests, and grasslands to bogs, caves, and salt marshes. Their extreme diversity is evidence of their specialization, reproductive abilities, and adaptability.
What is known is that acarid arachnids (mites) consist of tens of thousands of species, many of which are disease vectors. This is unfortunate because the four soil-borne soil mite classes do no harm and are, in fact, irreplaceably significant to soil and plant health.
How Small are Soil Mites?
Soil organisms can be divided into groups depending on their size, function, or ancestry. If we look at soil organisms’ sizes, three groups apply. Micro, meso, macro; small, medium, large. Meso biota is bigger than microorganisms but smaller than ants (macrobiota). Soil mites are tiny organisms with diameters ranging from four-hundredth to an eightieth of an inch (0.1mm to 2mm).
Why are Soil Mites Important?
The value of soil mites to soil health cannot be overstated. They are responsible for the aggregate formation, essential to saturation porosity (a soil’s ability to retain air when saturated), pathogen control, and nutrient recycling.
Healthy soils teem with micro- and macroscopic creatures collaborating to produce and sustain a vibrant, mutually beneficial ecosystem for plants. They aid in the natural decomposition of organic matter, breaking down decaying organic debris and converting it into energy and nutrients for plants and other species that rely on the soil.
Soil mites also ingest dead bacteria, fungi, and dangerous soil-dwelling animals, which are then excreted as nutrient-rich excretions back into the soil. Soil mites protect plants from fungal disease and insect infestations by devouring potentially harmful pathogens and pests.
Soil Mites and Soil Functions
|Maintenance of soil structure||The combined efforts of invertebrates, arthropods, and other soil organisms|
|Decomposition of organic matter||Various saprophytic and litter-feeding invertebrates (detritivores), fungi, bacteria, actinomycetes and other micro-organisms|
|Water (and air) regulation||Most invertebrates, some mesofauna, and the soil engineers, macrofauna.|
|Carbon sequestration||Mostly micro- and mesofauna and plant roots|
|Soil detoxification||Mostly micro-organisms, made possible by soil mites that break them down|
|Nutrient cycling||Mostly micro-organisms, but access to these nutrients in enabled by soil mites|
|Suppression of pests, parasites and diseases||The chief nematode and fungi predator is the Mesostigmatid soil mite. Some bacteria and fungi are also involved in suppressing pathogens. An increased soil biota diversity improves soil health and plant resilience.|
|Symbiotic and asymbiotic relationships with plants and their roots||Rhizobia, mycorrhizae, actinomycetes, diazotrophic bacteria and various other rhizosphere micro-organisms, soil mires and ants|
|Plant growth control||Most soil biota|
Tiny Bugs in Household Soil
Your household soil is less likely to have the common pests found in a garden, but this does not mean some critters won’t make it indoors. They could also enter your potting soil if the houseplants are occasionally left outdoors.
The most common soil-borne bugs or worms are earthworms, wireworms, pot worms, or the larvae or eggs of other pests. Indoor plant pests include aphids, thrips, spider mites, scale insects, mealybugs, Sciaridae, or whiteflies, but none of these are soil specific.
If the tiny bugs in your pots look more like bugs than larvae, and they’re really small, then it is most likely they are soil mites. These are tiny and almost imperceptible to the naked human eye (0.1 to 1mm).
If you want to find out more about worms in your soil, check out The Shocking Truth About White Worms in the Soil and How to Get Rid of Them
Types of Soil Mites
The Arachnida subclass, Acari, includes all mites and ticks. The subclass is divided into two superorders, each with several orders and suborders.
Four soil mite orders or suborders represent tens of thousands of soil mite species. Oribatid mites are the most ubiquitous, followed by Mesostigmata, the predatory soil mite order. Prostigmata and Astigmata are lesser suborders.
Beetle Soil Mites – Oribatid Mites
The most common soil mites are the Oribatei, often called beetle or turtle mites for their shell-like bodies. They consist of about 146 families and 8,500 species. Oribatid mites don’t grow more than a four-hundredth of an inch (1 mm) long, so you may require a microscope to see their body details (shell, four pairs of legs, and claws).
In intensive agriculture, their numbers are lower, but extensively managed grasslands can have as many as 150 different species per square meter.
White Soil Mites
As Look out for the following characteristic in these oribatid mites.
- White soil mites are usually white or light brown. Red soil mites, as we’ll see later, are generally predatory. Other colors include orange, black, yellow, pink, or green.
- Tiny at 0.01 – 0.06 inches (0.1 – 2 mm) long. Seeing a soil mite with the naked eye is challenging, but a magnifying glass will help.
- Not an insect but an arachnid (a close relative of ticks, but also spiders and scorpions)
- Soil mite nymphs have three pairs of legs (6), and adults have four pairs (like all arachnids).
- They might be seen walking on the soil’s surface but spend most of their time below it.
- Soil mites migrate, hitching a ride on beetles or other insects.
- Soil mites do not climb onto plants (if you see what looks like mites on the leaves, you could have spider mites or aphids)
- Generally, they are not apparent as they live in the soil but occasionally venture to the soil surface.
- Soil mites can’t fly or jump. Most are slow-moving or sedentary. If you have a little creature that jumps, it’s probably a springtail.
- Soil mites prefer moist compost and shady or darker soil areas with little direct sunlight.
- Soil mites are beneficial insects – it’s best not to try to get rid of or harm them.
- The red two-spotted spider mite is not a soil mite (and is seldom red).
Predator Soil Mites – Mesostigmatid Mites
The Mesostigmata are mostly predators feeding on other microorganisms like nematodes. A study on dwarf tomatoes to determine whether adding mesostigmatid mites can help control plant-parasitic nematodes showed a significant decline in galls.
The study shows the importance of mesostigmatid soil mites in keeping parasitic nematodes under control, a significant pest for most gardeners. The mesostigmatid soil mites are hugely beneficial in balancing soil biota populations. There are about 75 mesostigmatid soil mite families and 5,050 species.
Mesostigmatid mites are essential predators of nematodes, springtails, insect larvae, and the occasional spider mite and are often used as bioindicators. Soil mites can relocate rapidly using phoresy, hitching a ride on beetles.
Intensive farming and the use of pesticides negatively impact soil biota diversities and, by implication, soil health.
Astigmatid Soil Mites
Ever wondered what the tiniest white dots are in your nitrogen-rich soil? Astigmatid mites are white to tan and are soft-bodied soil mites. They are tiny, about six-thousandth of an inch to an eighth-hundredth of an inch (0.15 to 2.00 mm) long.
Unlike their oribatid ancestors, mostly restricted to the soil, the Astigmatid mites can be found in other habitats. Astigmatid soil mites are the least common group. Their populations in gardening soils only increase when debris levels increase after harvesting, after nitrogen applications or after rich manure applications.
Most soil-borne Astigmatid mites are microbe feeders.
Red Soil Mites – Prostigmatid Soil Mites
Prostigmatid mites can be terrestrial or aquatic and are predaceous or fungivores, an omnivore that boosts soil health. There are about 14,000 species grouped into 135 Prostigmata families.
Red Velvet Mite
Red velvet or patio mites (Trombidiid mites) spend most of the year below ground or under cover of soil debris as predatory soil mites. In spring, adults emerge and may be seen scurrying around on patios or walls.
Red Velvet mites venture above ground as they seek insects and insect eggs to feed on. Red velvet mites lay their eggs from early spring to mid-summer that hatch in mid-fall.
Differences Between Red Soil Mites and Red Two-Spotted Spider Mites
|Red Soil Mite||Red Spider Mite|
|Generally red||Generally light orange|
|Will move around alone||Always in a cluster|
|No spider webs||Spider weds|
|Feeds in nematodes, fungus gnat larvae, springtails and smaller soil mites||Feeds on the underside of plant leaves.|
Why do People Dislike Mites?
Humans are generally afraid of what they don’t understand. This fear of the unknown is common to all species, a caution developed over millennia that has allowed us to survive. Hello survivor.
Mites That Can Harm Humans (NOT SOIL MITES)
Some non-soil mites may bite and annoy people. These mites live outdoors on plants, but most feed on rodents and birds. Others may infest stored food, especially grains and cheeses.
Just to clarify, there are no such things as paper mites. Airborne irritants like insulation and dust often cause indoor rashes. Any bites are generally because birds have nested nearby (eaves, attics, and other places) or there is a nearby rodent problem.
- Hematophagous Mites – Hosted by Birds and Rodent
- Scabies Mite. Check out CDC for a recommended prescription for treating scabies
- Food Mites
- Harvest Mites (Chiggers)
- Straw Mites
- Oak Leaf gall Mites
- Dust Mites – Dust mites don’t cause itchiness but can aggravate allergies..
Managing Soil Mites
Soil mites are essential to the soil ecosystem, as they help decompose organic matter and cycle nutrients. However, in certain situations, soil mites can become pests and cause damage to plants, especially in a greenhouse or indoor growing environment. Chemical control of soil mites may be necessary in such cases.
Why do I Have Soil Mites?
Nature is designed to recover and reuse limited resources. Organic material is the product of dead plants and animals, filled with minerals and compounds nature needs for future growth.
The recovery of these resources is the work of the soil food web, a food chain with interlinking tiers of micro-, meso-, and macrofauna, feeding some birds and animals and making resources available for plant growth, the ultimate sun energy harvesters.
The microbiota consists mainly of fungi, bacteria, protozoa, and actinomyces. The mesobiota consists primarily of arthropods, specifically soil mites and springtails.
Working our way up the soil food web, the soil engineers, population controllers, and plant litter transformers are anthropods and earthworms.
Arthropod species form a significant part of the soil’s meso- and macrofauna. The primary soil-borne larger arthropods include
- Isopoda – woodlouse, sowbug, roly-poly, pill bugs
- Myriapoda – millipedes, centipedes
- Insecta – insect larvae, ants, beetles, and other insects
It is natural (and beneficial) for soil to have all of these, though the macroorganisms are less welcome indoors. This has an implication for the numbers of lower-tiered organisms as their natural predators are removed.
This allows them to abound, causing springtails and soil mites to get so numerous that they become visible. Without interference, other higher-tiered organisms would eat them in nature.
Preventing Soil Mites in Indoor Plants
Soil mites perform many essential functions in the soil community, such as soil aeration, preparing the organic matter for decomposition by microorganisms, and converting nutrients into forms available to plants.
Preventing them from doing this would require killing the soil or growing plants in inert materials like pumice, perlite, chickpea, or lightweight expanded clay aggregate (LECA).
Of course, we know this is possible in hydroponic systems, but do you really want to grow your houseplants in sterile soil?
Getting Rid of Soil Mites NaturaIly
Soil mite population diversity and numbers depend on an environment that supports their growth and health. There is a strong correlation between soil health and soil mite population size and diversity, a reason why soil mites are used as soil health indicators.
Falling Soil Mite Populations
Several conditions cause soil mite populations to drop. If, as we know, the abundance of organic material bodes well for soil biota, then its absence would cause populations to drop. One of the greatest threats to biodiversity is industrialized farming.
Industrial farming aims to produce large quantities of food at low cost, and it is widely used in the production of crops such as corn, soybeans, and wheat, as well as in raising livestock such as chickens, pigs, and cows.
Why Caution is Required in Controlling Soil Mites
Soil mites are often hailed as the primary shredders of organic matter, promoting soil creation and the transfer of nutrients and energy to higher trophic levels.
Different mite-feeding classes contribute differently to these processes. Fungivores and herbivore grazers significantly aid the decomposition of organic materials.
Grazer soil mites (oribatid mites) can break down resistant cell wall material, making their nutrients more broadly available for further processing. Predaceous and other soil mites grou[ed either by size, function, or taxonomical classification, contribute to healthy soil development as builders, pest controllers, or soil engineers.
The fungivore and herbofungivore grazers are typically responsible for the fragmentation of organic matter and producing nutritious excrement (like vermicompost). Soil mites increase aggregate soil stability through feeding activity.
Non-Pesticide Chemical Alternatives to Controlling Soil Mites
Hydrogen peroxide is a gardener’s best friend, helping fight root rot, plant pathogens, fungus gnats, and mites (named for their diet, not their species).
Hydrogen peroxide is a very effective therapy for all types of soil-borne pests. Without harming your plants, it will instantly destroy many adult bugs, nymphs, and eggs.
Hydrogen peroxide is available in a range of concentration strengths. What you need is a 3% concentration of hydrogen peroxide. If you have a stronger concentration, dilute it to 3%.
Horticultural oil is a type of pesticide that is derived from petroleum and is used to control insect pests and certain plant diseases. It is a highly refined oil specially formulated for use on plants, and it works by suffocating insects and mites by coating them with a thin layer of oil, disrupting their ability to breathe.
Horticultural oil is commonly used in organic and low-toxicity pest management programs because it is a relatively safe and effective alternative to synthetic pesticides. It is also relatively easy to use and has a low environmental impact.
Some of the benefits of horticultural oil as a pesticide include the following:
- Versatility: Horticultural oil can be used on various plants and crops, including fruits, vegetables, ornamentals, and trees.
- Low toxicity: Horticultural oil has low toxicity to humans and other mammals, and it breaks down quickly in the environment.
- Residual effect: Horticultural oil can leave a residue on plants, providing ongoing protection against pests.
- Resistance management: Because horticultural oil works by suffocating pests, it does not pose the same risks of pest resistance as traditional pesticides.
- Mode of action: Horticultural oil works physically rather than chemically, making it an effective tool for managing pests in an integrated pest management program.
However, it is important to note that horticultural oil has limitations and potential drawbacks. It can cause phytotoxicity or leaf burn if misused or at the wrong time, and it may not be effective against all pests or diseases.
In addition, horticultural oil should not be used during high heat or humidity, as it can cause plant damage.
Overall, horticultural oil can be an effective tool for managing pests safely and environmentally friendly, but it should be used carefully and following label instructions.
Insecticidal soap is a pesticide that controls a wide range of insect pests, including soil mites. It disrupts insects’ cell membranes, causing them to dehydrate and die.
Insecticidal soap is typically made from potassium salts of fatty acids and is considered a low-toxicity pesticide safe for humans, pets, and beneficial insects.
To use insecticidal soap to control soil mites, it is essential first to identify the type of mite present, as not all species of mites are susceptible to this treatment. Once the mite has been identified, the insecticidal soap should be mixed with water according to the label instructions and applied to the soil surface and foliage of the affected plants.
When applying insecticidal soap, it is essential to follow the label instructions carefully, as overuse or improper application can cause damage to plants.
It is also important to note that insecticidal soap is only effective against the pests that come into direct contact with it, so it may need to be applied multiple times over the course of several weeks to ensure complete control.
Questionable Soil Mite Control Recommendations
Gardeners try various tricks to control garden pests, from using urine to planting onions as companion plants. While some of these ideas work, they can have unexpected side effects.
Sticking to your local Extension office’s advice is better than drenching your soil with cinnamon or garlic solutions.
Chemical Options for Controlling Soil Mites
Before using any pesticide, it is essential to identify the specific type of mite present and to carefully read and follow the label instructions for the selected pesticide. It is also essential to consider the potential impacts of the pesticide on non-target organisms, such as beneficial insects and soil microorganisms.
There are several chemical options for controlling soil mites, including:
- Acaricides: These are chemicals specifically designed to control mites. They are available in different forms, such as sprays, powders or granules. Examples of acaricides include abamectin, bifenthrin, and cyfluthrin.
- Insecticides: Some insecticides can also be effective against soil mites. They work by disrupting the nervous system of the mites. Examples of insecticides include imidacloprid, permethrin, and pyrethrin.
- Fungicides: Certain fungicides can also help control soil mites by reducing their food sources. For example, dazomet is a fungicide that can also control soil mites.
It’s important to note that chemical control of soil mites should only be used as a last resort after other non-chemical methods have been tried and found ineffective.
Additionally, these chemicals should be used carefully, following all label instructions and safety precautions, to prevent harm to humans, animals, and the environment.
How Overwatering Affects Beneficial Soil Mites
Your soil biota is adaptable to excessive watering, but your plants aren’t. Because water is heavier than air, protracted overwatering expels all the air trapped in healthy soil and causes plants to drown.
What happens is that latent soil fungi (Rhizoctonia, Phytophthora, Pythium, and Thielaviopsis) flourish in anaerobic environments, causing root and basal stem rots.
Your greatest allies in preserving soil saturation porosity, a soil’s ability to trap air even when saturated, are soil mites. In their soil activities, which we’ll review later, they create microscopic tunnels, binding soil particles together to form aggregates. These tunnels trap air, allowing plants to breathe even when the soil is saturated.
FAQs about Soil Mites
Soil mites are essential to healthy soil and resilient, healthy plants. While there are mites that are pests, soil mites are not.