Spider mites can cause considerable problems as pests in gardens.
Part of the Tetranychidae family spider mites is the most common pest in the garden. These mites are also some of the most common pests of indoor plants.
Spotting these bugs early is crucial when it comes to limiting the damage they do to plants.
You need to act soon before they kill plants as spider mites feed on the sap of various plants and flowers with rapid multiplication rates.
Spotting spider mites is difficult as these are small pests, similar in size to the head of a pin.
Table of Contents
What are spider mites?
Spider mites are a subgenus of Acari spiders. They have a small body that only grows up to a size of 1mm which makes them difficult to spot.
Spider mites feed on plant sap. As they feed, they impact plants turning their leaves yellow and even killing them.
This type of mites is called spider mites due to their capacity to wrap plants and flower buds in a silk web, similar to a spider web.
Spider mites wrap plants in webbing in case of serious infestations. This traps dust and prevents plants from growing naturally.
Spider mites can only be seen with a magnifying glass. They have a red, yellow, or green body that resembles the body of other mites.
These bugs have 6 legs as they are born developing into 8 legs as adults.
They have a sharp small mouth they use to pierce leaves and flower buds to drink the sugar-rich plant sap that helps them survive.
Types of spider mites
The following species are some of the most common spider mites you can come across in the garden.
1. Two-spotted Spider Mite
This species of spider mite (Tetranychus urticae) is mostly green, red or translucent green. Some of its morphs have 2 brown spots.
The mites are known for living all year long. The brown spots are visible from the outside (using a magnifying glass) only when the species has body waste.
This means young Two-spotted Spider Mites lack these visible spots.
Both young and adult Two-spotted Spider Mites can be identified by an elongated body with 12 pairs of setae.
2. Boxwood Mite
Boxwood mites (Eurytetranychus buxi) are a rare sight but they can cause faster damage in the garden compared to the Two—Spotted Spider mite.
Boxwood mites feed on both the upper and the lower part of plant leaves which kills plants faster.
Most other spider mites feed on the lower part of plant leaves.
You can identify plants infested by Boxwood Mites by the patterns of the bites on leaves.
Boxwood Mites leave in-line bite marks on leaves.
3. European Red Mite
These small European-origin mites (Panonychus ulmi) are now found across the US. They eat the leaves of peaches, apples, plums, and cherries among others.
European Red Mites have a dark red color and they grow to a size of 0.16mm.
The spider mites cause stippling on leaves. The leaves of fruit-bearing trees turn brown.
This is something many spider mites are known for and it’s referred to as bronzing.
4. Gorse Spider Mite
The Gorse Spider mites (Tetranychus lintearius) are native to Europe but found across the world.
It gets its name from eating the Common gorse, a weed in many countries.
The Gorse Spider mite is red and known to only affect one flower or plant it grows on.
It has specific parasitic behavior as it spends its life on a single plant.
Early Signs Of Spider Mites
Detecting spider mites early is key to preventing stunted plant growth or dying plants.
1. Yellow, tan, or white patches and holes on plant leaves
Colored patches on plant leaves are among the first warning signs of a possible spider mite invasion.
These patches have different colors depending on the species of spider mites affecting them.
Small colored patches on the leaves are often not taken seriously as many people think they’re normal.
It’s only when they also notice holes in leaves that people start to ask themselves about possible plant pests.
So how do these holes occur? It’s the sucking mouthparts of spider mites that are responsible for these holes.
They suck the sap of the leaves to a large or a small extent.
The more sap they suck from a certain spot the higher the discoloration or hole-formation chances are for that particular spot.
Spider mites can still hinder the plant even without the holes in the leaves.
Finding these early signs of spider mites is sometimes difficult.
Holes can be seen from above. You can see them affecting leaves even from above.
Yellow, tan, or white patches on leaves aren’t easily visible as they first occur on the underside of leaves.
You have to actively look for these marks which means you need to turn the leaves upside down to check for possible pest impact.
Only Boxwood mites affect the upper side of the leaves which means most other mite spots on leaves aren’t visible if you don’t turn the leaves over.
Spots or patches on the leaves are a bad sign but it can be one of the few occasions to save a plant if you act quickly.
So what do these spots look like? Apart from their white or tan color, you can identify these spots by their size.
Most spots only become visible as they grow over 1mm. You can see a small cluster of spots that appear as a large spot contrasting the green color of the leaves to confirm an invasion.
These spots are rarely confused with the eggs of spider mites which are white and smaller.
Clusters of spots are typically seen on multiple leaves, it’s worth checking all plant leaves to confirm the presence of spider mites.
2. Yellowing leaves
Spots on leaves eventually lead to yellowing leaves. This is a sign that the green leaf has started to die or that it has died already.
Yellowing leaves are a bad sign for plant growth.
The appearance of these leaves might signal that a given plant is about to stop growing.
It’s best to check for one yellowing leaf early on as seeing multiple yellowing leaves on a plant might be already too late.
You can remove the single yellow leave from the plant and check for other spider mites on the rest of the plant.
How do plant leaves get yellow due to spider mites? Multiple bites on leaves create multiple spots.
Whenever there are too many spots on a leaf the leaf will turn yellow and die.
While most spider bites bite the underside of leaves, the yellowing reaction is common to all areas of the leaf.
3. Brown curled leaves
Brown leaves are also common on plants affected by spider mites.
This is an extreme reaction to the bites of spider mites.
Brown leaves curl immediately. They curl at the edges first but the edges of a brown leaf can even meet in an extreme upward curling movement.
Brown leaves are almost always confused with a sign of drought.
People mistakenly start watering the plant more and more thinking it lacks sufficient water.
What does a brown leaf look like? It’s a uniform brown leaf that lacks texture and the natural green color it normally has.
It feels dry when touched, almost too fragile by comparison with a hydrated green healthy leaf.
4. Early drop or premature wilting of leaves
Losing plant turgidity is known as wilting. Whenever you see wilted leaves or a plant that wilts too soon it might be a sign of a spider mite problem.
A loss of turgidity is attributed to a loss of water or sap in leaves.
This is where the leaves will drop all of a sudden and it might be a good idea to check all leaves for a possible spider mite problem.
As soon as the leaves start to drop it’s a clear indication they won’t come back up again.
Wilting leaves are unfortunately not considered a sign of a spider mite problem for many people.
Many people believe the plant isn’t getting sufficient water whenever the leaves start to wilt and start to water the plant more.
5. White, cottony web on the stems and leaves
Spider mites are known for building cotton web weaves on leaves. This is characteristic of these bugs often confused with spiders.
The spider webs have a white color, similar to traditional spider webs.
It’s only with serious pest invasions that these web weaves appear. They aren’t visible in the first week after spider mites arise.
Spider mites affect a plant a long time before you can see their spider webs. They can drink the sap of leaves well before they install their spider webs.
These spider webs are made for protective purposes. Spider mites use them to keep potential predators away.
Spider mite web vs spider web – what are the differences?
There are considerable differences between the purpose of a spider mite web and a regular spider web. These look different as well.
One of the little-known benefits of the spider mite web is that it helps these spider-like creatures travel with the wind.
Spider mites are small and lightweight but a small spider web their ride on helps them drift with the wind easier and over longer distances.
The webs spider mites travel on are typically small and may not be visible to the naked eye.
The main reason spider mites build spider webs is to protect themselves from predators. They encircle an entire leaf, multiple leaves, or flower buds they feed on.
However, spider mites close not only themselves but also their family members and other spider mites in the spider web as these aren’t solitary creatures such as most true spiders.
- Keeping dust out
Dust settles on plant leaves and it may prevent spider mites from easily drinking plant sap. However, the spider mite web they build around plant leaves keeps dust particles out.
Some of the older spider mite webs look very dirty. This is the result of the dust that settles with the wind.
- Not catching insects
A common misconception about the spider mite web is that it’s built to catch insects. This isn’t the case.
Only spiders build spider webs to catch insects. Spider mites are not carnivorous.
Seeing spider mite webbing on a plant is one of the signs these pests aren’t planning to go away and that they like a certain plant.
These spider mite webs can be seen anywhere on the plant, but rarely on the plant stem in favor of plant leaves and buds.
Spider mite webs can be removed by hand easily. Wind rarely removes them.
6. Live spider mites, spider mite’s egg, and poop on the plants
A clear early sign of a spider mites is seeing one or multiple live spider mites.
Seeing their eggs is a clear indication adult spider mites will soon arise as well.
Spider mites are quite difficult to see in their full shape and color due to their reduced 1mm size.
You can identify these mites as small dots that move.
The moving speed is slow, but you can use a piece of white paper to shake off these mites and see them moving.
Spider mites have an orange color, a red color, or a green color.
Upon close inspection under a magnifying glass, you will also see this color is translucent.
Spider mites can also be brown. It’s believed this color is rare.
Spider mite coloring is affected by the time of the season.
Seasonal changes dictate the change of color. As the leaves are naturally yellow towards the beginning of the fall spider mites start to look darker in color as well.
What do spider mite eggs look like?
Spider mite eggs look like tiny translucent eggs. These tiny eggs turn off-white, cream, or tan just before hatching.
Seeing spider mite eggs on a plant is a clear indication of a pest problem.
Adults have already started feeding on plant leaves when you see these eggs on the plant.
However, adults are typically just nearby these eggs, often on the same plant.
Adult spider mites might also build large spider mite webs around leaves and eggs.
Apart from offering protection, these spider webs also offer a type of physical surface for the newly-hatched spider mites to crawl on while moving from one leaf to another.
What does spider mite poop look like?
Spider mite poop is another early indicator of a possible plant and garden invasion.
This poop comes in different colors.
Most spider mite poops are black. Brown and even white spider mite poop can also be seen on plants.
Spider mite poop can have a round shape but it can also have a splash shape.
7. Touching the leaves feels like they’re covered with “fine sand”
The texture of the leaves might give away potential spider mites.
Not visible when they’re only present in small numbers, spider mites can be palpable or distinguishable by touch.
You can rub a leaf with your fingers to discover a sand-like texture. This texture is the spider mites you are feeling with your fingers.
Spider mites don’t bite so this technique can be used on plants and leaves you want to check spider mites on.
8. Ladybug activity around the plants
Ladybugs are natural predators of spider mites. These tiny bugs are eaten by ladybugs and by aphids.
Natural predators such as ladybugs can be an early sign your garden and the plants in it are housing spider mites.
Ladybugs are predatory and only feed on small bugs on crops.
As a result, a high activity of ladybugs in your garden is an indication of spider mites on leaves.
Ladybugs don’t stay around for long whenever they cannot find food.
9. Another spider-mite infested plant nearby
If you already have spider mites on one plant you can expect these bugs to move on to another plant as well.
Most spider mites prefer to sit on one plant. This changes with overcrowding when they start to look for another host plant.
An early sign of a possible garden invasion involves adding your infested plant to a quarantine area.
This is an enclosed area spider mites cannot escape from to infest the rest of the garden.
Adding a plant mesh screen on top of the infested plant ensures these mites don’t easily spread through the garden.
How Do Spider Mites Spread?
Spider mites seem to appear out of nowhere in the garden. There are many ways in which the tiny arachnids make it onto plants as follows.
- Spider mites spread from other infested mites
The easiest way for spider mites to spread is by expanding their territory from other plants.
These 8-legged arachnids move on to another nearby plant whenever their current plant is dead or when it’s overpopulated.
Nearby plants are the best places for adult spider mites to lay eggs on as well.
- Animals carry spider mites
Animals moving around the garden can also spread spider mites. Cats and dogs are known for carrying spider mites that reach other plants and flowers.
- The wind carries spider mites
The wind is an important factor in the spread of spider mites. Since these arachnids are so small, they are easily blown away by high winds.
Spider mites have adapted to the high wind to the extent that they use it to move around to find new plants and new food sources.
How does a plant get infested by spider mites?
A plant can be infested by spider mites through no fault of its own. Even plants you’ve sprayed insecticide on can be a landing spot for wind-blown spider mites.
A plant first gets infested by a female that can lay up to 300 eggs at a time. During this time, the female starts to eat the leaves of the plant.
Other males and females can soon follow.
A single female can be joined by emerging spider mites within 5 days as it takes less than a week for spider mite eggs to hatch.
It can take as little as a week for spider mites to kill a plant. The more plant leaves are affected the shorter the survival time of the plant becomes.
When do spider mites affect other leaves?
Spider mites can spread to other leaves even when there’s sufficient plant sap on the leaf they live on.
The spread has been impacted by the overcrowding of plant leaves, a process that can take as little as a few days.
When do spider mites spread to other plants in the garden?
Spider mites spread to other plants in the garden whenever the current plant they live on starts to die.
Low amounts of leaf sap prompt spider mites to move on to another plant.
Spider mites can also move on to another plant whenever they have to compete for plant sap with too many other spider mites.
Spider Mite Damage
Damages inflicted by spider mites can be worrying for a gardener or a plant grower. These mites can cause serious damages which can kill off a plant in the worst invasions.
What damage spider mites can cause?
Spider mite damages largely depend on the number of these mites on a plant.
Few spider mites eating plant leaves have a different impact than thousands of spider mites eating a plant.
- Minor damages
Small damages are seen when there are just a few spider mites on a plant.
These cases have no impact on the plant which can often regenerate.
A few leaves might be lost in the process even if some plants survive this small impact without losing any leaves.
- Average damages
A medium-sized invasion of up to a few hundred spider mites can lead to stunted plant growth.
Leaves are lost all the time in this case, as are flower buds.
Plants might never fully recover with hundreds of spider mites eating them.
- Extreme damages
Thousands of spider mites kill a single plant in a matter of days.
Large invasions are hard to manage and even if you remove all of these mites the plant might not survive the heavy impact.
Why should spider mites be treated quickly?
Spider mites can be a minor or a major garden pest. They spread easily if left unattended quickly becoming a large problem for your plants.
The biggest reason to quickly treat spider mites is to keep plants healthy.
The healthiest plants are also those that grow the largest.
Even if spider mites don’t kill your plants that might still hinder their growth.
Spider mites on plants can also lead to an infested garden where multiple plants can suffer.
Can spider mites live on humans?
Spider mites exclusively feed on plant sap. They cannot survive on people.
People can help spread spider mites but they cannot be a host for them.
Spider mites can only survive a few days up to a couple of weeks without food. They will die on any other surface apart from plants.
Can spider mites bite humans?
Spider mites cannot bite people similarly to spiders. They can pierce the surface level of the skin with their sharp mouthparts.
These attempts largely go unnoticed as spider mites are very small creatures people don’t feel on the skin.
Can spider mites live in the soil?
Spider mites cannot live in the soil during the summer in their active months.
They only live in the ground in the winter when they enter a dormant state.
Spider mites die when they fall on the ground with no plants to feed on.
Do spider mites die in cold weather?
Spider mites enter a dormant state in the winter where they remain inactive and when they don’t feed at all.
This dormant state is typical of the cold months soon after plants die. They start to emerge again in the spring, which is also the season many gardens are treated against these bugs.
How To Get Rid Of Spider Mites?
Once you’ve identified spider mites on one or multiple plants in your garden you can proceed to eliminate them.
There are multiple solutions against spider mites which are sometimes combined for immediate results.
1. Water the plants with a strong sprayer
Watering the plants with a powerful sprayer or a good hose is recommended to clear spider mites.
A powerful hose can also eliminate spider mite webbing. At the same time, you want to limit the pressure of the water not to kill the plant in the effort of saving it.
Gradually increasing water pressure is recommended when it comes to clearing spider mites with a garden hose.
Water the plants with a mixture of alcohol and water
A mix of 30% alcohol and 70% water is often used to kill spider mites and their eggs.
All types of alcohol are used with this method.
Increasing the alcohol percentage further isn’t recommended. Too much alcohol can kill plants.
2. Spray insecticidal soaps
Insecticidal soap is a type of insecticide you spray on plants. This is a powerful chemical that is used to kill spider mites and other bugs as well as to prevent them.,
Using too much insecticide can be detrimental to crops such as tomatoes but it might be the last resort in the case of a serious invasion.
3. Buy ladybugs
Ladybugs are the most common natural predators of spider mites. You can buy thousands of ladybugs and release them in your garden as a natural solution against spider mites.
Ladybugs aren’t guaranteed to land on the plants affected by spider mites.
This is why the use of ladybugs is mostly recommended when growing plants on a commercial scale.
How to Prevent Spider Mites?
Preventing spider mites is the best solution to keep your plants healthy. All efforts should be concentrated in the spring period, the time of the year these bugs first appear.
1. Spray plants with neem oil
Neem oil is the natural alternative to insecticide. Mixed with water, neem oil is sprayed on plants at the beginning of the season and a few times through the summer to keep spider mites away.
Spraying neem oil more frequently is recommended in dry periods.
Spider mites like dry months and are likely to mate in higher numbers in warm weather.
2. Wipe plant leaves in the spring
Wiping plant leaves is also recommended in the summer to keep spider mites away.
Expensive plants that need special care are among those that are mostly recommended for wiping.
Each leaf needs to be wiped individually as spider mites can quickly spread from one leaf to the entire plant.
3. Spray hot pepper extract
Powdered hot pepper such as jalapenos mixed with water is a proven method of reducing spider mites.
Studies show that almost half of the spider mites living on a plant die on the spot when you spray hot pepper on them.
Multiday application is recommended to kill all spider mites when applying hot pepper extract.
4. Spray miticide
Miticide is a type of chemical used against mites such as spider mites.
You can find miticide in pest control stores. Alternatively, you may find this chemical as Acaricide.
Miticide is also used to prevent fungal plant infections.
5. Water the plants
Frequently watering the plants is recommended against spider mites.
These small pests are known for preferring dry days to mate and to eat.
High humidity is known to deter spider mites.
Increasing plant watering frequency during the hot and dry summer days is recommended to keep spider mites away.
Spider mites thrive in dry hot conditions where they invade plants in the garden.
These mites hatch in 2-3 days when the weather is warmer than 80 degrees.
Once they hatch they start feeding on plant sap. Spider mites reach sexual maturity within 5 days when they start laying eggs. Some of the most common plants affected by spider mites include strawberries, tomatoes, cannabis, and corn.