How to Spot and Get Rid of Spider Mites in Your Garden Plants
What are Spider Mites?
- 1 What are Spider Mites?
- 2 Signs of Spider Mite Activity
- 3 How to Deal with a Spider Mite Infestation
- 4 Spider Mites Don’t Have to Be a Death Sentence
- 5 Behavior and habits of spider mites
- 6 Identifying Spider Mites
- 7 Popular Plant Hosts
- 8 About the Author
- 9 Spider Mite Overview
- 10 Frequently Asked Questions
Spider mites aren’t actual spiders, though they are related. They’re so named because they look a great deal like the multi-legged creepy crawlies.
These tiny mites are bad news for your garden plants. When the weather warms, the mites creep out of the ground and start feasting.
Unlike other types of mites, they won’t harm you or your pets, but they can do a lot of plant damage, despite their miniature size. They use their mouths, which have needle-like appendages, to extract and eat the fluid of your plants.
Spider mites target a slew of plants, so there’s a chance you’ve had to deal with them at one point or another. Haven’t spotted spider mites on any of your plant babies? It’s bound to happen at some point!
Hydroponic systems, even those indoors, are especially prone to spider mite infestations.
Signs of Spider Mite ActivitySpotting these little buggers is a bit tough. They’re hard to see with the naked eye. If you look carefully, though, it’s possible to see them moving along plant foliage.
Since they’re so hard to spot, the best way to check for spider mite activity is to look for their distinct webbing and plant damage.
If you notice plant foliage has small holes, and there’s webbing nearby, you likely have a spider mite infestation on your hands. The presence of webbing, however, usually means you’ve caught the infestation late in the game.
If it’s apparent that a plant is infested, you’ll need to act quickly to salvage the situation.
Anytime you notice your plants looking sickly, it’s essential to take a closer look. Don’t assume it’s a weather or nutrient issue.
I like to inspect my plants on a near-daily basis to check for pest activity. The sooner you spot a problem, the easier it’ll be to deal with it.Yellow spots on leaves are sometimes the first sign of spider mite activity – though many people mistake these spots for disease or nutrient deficiency issues.
By the way, there are several other types of plant mites that can attack your plants. Spider mites aren’t the only ones!
Your plants can also be attacked by mites that target specific plants, like spruce mites, fruit tree mites, and honey locust mites.
How to Deal with a Spider Mite Infestation
Okay, you’ve spotted spider mites. Now what? Here are a few tips for handling the pesky (or should I say, pest-y) problem:
Thankfully, it’s possible to successfully eradicate spider mites from your house or garden plants. Spider mites are a pain in the butt, but they’re not impossible to defeat, like other stubborn pests.
Spider Mites Don’t Have to Be a Death Sentence
While it’s never fun having a pest infestation, you could do a lot worse than spider mites. With a little bit of elbow grease, know-how, and some good old fashioned prevention, these tiny bugs don’t have to be a death sentence for your plants.
Behavior and habits of spider mites
Spider mite (also called two-spotted spider mite) can be found on deciduous trees, evergreens, bedding plants and annual garden plants.
Ornamental plants: arborvitae, azalea, spruce and rose
Bedding plants: lantana, marigolds, New Guinea impatiens, salvia and viola
Garden vegetables: cucumbers, snap beans, peas, tomatoes and lettuce
Berries: blackberry, blueberry and strawberry
Spider mite infestations are particularly common during hot, dry summer weather.
How to identify spider mites
- They are very tiny, about 1/50th inch long.
- Yellow-orange in color, and have two dark spots, one on each side of the body.
- When a heavy infestation occurs webbing will also be present.
Life cycle of spider mites
These mites live through the winter as eggs on vegetation.
Check plants regularly for spider mites
- Examine plants for stippling and/or webbing.
- Look closely with a hand lens on the underside of discolored leaves for the presence of spider mites.
- You can also hold a white piece of paper or cardboard underneath potentially infested leaves; shake the leaves and look for spider mites that have fallen.
- Check garden plants every 3-5 days, especially under drought conditions.
Watch plants for signs of stress
Spider mites thrive on plants under stress. Keep plants well watered to reduce the chances of a spider mite attack.
Use a high pressure water spray to dislodge some of the spider mites. This can also wash away their protective webbing.
Natural enemies like velvet mites can control spider mites
Certain species of lady beetles (e.g. Stethorus sp.) and predatory mites (e.g., Phytoseiulus persimilis) naturally control spider mite populations.
Velvet mites feed on spider mitesVelvet mites are 1/16 — 1/8 inch long and are found on the soil surface. They are active during spring.
- Mite eggs and larvae can grow inside insects.
- They are harmless to people and gardens.
- Apart from spider mites, they can control other pests like, spring cankerworm, cabbage moth, lace bug and other arthropods.
If the spider mite population is high, natural enemies are not effective at controlling spider mites.
Using pesticides like carbaryl and imidacloprid for mite control can kill these natural enemies as well.
Insecticidal soap and horticultural oil
These are effective against mites and have little impact on people, animals and nontarget insects.These products will only kill mites that the pesticide directly contacts. They do not have any residual activity.
Target the underside of leaves as well as the top.
Repeat applications may be needed.
Effective active ingredients of residual pesticides include bifenthrin, deltamethrin and lambda cyhalothrin. Use these pesticides only when necessary, as they might affect a variety of insects.
Most spider mite infestations occur when it is hot and dry.
Water plants thoroughly before spraying pesticides for spider mites.
Spray in the early morning or early evening.
These steps will reduce the risk of further stressing plants and causing injury.
CAUTION: Mention of a pesticide or use of a pesticide label is for educational purposes only. Always follow the pesticide label directions attached to the pesticide container you are using. Remember, the label is the law.
Jeffrey Hahn, Extension entomologist and Suzanne Wold-Burkness, College of Food, Agricultural & Natural Resource Sciences
Identifying Spider Mites
Popular Plant Hosts
Spider mites are particularly attracted to the following plants:
- Beans/peas (pods)
- Ficus or Benjamin fig
Alternate weed hosts
- Various grasses
About the Author
Jessica Dawe owns a garden center and has been practicing integrated pest management and permaculture since graduating in 1995 with a degree in horticulture.
Spider Mite Overview
Types of Spider Mites
For a lot more information on the more specialized varieties of mites, read this document from the University of Hawaii’s cooperative extension.
Life Cycle of Spider Mites
Protonymph. Once a larvae has consumed enough food, they become temporarily inactive and develop into an eight-legged protonymph. Both stages of nymph can form webs.
This process normally takes about 14 days. However, in hotter environments, the process becomes much more rapid, and it can be as short as 7-10 days time.
Common Habitats of Spider Mites
The most rapid growth of spider mites is in hot, dry environments. While they do thrive in humid conditions, they seem to have more egg fertility in dry conditions, and they are commonly known to be problematic in dusty environments as well.
What Do Spider Mites Eat?
Frequently Asked Questions
Q: Where do spider mites come from, anyway?
While demolishing spider mites may take a little bit of time, it can be done — and your plants will be happier for it. Do you have any other techniques you’ve used in the war against mites? Let me know!