If you have asked yourself the question “Are red spider mites harmful to humans?”, after reading this article you’ll know that the only thing red spider mites are harmful to are the plants in your house, garden or greenhouse.
These tiny mites are very different from those red mites that can make the lives of backyard chickens pure hell or mites that bite or itch humans.
Want to Know More about Spider Mites?
In this short article, we will provide you with the basics on how to recognize and deal with red spider mites, including effective 100% organic extermination methods and preventative measures to control spider mite infestations.
Red Spider Mites Are Not Actually Red
That’s the first thing to know, because if you don’t, you’ll be searching for little red bugs on your plants!
These little arachnids formally known as Tetranychus urticae or two-spotted spider mites are not red.
They are usually a yellow-green color with two dark spots. They are little arachnids and not insects, and they are always under 1 millimeter long.
You will need a magnifying glass to observe these mites, but sometimes you can see the fine webbing they produce to attach their eggs to the underside of leaves.
Red Spider Mites Are Primarily a Plant Pest
These mites wreak havoc for farmers, gardeners and houseplant lovers alike.
They are great at destroying plants because they have an insatiable hunger for almost any plant they come near and thrive under hot, dry conditions.
Some of the many plants that the red spider mite attack include:
- Potatoes
- Tomatoes
- Peas
- Aubergine
- Maize
- Strawberries
- Roses
- Wheat
- Clover
- Coffee
- Cotton
Their tendency to infest fruits and crops means that they can cause substantial economic damage.
In agriculture-based economies (like Australia and South Africa), this pest which originally hails from South America, is considered a biosecurity risk.
The Red Spider Mite Has Mouthparts That Are Specifically Designed to Eat Sap
Red spider mites have sharp, sucking mouthparts that can easily puncture the cellular wall of plant cells and suck the juices and nutrients out of the cells.
As they are feeding they fill up with sap and produce a sticky, sweet liquid, called honeydew, which can also cause a problem for the plant.
They will feed on the plant cell by cell, and when numbers of this pest are high, a previously healthy plant can become quickly overwhelmed.
Their Rapid Lifecycle Means That Red Spider Mite Populations Can Scale Quickly
These small arachnids can reproduce quickly as they short in life stages.
We realize they multiply quickly as we can see their webbing on the undersides of leaves.
Females typically lay up to 200 eggs in their lifetime. The eggs are small, less than 0.1 millimetres, and lie on the white-orange spectrum. The larvae hatch and emerge with three pairs of legs.
The larva will go through two nymphal stages in which they gain a pair of legs and begin to change colour.
About the Size: Adult females are about half a millimetre long and have spots on each side of the body. Males are often a slight bit smaller.
Need-to-know Signs of Red Spider Mite Infestation
Given their highly vigorous feeding habits, red spider mites may inflict damage to all above-ground portions of a plant, but they prefer young, soft-new growth.
At first there are no visible signs of mites, but as the mite population increases the damage ramps up quickly, with plants succumbing to the infestation in just a few weeks.
The main clues to plant damage from red spider mites are:
- Whitened or yellowing leaves
- Speckled leaves
- Black sooty mould
- Loss of plant height and vigour
- Reduced crop yields
- White webs on the plants
- Mites and their eggs visible under magnification
Tackle Red Spider Mites Quickly to Bring an Infestation under Control!
As the red spider mite favors a broad spectrum of plant host, elimination is exceedingly difficult once they have been established.
The good news is the red spider mite has a number of natural predatory species that can be brought into play. There is also an array of materials that are very effective when applied in a topical treatment.
Ironically, it’s probably best to utilize organic methods to get rid of red spider mite because insecticides, while effective, tend to kill natural enemies. Also, some carbaryl insecticides can increase nitrogen content to leaves, actually causing an increase in red spider mites.
Moreover, the red spider mite produces rapidly, and therefore, a likelihood of creating resistance to a given pesticide preparation is probable.
Natural Predators of the Spider Mite
It is quite likely that natural predators are already feeding on the red spider mites in your garden.
You can also buy predator species to introduce to your garden for control and deterrent.
These are the main ones:
- Phytoseiulus persimilis is a type of predatory mite that actively preys on all life stages of red spider mites.
- In addition to Phytoseiulus persimilis, Amblyseius mite species can also be used to regulate red mite populations. One of the advantages of Amblyseius mites is that they establish year-round predation and can help diminish the numbers of red spider mites before they proliferate in the summer.
- Feltiella acarisuga is a predator larvae that consumes other plant pests that suck sap.
- Atheta coriaria is a rove beetle that consumes spider mites as well as gnats and thrips.
- There is also some evidence that ladybirds and lacewing larvae can prey on this mite.
Use These Sprays to Get Rid of Red Spider Mites
You can tackle red spider mites using simple organic sprays including ingredients like:
- Neem oil
- pyrethrum
- fatty acids
- and even water
Prevent & Keep Spider Mites Under Control
Keep spider mites under control by taking the following steps:
- Boost humidity: Red spider mites can’t stand humidity, so misting (or at a minimum) watering down plants with water can help deter them.
- Remove affected plants: Remove infested plants to quarantine them, to keep little red spider mites from spreading to other plants.
- Prevent ability to overwinter: The best way to target overwintering spider mites, is to remove any plant debris, stakes and dead leaves long before whatever spring means to you. Use a glasshouse daughter detergent to treat your greenhouse to make sure it is safe for your plants.
- There is the possibility that cultivation is key to controlling red spider mites: removal of weeds and dead plants can help red spider mites from spreading or overwintering in your garden!
Rounding Up
The red spider mite can be a frequent pest in gardens, but it’s not harmful to humans. Knowing what to look for determines how quickly you can keep them at bay using various organic-friendly approaches.