Get Rid of Spider Mites Once and for All

Spider mites are common pests that growers all over the world battle on a daily basis and this post is going to show you how to get rid of spider mites fast and good growing practices to keep them out.

Mites feed on all types of plants like vegetables, fruit trees, vines, berries, cannabis, indoor and outdoor ornamental plants.

They reproduce very quickly and can become a huge problem in a matter of days destroying plants rapidly.

Although related to insects, they do not fall under the same classification.

Mites are part of the arachnid class along with spiders and ticks.

Adult spider mites can be red, yellow, orange, green, or brown in color.

Notable spider mite species to mention are the Pacific spider mite, strawberry spider mite, European red mite, Carmine spider mite, and the most common one of all… the two-spotted spider mite (Tetranychus urticae).

Spider mites are tiny little creatures and when populations are low, you’ll need to identify them using a handheld microscope, eye loupe, or hand lens.

Click here to get a FREE illuminated handheld microscope. 

When spider mites become a major problem, they’ll be easy to identify by their huge, thriving colonies and webbing like the photo below…

Before moving on to control measures, its important to understand the full life cycle of spider mites… and for any pest you’re trying to control for that matter.

Our friends at Koppert Biological Systems produced a fantastic video describing the life cycle of a two-spotted spider mite, which is basically the same as other webbing spider mites and the major subject of this post.

Damage

Spider mites cause damage by feeding on plant tissue and plant sap.

They are mostly found on the underside of leaves where they suck out the juicy contents of the plant cells, feeding on them one-by-one.

Just a few feeding spider mites really isn’t much of a problem, but very high populations feeding in unison can cause some serious damage in a short period of time.

As feeding continues, the dead cells turn yellow or reddish and leaves start dropping off.  Eventually the entire plant will die.

Reproduction

Spider mites reproduce rapidly and especially in hot weather which is why populations are typically higher from June through September.

Given favorable conditions, a generation can be completed in less than a week.

Eggs are laid on the undersides of leaves.  The larvae that emerge, are basically colorless with two dark red eyes.

Once the larvae start feeding, they become light green, brownish, yellow, and even dark green.

They will molt a total of three times, each time shedding their skin, and then finally turn into adult mites.

The color of the adults often depends on the crop their feeding on.

Biological Control

Spider mites have many natural enemies, which can significantly keep them under control so it’s important to avoid spraying toxic, broad spectrum, chemical pesticides that disrupt their life cycles.

One of the most effective natural enemies is actually a spider mite itself, the western predatory mite.

Other important natural predators are sixspotted thrips, spider mite destroyer lady beetle, minute pirate bugs, bigeyed bugs, and lacewing larvae.

Some of these beneficial insects can be introduced to establish healthy populations, but its best to maintain favorable environmental conditions for them to occur naturally and thrive.

That’s why you want to avoid the use of broad spectrum, toxic, conventional pesticide applications that can not only kill beneficial insect populations, but breed massive resistance in spider mite populations, compounding the problem.

Cultural Control

So what are some measures you can take to prevent spider mites making a home on your plants in the first place?

Dusty, dry conditions often lead to mite outbreaks so regularly watering down pathways and other dusty areas is a good practice.

You can also water down your plants on a regular basis too.

Basically you want to maintain a clean growing environment and plants as a good means of prevention.

Dirty, dusty, dry plants seem to invite all kinds of insect pest problems… not just spider mites.

Now if you’re growing indoors and have a serious mite infestation that just doesn’t seem to go away no matter what you do, here is a more dramatic option but may be your best chance…

Start over and sterilize grow room.

Clear out all your plants and spray the entire room with a 30% bleach solution.  And that means everywhere…ceiling, floor, and all the equipment.

This will kill all remaining spider mites but will also kill just about anything else like any problematic molds you may have in the area.

After this extreme sterilization, you’re going to need to keep up with regular maintenance applications mopping the floor once or twice a week and spraying walls at least once a month.

Now that you have a clean slate, very important to maintain a preventative approach by making regular pesticide applications but only using effective, organic miticides that you can see in the next section.

Organic Pesticides and Miticides

When natural enemies aren’t getting the job done and your preventative measures aren’t working any more, then its time to take action and treat for spider mites.

But as mentioned before, it’s best to use non-toxic, multi-mode action, organic pesticides and miticides.

This is for two main reasons…

1. Broad spectrum, toxic, chemical pesticides may work for a while, but can be detrimental to other beneficial organisms that help you keep spider mites under control.
2. Spider mites breed like crazy and can develop resistance very quickly to the regular use of chemical pesticides, that typically employ only one mode of action.  In fact, studies have shown that some insecticides actually stimulate mite reproduction.

Plus organic pesticides are just safer and easier to work with not having to worry about dangerous pesticide exposure, to you as an applicator, or any toxic residues after harvest.

But when treatment is necessary, below is what you’re going to want to use for best results:

Botanical Oils (Insecticidal Oils)

Plant-based botanical oils are very effective when spider mites are present providing quick knock-down, contact control that smothers mites by clogging their spiracles, or breathing pores, and breaking down their outer cellular membrane.

Although some have repellent properties, in order for them to work properly they must come into direct contact with spider mites.

There are a number of botanical oils formulated around plant extracts such as cottonseed, garlic, clove, cinnamon and others, but rosemary, peppermint, and soybean oil have shown to provide the most consistent miticide activity in agricultural crop trials.

That’s because not only do they provide a solid, lethal, contact mode of action, but the rosemary and peppermint oils, primarily, consist of complex terpenes and terpenoids that are very insecticidal in nature.

These oils also function as neurotransmitter disruptors which confuses and repels insects from feeding on your plants.

That’s why we formulated our product, Mantis EC Botanical Insecticide/Miticide, with these key active ingredients.

CLICK HERE for technical information, trial data, and testimonials on Mantis EC.

Although horticultural oils like white mineral oil and other paraffin oils fall under this category too, they don’t provide the added benefits of select botanical oils like repellency, neurotransmitter disruption, and anti-feeding properties.

Plus they are petroleum based and depending upon the quality and grade, they are more likely to burn your plants.

But before using botanical oils to treat your plants, be sure to follow these important use recommendations:

• Mixing:  Make sure you shake well before using and be sure to mix well with water by giving an aggressive shake or constant agitation.
• Coverage:  Although a good botanical oil formulation also has repellency properties, their main mode of action is contact so be sure to get really good coverage applying solution to all parts of plant. Both sides of leaves, stems, branches, and every little nook and cranny spider mites like to hide.
• Frequency:  Apply at first sign of spider mite presence and continue applications every 4-7 days until infestation is controlled.  After that, regular maintenance sprays at lower rates every 10-14 days keeps populations from coming back with a vengeance.
• Do not use if temperatures are expected to be above 85 degrees fahrenheit.
• Spray in early morning or evening when it is cooler.
• Do not apply in mid-day sunlight or when grow lights are turned on as temporary leaf burn may occur.
• Plant Safety:  There are some cheap, poorly formulated, botanical oil based products in the market that will burn your plants so be sure to ask around or test before applying to entire garden.

Click here to add Mantis EC to your arsenal!

Insecticidal Soaps

Insecticidal soaps, which consist of potassium salts of fatty acids, are going to work similar to botanical oils providing the same knock-down, contact control.

However unlike botanical oils that provide multi modes of actions, insecticidal soaps work solely by direct contact.

For this reason, good coverage and direct contact with spray solution is crucial for good spider mite control.

Good use recommendations are similar to botanical oils that you can review below…

• Mixing:  Make sure you shake well before using and be sure to mix well with water by giving an aggressive shake or constant agitation.
• Thorough Coverage:  Spray both sides of leaves, stems, branches, and every little nook and cranny where spider mites like to hide.
• Frequency:  Apply at first sign of spider mite presence and continue applications every 4-7 days until infestation is controlled.
• Do not use if temperatures are expected to be above 85 degrees fahrenheit.
• Spray in early morning or evening when it is cooler.
• Do not apply in mid-day sunlight or when grow lights are turned on as temporary leaf burn may occur.
• Do not make more than 3 sequential applications with 5 day apart as sometimes the plant’s cellular cuticle can be stripped down after back-to-back uses.

Click here to try some insecticidal soap!

Azadirachtin & Neem Oils

The azadiracthin compound is one of the oldest natural biopesticides in the world that is extracted from the neem tree and was first discovered in India ages ago.

Also classified as a botanical insecticide, azadiracthin based products typically come in two forms… 1) the isolated azadirachtin molecule in a formulated product or 2) neem oils.

Although neem oils do contain a small amount of azadirachtin compounds and can also be useful for powdery mildew treatments, for spider mite control I prefer to use products that are formulated using the isolated azadirachtin compound.

The azadiracthin compound is carefully extracted from neem tree seeds and is the part that has the most insecticidal activity.

Neem oils are simply mechanically extracted oils from all the biomass of the neem tree… leaves, twigs, seeds, and all, with a lower azadirachtin concentration and that’s why they are typically much cheaper.

Azadirachtin is a unique biopesticide as it mainly functions as an insect growth regulator affecting spider mite’s ability to molt and their growth stages; but it also has other modes of action such as repellency and antifeedant properties.

CLICK HERE to get some AzaMax!

Diatomaceous Earth

Diatomaceous earth, or DE, is one of my favorite natural pest control products because its so unique and diverse.

DE is a dust made of the fossilized remains of single celled phytoplankton called diatoms.

DE is a natural mineral and is used in a variety of ways but it is also a great organic pesticide for spider mite control!

To learn other ways diatomaceous earth can be used in your home and garden, check out my post Diatomaceous Earth is DYNAMITE!

Diatomaceous earth kills spider mites through a contact desiccation mode of action.   The absorptive properties of DE easily remove the cuticle’s outer waxy layer which results in the loss of a mite’s ability to maintain proper fluid levels, ultimately resulting in death.

*Not all DE’s are structurally the same and this is why it is important to use a DE with high surface area and porosity for optimum insecticidal activity.

IMPORTANT: make sure you use DE that meets Food Codex Standards and contains less than 0.1% crystalline silica content.

DO NOT USE POOL-GRADE DE, which is crudely processed, chalked full of crystalline silica, and is dangerous to breath in.

DE is not a silver bullet and not going to completely annihilate spider mite infestations, but its a good first line of defense and helps prevent mites from establishing colonies in the first place.

So try keeping a coat of DE on your plants at all times and you’ll see the benefits.  Not just on spider mites, but discouraging other insect pests as well.

When applied either in solution with garden sprayer (½ to 1 cup per gallon water) or dry using a duster, DE is one of the most persistent organic pesticides providing residual plant protection up to 10-14 days as long as it doesn’t rain or get wet.

Click here to get a bag of Mantis DE! 

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PS: If you’d like for me to send you a Mantis Hand Lens for FREE, click here.