Killing Spider Mites Organically and Chemically

Spider Mites

Common visitors to outdoor and indoor gardens alike, spider mites, once established, can reek havok on any unsuspecting garden and gardener. The most common spider mite found in the garden is the Twospotted Spider Mite (Tetranychus urticae). These mites attack both evergreen and deciduous plants and can inflict plant fatality if not controlled. Killing spider mites can be a daunting task! Luckily there are many  techniques to kill spider mites. This article will discuss the most sucessful methods used for controlling this destructive pests.

Diagnose For Spider Mites:

Spider mites are very small, about the size of a pen head. This being said, they are often hard to see with the bare eye amongst the leaves of your plant. Sadly, most people do not even notice they have mites until damage is shown by the host plant. This damage may be observed as brown/yellow spotting on leaves or webbing. If spider mites are suspected, place a white sheet of paper under the plant and tap the leaves. The spider mites should fall onto the white paper. If the plant is infected, they will be observed as moving black dots on the paper.

How to Get Rid of Spider Mites:

Natural/Organic Control:

1. Soaking/Showering Plants - This method is considered to be one of the easiest and most effective ways to eliminate small populations of spider mites. The key here is to use a steady stream to shower the mites right off the leaves. Showering the plants can be done 1-3 times daily if desired. Mites usually totally disappear after a week of showering.

2. Create an Unfavorable Environment - This method mainly applies to indoor gardeners with the ability to change different aspects of the growing environment. Spider mites thrive in hot dry weather. Indoor gardens can suffer these conditions under inadequate ventilation and large grow lamps. Increase ventilation and use an ac unit to bring temperatures below 60 degrees F. Humidity can be raised by misting the plants several times daily. Take care to know what temperatures your plants can accept, 60 degrees F may be too cold for some plants.

3. Neem Oil - This natural pesticide derived from the Neem Tree is effective as both a preventative and a treatment against spider mites. Bottles of Neem Oil can be found at most garden and hydroponic stores. Using the mixing instructions on the package, spray the target plant thoroughly making sure soak the underside of the leaves. Follow with another treatment spray a week later. Mites should not exist at this point. Note that Neem Oil should not be sprayed in the three weeks before edible plants are to be harvested. Unpleasant tasting residues may exist on flowers/fruits/vegetables if used within this three week period.

4. Predatory Insects - Insects that dine on mites are a good option for those who garden outside, but can also be adapted to indoor use. The most useful of the predatory insects are lady bugs. These carnivorous insects will cut large populations down within days and will also keep your garden free of other harmful pests. Another viable option is predatory mites. These mites are exclusively carnivorous and will eat the pest population and then themselves, leaving you with a clean garden once again. Outside gardeners are encouraged to plant species that attract beneficial insects. Lady bugs and predatory mites can be purchased seasonally at nurseries and year-round online.

5. Foliar Spice Sprays - Although these are not typically listed as a treatment against spider mites, I have found one recipe that seems to control and eliminate populations. Boil 1Tbs Chili Powder, 1Tbs Nutmeg, and 1Tbs Cinnamon in one gallon of water for an hour. Strain the liquid through a coffee filter. (Chili powder boiled alone seems to do the trick as well) Once cooled, apply as you would Neem Oil. Note that before harvesting, the plants should be rinsed well to wash off any leftover flavor from the spice oils.

Chemical Control:

1. Insecticidal Soap - Mix 1-2Tbs Dawn dishwashing detergent into one gallon of water. Use as a foliar spray. Apply once a week, rinsing the plant thoroughly 30 minutes after application. For outside gardeners, make sure to apply in the morning hours when the temperatures are cooler. Applying during mid-day temperatures could burn the leaves.

2. Isopropyl Alcohol - Mix 1 part Isopropyl alcohol with 2 parts water. Use as a foliar spray. Apply once a week until the problem persists. The isopropyl alcohol kills the mites on contact and then evaporates quickly, leaving little to no damage to the plant.

3. Hot Shot No Pest Strip - These chemical strips are extremely effective at eliminating all indoor pests including spider mites. These strips can be found at Ace Hardware. Use with caution as this product could also have adverse affects to your own health if used improperly.

4. Pesticides - If you don't mind chemicals, this is the place to start. If health is a concern, this would be a last option. Chemical pesticides can be purchased at a variety of places and in a variety of formulas. There are mite specific formulas.

Spider Mites are so hardy of creatures that several of the above techniques may have to be adopted to eliminate a population. I would always suggest using the organic/natural methods before you jump into using a chemical approach. Good luck with your battles against these pests! Now that you know how to eliminate spider mites, go out there and knock em' dead.