12

I am looking for an extensive answer with references that:

  • lists many of the plants that can be attacked by spider mites
  • the conditions that encourage them
  • brief information about their lifecycle
  • how to identify them and the damage they cause
  • all the control methods, organic or pesticide based with detailed instructions on how to use the control agent
  • 1
    me too. Every year I get these on some of my indoor plants. Taking the plants outside usually seems to kill, or at least control, them. Whether it's the sun, wind, rain, or some combination, I don't know. I can control them indoors by spraying with soapy water frequently but never seem to get completely rid of the little suckers. – DrewJordan Mar 25 '16 at 20:28
9
+250

How to check for spider mites.
Spider mites live on the underside of leaves, and are reddish brown or pale in color, oval-shaped, and very small.
Obvious signs of infection are white webbing, yellow blotches on leaves, and even silver or bronze streaks. If an infection gets particularly bad, leaves can start falling off. To confirm an infection, take a leaf and shake it over a sheet of paper. A few spider mites will fall off. They can be then looked at with a magnifying glass.
Check more often in dry and dusty conditions.

Dealing with them naturally
* Wipe leaves with a sponge regularly.
* Spray plant with a hose on high pressure, targeting the underside of leaves.
* Rubbing alcohol on leaves will kill spider mites.
* Remove infested leaves immediately and discard in trash.
* Remove weeds, particularly broad leafed ones, because these give spider mites hiding places.
* Make your own miticide: Boil a quart of water then take it off the heat. Once it has cooled slightly add two teaspoons of crushed fresh garlic. Once it has cooled, add a squirt of dish soap to the tea, and then put ina spray bottle. Spray the underside of infected leaves with the tea every three days.
* Encourage the presence of ladybugs and other insects that prey on spider mites.
* Some other natural miticides: Neem oil, rosemary oil, cinnamite and pyrethrum.

Dealing with them chemically.
* Use sulphur.
* Buy products at a garden store to kill them. Follow the manufacture's instructions.
* Use a strong insecticidal soap inside.

Plants that are highly prone

Some plants that are highly prone to spider mite attacks are listed here: Alocasia 'Frydek.'
Aspidistra elatior 'Milky Way.'
Chamaedorea elegans.
Calathea roseo-picta
Codiaeum variegatum 'Petra.'
Cordyline fruticosa 'Kiwi.'
Hedera helix (English ivy)
Pachypodium lamerei
Strelitzia nicolai.
Acorus spp. (sweet flag, Japanese rush)
Adenium obesum (desert rose)
Alternanthera spp. (including A. dentata 'Purple Knight')
Aspidistra elatior (cast-iron plant)
Breynia disticha cvv. (snow bush, snow on the mountain)
Brugmansia cvv. (angel's trumpet)
Chamaedorea seifrizii (bamboo palm)
Cissus rhombifolia (grape ivy)
Colocasia cvv. (elephant ears)
Datura cvv. (devil's trumpet)
Dieffenbachia spp. (dumb cane)
Dracaena marginata (Madagascar dragon tree)
Dracaena thalioides
Gardenia jasminoides (gardenia)
Hedera canariensis (Algerian ivy)
Heliconia psittacorum cvv.
Hibiscus rosa-sinensis (tropical hibiscus)
Impatiens spp. (impatiens)
Jasminum sambac (jasmine)
Maranta leuconeura cvv. (prayer plant, rabbit tracks)
Musa spp. / Ensete spp. (ornamental banana)
Plumeria cvv. (frangipani)
Polyscias balfouriana (balfour aralia)
Polyscias fruticosa (ming aralia)
Primula vulgaris (primrose)
Ravenea rivularis (majesty palm)
Schefflera arboricola (umbrella tree)
Schefflera elegantissima (also known as Dizygotheca elegantissima) (false aralia)
Stromanthe sanguinea cvv.

Hope I helped

References: http://plantsarethestrangestpeople.blogspot.com.au/2010/01/list-houseplants-which-are-highly-prone.html http://m.wikihow.com/Get-Rid-of-Spider-Mites

  • I'm not sure your links to PlanetNatural add to this answer. It looks like advertising spam and may be removed. – kevinsky Mar 31 '16 at 16:38
  • I have edited to remove references to PlanetNatural – codeman Apr 1 '16 at 3:17
6

There are so many species (and genera for that matter) of spider mites that one set of guidelines is likely not going to fit all of them. If you ask about a specific kind of spider mite, you might get a better answer (provided much is known about it).

I recommend learning which spider mites are indigenous to your area, and observing how they behave. Expect there to be differences between them and spider mites in another area, however small or large.

As for the spider mites in my area (which is in southwestern Idaho), I have no idea what kind they are, but they're pretty interesting creatures:

  • Firstly, they're almost always invisible.
  • Secondly, they don't really do any noticeable damage to outdoor plants unless it's both hot and dry. The hotter and dryer it gets, the more damage I notice.
  • On indoor plants, they seem to do the least damage when it's cool and the most when it's warm (whether or not it's dry). So, if you don't heat a room that has plants in it, they may cause less damage.
  • Spraying outdoor plants down with regular water every day or two seems to stop them from damaging the plants (it works for indoor plants, too, but it's more tedious and needs to be done more often). I'm not really sure why. Maybe they're thirsty. Maybe it sprays them off the plants. I don't know, but it works (no need to use soap and stuff; regular water works fine).
  • They do more damage to peppers indoors than outdoors (they left my outdoor peppers alone, both the hot and the sweet peppers).
  • They very noticeably afflict the following outdoor plants: apple trees, watermelon, ground cherries, garden huckleberries, tomatillos, pepino melons, eggplants, and roses (the leaves).
  • They affected litchi tomatoes, too, but less severely.
  • They seem to afflict regular tomatoes on rare occasions, but leave most of them alone. They may have affected my cucumbers and Shark Fin Melon, but I'm not 100% sure.
  • My muskmelons and Red-seeded Citron watermelon were mostly unafflicted, but that could have just been the location (hopefully not, though).
  • They seem to be capable of infesting most houseplants, although the damage seems to be less than to outdoor garden plants when it's hot and dry (and less than the damage to indoor peppers).
  • They did not noticeably affect the following outdoor plants: peppers, Ethiopian eggplant (Burkina Faso), weeds, peach trees, nectarine trees, cabbage, arugula, milk thistle, mizuna, our apricot tree, and other stuff.
  • Attempting to entirely eliminate spider mites does not seem to be a very practical endeavor by most approaches. However, you might try predatory mites, which are supposed to eat them. Be careful not to kill any predatory mites that already exist (they may appear to be spider mites if you're not careful). There may be effective pesitcides, but spider mites can gain resistance fairly quickly, as I understand it.
  • On indoor plants they spin webs from the soil to the plant often (especially when either the soil dries out or first becomes wet). I'm not really sure why they do this, unless they partially live in the soil or something. However, it's possible that if you cut them off from the soil, they may be less prolific. So, mulching might potentially help considerably. We didn't mulch any of our plants that have had spider mite problems. So, I can't tell you how effective this is.
  • On my indoor pepper, spider mites caused significantly less damage when I applied sea minerals, but they would eventually cause damage again until I used them again. I recommend a foliar spray since that would be less likely to make the soil too salty quickly. The excess salt in sea minerals can indeed cause problems if you use too much (but it takes a while before it gets to that point). I purposefully used too much (directly in the soil) to discover this. It's possible that using sea minerals on the leaves may protect the plant more than applying it to the soil does, but I'm not sure, since I haven't tried it, yet (my pepper plant is now in a container outdoors; hopefully it'll recover from all that salt now that it has new soil; the roots may have rotted, however, perhaps due to the stagnation of growth caused by the excess of sea minerals or the smallness of the container).
  • On my indoor pepper, spider mites caused by far the most damage on new growth.
  • I've read that spider mites can contribute to the spread of anthracnose. I'm not sure if that's true, but it seems anthracnose does perhaps often coincide with spider mite infections. So, if you grow watermelons, anthracnose-tolerant varieties may be helpful.
  • Spider mite webs are said to help protect them against predators, but in my observation, they seem to use them to travel to new locations, too. Although spider mites are said not to move very fast (I can't see them; so, I don't know if this is really true for our species), they do infect neighboring plants rather quickly indoors (within a day or two). They may or may not spread so quickly outdoors. Clearing the webs might help some.
  • The damage to outdoor plants appears different than the damage to indoor plants. Affected outdoor plants may have webs on them. The leaves may appear speckled. On indoor plants, they seem to cause leaf deformities, and little spots that can turn into edema if it's humid. They can spin webs to close up leaves. They can cause leaves to curl.
  • Faster-growing plants seem to have an advantage. You might consider giving them more nitrogen to see if it helps. Our plants had lots of rockdust and potassium, which could slow growth increase the need for nitrogen. They were kind of slow-growing.

Anyway, the Wikipedia article on spider mites is quite insightful. It talks about a lot of the stuff you're probably interested in.

Overall, in summary, this is what I would recommend:

  • Spray your affected plants with water every one or two days.
  • Get and/or attract predatory mites.
  • Getting ladybugs wouldn't hurt, either. I heard a rumor that they'll eat spider mites. I don't know if this is true, however. I got ladybugs, but spider mites were still a huge problem (I only got one batch of them, once, though).
  • Experiment with mulching.
  • Maybe experiment with foliar sprays of sea minerals to see if it helps.
3

Spider mites attack just about everything, it seems. You can control them with soapy water with some vegetable oil in it. Be sure to use soap, not detergent. I buy Kirk's Castile soap & shave a bit into the water I plan to drench the plant in. You mix it well, of course - for small amounts (1 gallon or less, e.g.) I mix with a standard kitchen mixer or get a paint mixer & use a drill (prefer battery-powered to avoid the possibility of shock that exists if a corded one gets wet). Another possibility you can use on many plants is to make very thin batter of dry milk, water and flour & drench the plant with it - let it dry, then rinse the plant. When the batter dries, it shrinks. This kills any mites & suffocates their eggs. Not all plants like milk, though, so be sure to rinse the earth well, too. Obviously, you don't let this sit for hours before rinsing. If you have the problem on apple trees, you want to rinse the earth under the tree inside the drip line as soon as the branches stop dripping without waiting for the tree itself to dry; apple trees dislike milk in their roots & won't set fruit if they 'drink' milk. Good luck!

2

Keep a cotton bud dipped in tea tree oil very close to your indoor plant. This will keep insects away from your plant.

  • 1
    Do you have any references for this? I am looking for an extensive answer. – kevinsky Mar 30 '16 at 16:16

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