Spider Mite Problem?

Discussion in 'Common Plant Problems and Solutions' started by wawona, Dec 7, 2006.

  1. wawona

    wawona The Trichome Connoisseur

    Here's a lil diddy i pieced together for a new faq that is in the works.

    if you have a mite problem it's a good read. if you don't wanna read it, then the summary is harvest or throw away the plants and clean everything that has anything to do with that room twice with bleach water and fog the room a cupl times and clean it again.

    Now, if you wanna learn something......

    ..............Spider mites are a common problem for the indoor cannabis grower and are commonly asked about on the boards. Spider mites grow from larvae to reproducing adult in a very short period of time. Which makes them very difficult to eradicate.

    To rid yourself of a problem you must first understand the problem. What follows is a combination of gathered information from experienced growers, countless websites and personal experience. I know that there are methods that have worked for folks that aren't mentioned here and there are prolly methods listed here that haven't worked for some. There's just no way to solve a problem in everybody's garden with the SAME solution. This is stuff that I know works and have seen work for others.


    Spider mites are not insects but are more closely related to spiders. These arachnids have four pairs of legs, no antennae and a single, oval body region. Most spider mites have the ability to produce a fine silk webbing. Spider mites are very tiny, being less than 1/50 inch (0.4mm) long when adults.

    Female, Male, Larva



    Spider mites have tiny mouthparts modified for piercing individual plant cells and removing the contents. This results in tiny yellow or white speckles. When many of these feeding spots occur near each other, the foliage takes on a yellow or bronzed cast. Once the foliage of a plant becomes bronzed, it often drops prematurely.

    Heavily infested plants may be discolored, stunted or even killed. Web producing spider mites may coat the foliage with the fine silk which collects dust and looks dirty.

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    Spider mite species seem to be warm weather or cool weather active pests. The twospotted, European red, honeylocust, and oak spider mites do best in dry, hot summer weather. The spruce and southern red spider mites do best in cool spring and fall weather.

    Most spider mite activity peaks in warmer/drier gardens or climates. They can develop rapidly in these conditions, becoming full-grown in as little as a week after eggs hatch. After mating, mature females may produce a dozen eggs daily for a couple of weeks. The fast development rate and high egg production can lead to extremely rapid increases in mite populations.

    All spider mites go through the same stages of development. Adult females usually lay eggs on their host plants. The eggs hatch in days to weeks into the first stage, called a larva. Larvae are round bodied and have only three pairs of legs. The larvae feed for a few days, seek a sheltered spot to rest and then molt into the first nymphal stage. The first nymph now has four pairs of legs. The first nymphs feed a few days, rest and molt into the second nymph. The second nymphs feed, rest and molt into the adult stage. The males are usually the size of the second nymph and have pointed abdomens. The females have rounded abdomens and are the largest mites present.

    Most spider mites spend the winter in the egg stage but the twospotted spider mite overwinters as adult females resting in protected places. The fact that the eggs lay dormant is another big problem. you can have all of the lil buggers killed and the eggs hatch on down the road. That's why you find out later that multiple applications of solution/treatment are needed to completely rid yourself of the spider mite problem.

    Control Strategies

    Early detection of spider mites, before damage is noticed, is important. The tiny spider mites can be detected by taking a piece of white paper or cardboard and striking some plant foliage on it. The mites can be seen walking slowly on the paper. If 10 or more mites per sample are common, controls may be needed.

    Option 1: Cultural Control - Syringing- Since rainy weather seems to knock off spider mites, using a forceful jet of water from a hose (syringing) can perform the same task. This technique also helps conserve natural predators. A regular syringing can keep spider mites under control, as well as remove the dust that collects on foliage and interferes with mite predators. Disruption of the webbing also may delay egg laying until new webbing is produced. Sometimes, small changes where mite-susceptible plants are located or how they are watered can greatly influence their susceptibility to spider mite damage.

    Option 2: Cultural Control - Quarantine and Inspection - The twospotted spider mite is often introduced on infested bedding and house plants. Carefully inspect the lower leaf surface for any signs of mite activity. New plants should be quarantined from other plants until you are sure that no mites are present.

    Option 3: Biological Control - Predators - There are numerous insects (lacewings and lady beetles) that prey on spider mites. However, the most commonly sold predators are other types of mites. Predatory mites (usually Phytoseiulus spp., Amblyseius spp. or Metaseiulus spp.) can be purchased and released onto infested plants. Be sure to check listings to determine which species is appropriate. Some species are host specific and each predator works better under different weather conditions. If predators are used, do not apply pesticides that will kill them.

    Option 4: Chemical Control - "Soft Pesticides"- Most spider mites can be controlled with insecticidal oils and soaps. The oils, both horticultural oil and dormant oil, can be used. Neem oil is a commonly used, readily available product. Thre are many others. Horticultural oils can be used during the summer at the 1 to 2 percent rate. Higher rates of horticultural oil (3 to 4 percent) or dormant oil are useful for killing mite eggs and dormant adults in the fall and spring. The insecticidal soaps are useful in the warm season. Remember that mites are very tiny and soaps and oils work by contact only. Therefore, THOROUGH coverage of the plant is necessary for good control.

    Good old, reliable garden-grade sulfur still appears to be the best control for spider mites, and is also an economical, effective fungicide for control of diseases at the same time. Sulfur can be purchased in powder or liquid form. I find the liquid more effective, but the limitations of spraying are often a problem as it cannot be sprayed when temperatures are very warm or very cool. Winds must be calm, and bright sun hours away. This can be overcome by spraying late in the evening or very early in the morning. The biggest drawback of the sulfur is the smell which can last for days.

    Having said that, strains of spider mites resistant to pesticides frequently develop, making control difficult. Because most miticides do not affect eggs, a repeat application at an approximately 10- to 14-day interval is usually needed for control.

    Option 5: Chemical Control - Miticides - Spider mites are usually not killed by regular insecticides, so be sure to check the pesticide label to see if "miticide" is present. Pesticides claiming "for mite suppression" are usually weak miticides and will not perform well.

    Option 6: wawona's tilt- The breakdown and clean method- Having had a spider mite problem in 2 rooms, simultaneously, I feel that I have something to share. I highly suggest you find a way to control and minimize the problem and harvest what you can. After harvest, break down the room and clean EVERYTHING that was in there with bleach water, fog the room a couple times and then wipe the room down with the bleach water AGAIN. (We'll discuss the foggers in a bit) When I say clean EVERYTHING in the room, I mean clean EVERYTHING that has come in contact with those plants or that room. Fans, water jugs, duct work, containers, meters, etc....... It would be a great idea to put a fresh coat of paint on the walls and/or replace the wall covering.

    That's the easiest, most assured way to get rid of them. I know it doesn't sound that easy, but if you just do this from the get go you skip all the junk pesticides and recipes when you are just gonna end up doing the breakdown any way. I found this out the hard way. I tried all of the quick fixes and none of them GOT RID of the problem. If I had listened to people and taken the advice tha I am giving here I could have cut months off of the problem.

    Remember, it is very difficult, if not impossible, to completely get rid of spider mites "in grow." You can control them enough to keep the plants alive and even get a bountiful harvest, but they will still be there. It's really more about supression as long as the grow is in operation.

    So, how do you control the pest problem so you can salvage at least some harvest???

    The first thing you gotta do is to keep the grow op clean. I mean spotless from here on out. Pick up all of those dead leaves and wipe those fans down at the least.

    If you notice the problem at an early stage it is much easier to contain. Once the plants are more mature, and have lots of foliage for the mites to hide, it definately becomes more of a matter on control rather than eradication. It is much easier to get FULL COVERAGE on smaller plants. FULL COVERAGE is the key no matter what product you decide best suits your garden.

    I found that starting on the plants with a product calledSMC leaf wash. or a similar product. SMC Premium Quality Leaf Wash is a 100% organic blend of pure plant oil extracts. Used as a mist spray, SMC Leaf Wash helps to keep valuable plant leaves free of dust and and other airborne debris, insect eggs, soil, and other contaminants that can restrict a plant's leaves ability to function properly. This should be used at least three times 5-7 days apart. This product can be used even before you have a mite problem as a preventitive method. The leaves are uninhabitable for mites after this product is applied. Their slogan is, "a clean leaf is a healthy leaf."

    As was mentioned before, these lil pests become immune to a single control product, if used continuosly by itself. I find it helpful to use a room fogger bewteen treatments with the SMC to help kill any pests lingering in the room and on the equipment. Not to mention a lil extra shot to the plants is helpful. Make sure you turn off all fans wile using the foggers. I use the fogger 2 times with 1 week betwen the uses. Make sure the fogger you choose to use is labled "plant safe". The fogger that I have had success with was Pyrethrum TR. I also tried Doktor Doom Total Release Fogger without much luck. The pyrethrum fogger contained a much higher concentration of the active ingredient, Pyrethrin.

    So as a quick review; Use the smc leaf wash or equivelant and the room foggers to control the mites so you can get to harvest. After harvest, break the room down and clean thouroghly and fog. Keep the room clean and use the SMC leaf wash on young clones and seedling to keep from getting the problem in the future.

    Easy enough. :)

    BTW, during this whole process, which could take up to a month, make sure that your plants are free from extra stress. Make sure they get plenty of fresh water and air and that the temps are not too hot.

    Good Luck!!

    One last piece of advice that may be the most critical in the avoidance of the problem. DO NOT ACCEPT PLANTS FROM OUTSIDE OF YOUR GROW!!!! That's how I got mites and that's how A LOT of folks get 'em. JUST DON'T DO IT.

    NOTE: Disclaimer - This publication may contain pesticide recommendations that are subject to change at any time. These recommendations are provided only as a guide. It is always the pesticide applicator's responsibility, by law, to read and follow all current label directions for the specific pesticide being used. Due to constantly changing labels and product registrations, some of the recommendations given in this writing may no longer be legal by the time you read them. If any information in these recommendations disagrees with the label, the recommendation must be disregarded. No endorsement is intended for products mentioned, nor is criticism meant for products not mentioned. The author and Growkind

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