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How do you deal with spider mites?

Good article from Jorge Cervantes on the options available:

Have you had to deal with an infestation in your grow operation?

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Spider mites are one of the worst pests out there, in my opinion. They are hard to see, they breed about every 3 days and 90% of the eggs are female, who lay MORE eggs. Most gardeners don’t notice them until there are webs over their flowers. Staying on top of an integrated pest management schedule from day 1 and it will keep these nasty little suckers in check. Rosemary oil is a good way to put up a defense against mites. And for those of you who brew your own teas, As long as there are no nutrients in your tea (or a very small amount) you can filter the tea and spray it on the plants making it difficult for the mites to move around. I would love to hear how everyone else deals with their mite problems.

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[quote=“nickB, post:2, topic:706, full:true”]Staying on top of an integrated pest management schedule from day 1 and it will keep these nasty little suckers in check. Rosemary oil is a good way to put up a defense against mites. And for those of you who brew your own teas, As long as there are no nutrients in your tea (or a very small amount) you can filter the tea and spray it on the plants making it difficult for the mites to move around. I would love to hear how everyone else deals with their mite problems.
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One interesting trick I heard from an organic cannabis grower was that he likes to use diatomaceous earth. The microscopic jaggies from the diatom skeletons mess with insect exoskeletons and cause them to die of dehydration, and you can sprinkle the powder almost anywhere. It’s safe for humans to consume and it doesn’t harm plants, just insects.

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Lacewings. Lady bugs. Thrips. These are some of the best biological predators. With a strong ecosystem support for predatory insects they will take care of any infestation issues.

Diatomaceaous earth may help prevent them - but generally mites are in the foliage, the diatomaceaous earth ends up on the soil layer. Predatory insects and healthy plants (mites are more likely to attack weak plants) will provide a better resistance if you can support it.

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An ounce of prevention is worth pounds to cure. Cleanliness is next to buglessness.

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I like good biological controls Minute Pirate Bug, Orius insidiosus and Orius minnutus.
They are voracious predators. If you live where thistles or dandelions grow you can collect your own. The juveniles are best and easy to collect and store. A few pirate bugs go a long way. They are sensitive to neem oil, but not sensitive to insectiadle soaps.

I remember an old grower who washed is floors with boric acid. The boric acid when dry forms very small crystals. The crystals get into the joints of mites and they dehydrate. I think boric acid has an FDA and USDA label for food crop uses.

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What i do is call my renters insurance… Add fire coverage and… oh wait wait wait… that is how I handle my ex wife… :stuck_out_tongue: Eliminator the best things to use hands down.

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I have an friend who just used a shop vac to get mites under control at a grow operation. I was truly amazed at the before and after pictures.

He used insecticidal soap after a day of five people vacuuming.

I don’t know if I would have the temperament to vacuum up the infestation.

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I have personally witnessed this vacuuming of spider mite behavior from live cannabis flowers. It’s weird, gross and labor intensive…and the flowers look soooo sad afterward! I’ll offer the same advice to anyone considering mite hoovering: if you have webs all over your flowers so bad you have to go and vacuum them with a shop vac, you should go ahead and just burn that crop.

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Thrips are not beneficial insects! There are many excellent beneficial insect options though for spider mites, thrips, and just about any other nasty bug out there. The greatest thing about using beneficial insects is that there is not a single bug that has become resistant to being eaten or parasitized so they will continue to work for as long as there are bad bugs out there. I have several suppliers of beneficials that I would be happy to share with anyone that wants to look into this method of control.

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ron – Just for your information 6 spot thrips are the best mite predators…HANDS DOWN.

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Very interesting, @rflasch! What makes the 6 spot thrip a better predator than, say, a predator mite like Galendromus Occidentalis ?

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I spray suffoil, grandevo, venerate all through veg. I usually try and discontinue insecticides wk 2 flower and introduce cucumeris, persimilis, andersoni, orius, colemani. I use a combination of sachets and control release boxes/shakers all from bioline, it works great. Reinnoculate the room around wk 5 or 6.

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Sorry for the misunderstanding. I did not see the “6 spot thrips” in your post. They don’t seem to be commercially available unfortunately. I have not seen them offered by any of the companies I use for beneficial insects. Hopefully someone will see the value in them and make them available!

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I like Orius as front line defense on spider mites. Plus they are tough.

Same as adding thrips to control fungus gnats. Whenever new media comes into production.

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Who do you use as a biological supplier?

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I get great pricing from Global Horticulture.

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ron, that does not surprise me but if you ever have the chance be sure and get some they are unbelievable!

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@Growernick, in almond production, when midway in harvest we have to shut off irrigation so our trees may stress and the two spot mites can strike with a vengeance, because we have crop on the ground and in the tree it is not possible to use any miticides. I have seen trees webbed up be completely cleaned up by six spot thrip in 3-4 days UNBELIEVABLE. I believe the reason they are so effective is that their population dynamics closely match the mites they devour! As I told @ron I’m not surprised they are not commercially available (they are so voracious it would probably be a challenge to raise enough food to keep them viable) but just thought you might search them so that you recognize them, and be aware they are the unspoken heros in mite control!!

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Here is a great source for reasonably priced predators…The Fillmore Vitova insectory has been in business I believe since 1958

https://www.rinconvitova.com/

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