How to deal with mites

[occidentalis]

We have an on going battle with mites in our lab. In case anyone else ever gets mites in their cultures and wants to know what to do, here is my method of cleaning up mite infested cultures.

First, how do you know if you've got mites? The easiest way to tell is by little trails in the condensation on the lid of the dish. Sometimes if you look really close or use a microscope you can see the bubbles at the end of these trails slowly moving around. They are being pulled by mites. You may also see little track marks of contamination on the agar. The mites carry around bacteria on them and you'll get little trails of visible mite footprints. On a well-colonised plate of fluffy mycelium, you may see dirty 'holes' where the mites have carved out caverns in the mycelium which become stained with mite shit. You can see these with the naked eye as little dark spots in the white mycelium.

The first thing you need to do is isolate any cultures that are clean and keep them away from the dirty ones. What I do is put them inside two ziplock bags, and spray ethanol in the space between the bags (ie inside the outer one). Make sure the bags are tightly closed. Then keep these in a clean room, or box, or whatever. Just make sure it's a mite-proof environment. Sticky pads are good - If you want to improvise, you could probably make something out of strips of duct tape.

To deal with infested plates, a dissecting microscope really helps. You can fairly easily see the mites, their eggs, and the dirty little houses they've made in the mycelium. Then you just take subs from areas where you think there are no mites. Take really small subs (even just scrape off a bit of wispy aerial mycelium). Or, you can cut a chunk of agar out, and slice it horizontally so you only get the bottom bit with no aerial mycelium and hopefully no mites. If you don't have a dissecting microscope, you may still be able to do this by looking for their traces and taking really small subs. Take lots and put them on one plate each. Then put the plates in separate ziplock bags (or you could do 2 to a bag if you want), then put all of those bags into a big bag, and spray ethanol inside. That should stop your plates being cross contaminated if some do have mites. Put these into a second room or box for "possibly infested material". Check them after two days and see if any are infested. If they are, chuck them or sub again from them. After a week, they should be able to know for sure if they are infested or not. If not, take them out of their bag, put them in a clean bag, and put that into your 'clean' box or room.

Then, keep a third room or box for any "definitely infested material" that you really need to keep. Keep that one far away from the others!

Mites are a real hassle but it is possible to rid yourself of them with a bit of work.

You can get miticide chemicals (dificol is one), but I am told by someone who tried out several compounds and several methods of using them that they are not very effective in the petri dish environment.

[ENtiTY]

Thanx creah

Hopefully I won't need this info but its handy to know. Do these mites specifically live in fungi tissue or do they live anywhere?

Cool pic! Know thy enemy!

[swinelover]

Have you tried neem powder,I find it an effective bio agent. Tests should be done to find the tolerance of cultures being cultivated!