mites? disease?

Tue Jan 10, 2012 3:09 am

Hello, just wondering if anyone can verify what the white areas are on the picture. I'm concerned about spider mites or some other disease. I am very new to bonsai and horticulture in general.

Now there are some water/salt spots from water that was sprayed on the plant (i need to cease using salty, water-softened water). However, the area of concern is at the nodes -- I am noticing a small amount white spider-web-like substance at a few nodes.

I just want to isolate this Jade from my other plants if it is indeed infected.

Many thanks!

DSCI0127 by freefall365

DSCI0128 by freefall365, on Flickr

Tue Jan 10, 2012 8:28 pm

I can't see your pictures, but I have had spider mites in the past...and I've had them bad.

Most often, you can see the spider mites. Simply flip the leaves in the area you are concerned with and watch to see if any of the tiny specks you see on the underside of the leaves are moving. You can also see the webbing better if you give the plant a light/fine spray misting. The water will stick to the webbing making them more pronounced.

I had the 'red' variety, so they were more visible than the gray or yellowish variety (2 spotted). The red mites appear to be specks about the size of grains of salt and actually appear black on the leaves. They spread to everything that they can reach. I had them on several plants and they even set up shop on my humidifier at one point. I let them spread because I was breeding predator mites at the same time but I released the predators too late and they simply never caught up until most of my plants were dead. It was more of an experiment than anything, so it was more fun to watch them eat each other than anything. The plant loss was minimal because the project was a small scale project, so it didn't matter all that much in the end.

There are many ways to get rid of them. The most common method to remove is a firm spray of water. This will typically knock them off the leaves but some bonsai plants might be too fragile for that - I'm not a bonsai guy, so I simply don't know. You can also use your fingers to lightly rub all leave surfaces - this will kill them.

There are many sprays out there on the market as well. I use an pyrethrum aerosol product called Doktor Doom by Hydrofarm. It just takes a light misting every couple weeks to keep them in check. You have to hit the bottom of the leaves, though, or you will be wasting your time and your spray.

And as noted above, you can buy predator mites to eat the spider mites. There are many problems with this. While the predator mites breed twice as fast as the regular mites, you have to catch them early enough in the process to give the predators time to catch up before the regular mites kill your plants. Once the predators run out of food, they start eating each other until the last one simply dies. They won't damage your plants, but there is a balance that has to be maintained much like any garden venture where the predators have to have food - and a continuous food supply to keep protecting, otherwise, they just die off and once they are gone, you get spider mites again.

One last note - you'll need a decent magnifying glass to see anything in detail (like mites eating mites). For the most part, you just get accustomed to what to look for and act accordingly. You WILL be able to see the specks move. You WILL see the webbing, most often at the leaf nodes. You CAN see the specks traveling along the webbing if there are enough of them. You WONT see a spider looking thing with legs and a row of fangs. If you do have access to a 10x or more lens, then you can see them in more detail. Contrarily, they will always just be specks on your plants that eventually kill them if left to run their course.

Two Spotted Spider Mite:

Red Spider Mite:

Wed Jan 11, 2012 6:55 am

Agree, the webbing looks like spider mites to me.

You may even have caught one of the actual mites in one picture. The bottom picture, left hand stem, about the fourth leaf down, on the right side of the stem, there's a little reddish dot in the middle of the leaf. I'm not for sure, but I'm guessing that's one of the mites.

If it is spider mites, a soapy water spray should control them (real soap like Dr. Bronner's, not detergent which can harm your plant).

Wed Jan 11, 2012 5:45 pm

Thank you both very much!

I will try a soapy spray -- good thing I use dr. bronners and dr. woods (a cheaper version of dr. bronners) soaps exclusively, because I have plenty on hand!

Unless anyone can suggest a better method for this, I will try loading a spray bottle with soapy water and spraying the plant down -- perhaps i will try to scrub the webs and what not away first manually.

And finally, should I be concerned that some of the mites may have spread to my other plants which were growing in close proximity to the infected Jade?

Many thanks!!

Wed Jan 11, 2012 5:51 pm

Just be sure to coat the underside of the leaves.

Spider mites do spread. I don't think it would hurt to spray all of your plants in close proximity to the source.