Tomato Russet Mite, oh my!

There is a plague in the Bay Area, and it might be affecting you and your tomato plants - the Tomato Russet Mite.  We have gotten a lot of emails from tomato growers in California complaining  of symptoms congruent with this pest, so if your tomato plants are affected, you're not alone!

The major symptom of TRM is the yellowing and eventual browning (death) of leaves.  Leaves near the bottom of the plant are affected first, and the mites work their way up the plant as they desiccate it.  It only takes a couple of days of infestation for this pest to do irreparable damage to your tomato patch, so hurry!

The Tomato Russet Mite is a pest that is impossible to see with the naked eye.  If you are worried that your plants are infested with the TRM, go to your local nursery and get a 20x (at least) hand lens and inspect your plant's foliage.  These pests are cigar shaped and have two sets of legs.  These guys reproduce like wildfire, newly hatched larva begin laying their own eggs in 48 hours, so it's imperative to get a handle on this as soon as you notice damage. The highest concentration of TRM will be just ahead of the most affected area, so don't only look at the damaged leaves.

These mites also affect other members of the Solanaceae family, so check your eggplant, pepper plants, ground cherries, tomatillos and potatoes.  Even if they are not affected, it's a good idea to do a preemptive treatment anyway, especially if you've noticed quick-moving damage.

The best way to treat your affected plants (and those that you are preemptively-striking) is to use a miticide (like an insecticide, but more specific).  A good one is Azatrol, available at most hydroponic stores, or here.   Take care to cover the entire plant, coating the tops and undersides of leaves is key to control.  If you can't find Azatrol, look at the pesticides in your local nursery to find one that is effective against mites.  As always, don't spray when bees are out foraging or about to start foraging.   

Good luck, and act fast!

 

Comments

[carolyn krchmar]

Thanks for this post Cynthia, my plot in the community garden was inspected by some local master gardeners and they confirmed Russett mites. This was a few days after I had sprayed with a miticide from Bonide since I wasn't able to find the Azatrol. I think my plants are on their last legs for this season so I will add it to my arsenal fro next year. BTW, the Love Apple variety I bought from you did quite well.

[Love Apple Farm]

Cyndy: Azatrol is a certified organic miticide. Just as anything else in life, use protection! If you need to protect yourself from a sharp knife, you do it! How else are you gonna cut a steak? Our government demands that warning labels are on EVERYTHING. At some point, it becomes ridiculous.

Having said that, if you've got mites, then you need to bring out as heavy of a gun as you can get away with. Neem oil is fine, but it ain't gonna kill all those mites as fast as they need killin.'

Let's say this: your femoral artery is cut. You either bleed out immediately, or you apply a tourniquet and get yourself to the hospital. With Neem, you're applying a band-aid. It's good for less destructive pests, or as a prophylactic, but not if your plants actually have the dreaded mite.

[Cyndy Shafer]

Hi Cynthia...I've taken your tomato classes in recent years. I think we may have tomato russet mite on our plants up here in Petaluma. I bought the Azatrol, but in reading the label, I'm concerned about the potential health effects to me during application...they make it very clear to use all PPE and to call a poison center or doctor if you even get it on your skin! My question: I also have Neem oil... Will Neem oil stop the tomato russet mites as well?

[Love Apple Farm]

Gary: I would spray those plants with either Azatrol or Neem Oil, to be on the safe side.

[Gary Neier]

Thank you for the article, and the advice. I'm not sure if I have mites or not. For the last month or more 3 of the 5 tomatoes I bought from LAF have been been having trouble in the lower half. I assume its the varieties not liking the constant fog (am in western santa cruz, near coast).. Reading the article and comments again, I don't think I have mites but want to check and share a picture of one plant. http://yfrog.com/12img1502yj What do you think?

[carolyn krchmar]

Thanks Cynthia, Last year I had an incredible harvest from your plants. Couldn't figure out how my luck changed so quickly, I planted cover crops over the winter, built a dozen 7 ft tall cages,planted per your directions with fish heads and everything. I chalked the dying plants up to gophers tunneling underneath, a super windy spring, followed by a cool summer, my plants may be toast but you give me hope for next year! Thanks for the encouragement, going to look for Azatrol on my lunch hour!

[Mary Ellen Cuykendall]

Turns out I had the same mites last year and thought it was a water issue or something in the soil. Moved my plants to a completely different spot in the garden this year and am now seeing the signs on my Sungold plant as well as others. Thanks for sharing the info!

[Love Apple Farm]

Jim: Yes, the spray can safely be used with fruit on the plant. Curiously, Tomato Russet Mites don't tend to do their awful damage on plants that have no fruit (they wait until after fruit set - don't know why). Hence, the gardener HAS to spray while there are fruit. Azatrol is organic and approved by OMRI. Ya better hurry!

[Jim Amato]

I too have been struck, so far have lost 5 tomato plants and am worried about the rest of my garden. Can the spray you mention be used right now with fruit on the plants? Will it harm the fruit or the fruit consumer?

[Kathleen Dettman]

Thanks so much for the timely advice. I have been experiencing similar problems - and at first thought my tomato plants were not getting watered properly. I was beginning to suspect some sort of root borne pest and was about to email you to ask your advice. The mites might also explain some of the less than vigorous plants I have had in the past (although they always seem to bear fruit). I like earlier posts am interested in preventive measure for next year.

[Ron and Lindsay]

We appreciate your updates of garden info as we are experiencing tomato mites in our garden that started with our Sun Golds.
Thanks again.

[yvonne]

Thanks for the update, I took some serious hits to my plants this year. Some plants survived but the mites continue to threaten. I'll try the Azatrol. Anything else for next year? I am wondering if they will overwinter in soil or debris and I should try solarizing the soil next year or just preventative spray.

[Karen W]

I have a Japanese Black Trifele which has started to look unhealthy. I'll check for these mites in the morning. Thanks for the info!

[Steve Kay]

Always a source of great advice. Thanks for this. I'm going out to check tommorrow morning.

[Stephanie C.]

I was wondering what was going on with my tomato plants this year. I thought it had something to do with the cool weather, but it sounds like Russell mites might be exactly my problem. Thanks for the info!

[Jackie]

Thank you for the heads-up. I'm going to check my plants ASAP!