suspected russet mite infestation

TechGuy · June 5, 2020

I have been loosing leaves due to brownish curling and drying up. The main stems are brownish.
I have been researching use of wettable sulfur but the bag does not have any application info.

the more I google the more confused I am. I see ... Don't use in hot climate. Don't apply to plants with flowers. Don't spray on melons or cucurbits. Don't apply if oil was used in last month. I have all of these issues.

I am in hot climate, I used neem a couple of weeks ago. I have melons and cukes in next row in high tunnel. My plants are fruiting and flowering and going downhill fast.

With all of these issues I am looking to test a little as I am desperate but I cannot find any application rate ie tablespoons per gallon for example. Any ideas on safe use of this stuff?

Some photos if interested
https://photos.app.goo.gl/wERRXmcrkQt1pJeW7

Barb_FL · June 5, 2020

I really couldn't tell with your pictures but have had Russet Mites in the past. Early on when my plants still looked great, but just stopped setting fruit. They move up your plants.

I check my tomato plants / stems / leaves with a cheap pocket size microscope (<$15 on Amazon). They are really easy to see when they are magnified.

This year, I used Green Cleaner and sprayed my plants before they went out. I have never used wettable sulphur.

Pyganics (another product) will be a knockdown and I think Neem Oil may work if you are persistent in using it - get the adults, get the eggs before they turn into adults and can lay eggs. It won't be easy.

Regular Perthrym should be a knock down also.

There was a good you-tube video geared for weed growers about all the safe products you can use.

You can look up Hemp Russet Mites for info on treatment; maybe they have sulphur listed.

I think your other vegetables will not be affected by RM.

ETA - It looks like you may be out of luck with the Sulphur b/c of previously spraying neem oil, but I just watched a youtube video of using Sulphur for RM, and he uses 1 TBLS per gallon.

TechGuy · June 6, 2020

thanks for your the ideas. I am using jewelers loupe (20x) and can see some tiny elongated shapes so I suspect the mites. I will get a small microscope.

I noticed the russet mites on cannabis says they start at top. all the tomato info says they start at bottom and work up- which is what is happening to me.

I finally found some application rates for wettable powder, One says 3 Tablespoons for gallon and another says 4 T. I am testing out 3 T but I am not sure if I can see it working without microscope.

Barb_FL · June 6, 2020

I think if you can see the RM with your magnifier, that is good enough. The cheapo microscope just gives you light to see so may be slightly easier.

For dosage, that sounds like a lot. I researched last night and saw dosages from 1 TBLS to 2 tsp per gallon.

RM on tomato plants will be the branches above where you can see damage (the brownish glossy look on leaves).

At this point, I think you just have to concerned with how long ago you sprayed Neem oil; that seemed universal.

zipcode · June 8, 2020

That does kinda look like them. I think a great indicator is the fact that the leaflets at the base of the leaf (so towards the stem), are the first affected, and then it moves towards the tip.
The place to look for them is on the yet unnafected ares, upward of where it is affected, they are indeed kinda like a tiny yellowish worm.

Sulfur is such horrible stuff, you will not be able to eat anything from that plant if fruit is touched by it, that is my personal opinion on it. I have used abamectin to stop them at the first sign, nothing else has helped (well, neem helped a bit, but you do need to spray quite often).

mcsee · June 8, 2020

Brown stems are a good indicator something is amiss. If you can get a good magnifying glass or 30x Loupe, you will see them embedded in the stem as a white maggot. Being in Oz I can't recommend any product there that will wipe them out. Something oily will help in the first instance.

TechGuy · June 9, 2020

I have been working with my local ag extension agent who came out yesterday (Monday). She could not see them with her 40x loupe but took them back to the office and put under a microscope and confirmed a heavy infestation.

She recommended the powdered wettable sulfur be sprayed on. I did that last night. I used 4 Tablespoons/ gallon and drenched them. I covered my melons with row covers. I had done a test spray of a few plants a few days earlier of 3T per gallon and the plants seemed to handle it okay.

On Friday, I had done another heavy pruning removing almost all visible signs of damage. By Monday it was pronounced and widespread and required another heave prune to remove before spraying had to be done. Its bad enough that I have a couple of leaders that have no leaves now.

At this point the fruit quality is not up to standard. With heavy pruning and such stress I have mealy, tart flavor, with sun scald from lack of branches above fruit. I have grafted plants so I am in plant saving mode for future harvest at this point.

She recommended in future using predatory mites at first sign in high tunnel but I would have to close it which I don't think is practical due to heat and humidity issues. I do have exhaust fans that I could run but it would still be a lot in hot weather

Here is image she sent me
https://photos.app.goo.gl/QxT1tSqhpVasuegd9

zipcode · June 9, 2020

Predatory mites are supposed to not be that efficient, all I found is that maybe Amblysieus andersoni would be good, but can't find it for sale here (also not cost effective for the few plants I have).
I think predatory mites should be ok to use in an open tunnel, it doesn't have to be closed. Let us know how that sulfur worked.

JosephineRose · June 9, 2020

Pot growers here in California have the same issue. I found a recommendation for using this predator mite.

https://www.arbico-organics.com/prod...er-guide-mites

Important to note: it was also recommended that small flowers like alyssum, gem marigold etc also be planted with the tomato plants to provide nutrition for the predator mite when russet mite populations are low. This mite will stay and get nectar from the flowers apparently.

I am doing this myself this year and plan to release the mite this week.

TechGuy · June 9, 2020

I picked this $14 microscope up on amazon:
https://www.amazon.com/gp/product/B00LAX52IQ

I am not sure it matters too much what type of mite this is, but this is what I got in the HT with the phone awkwardly placed over lens

https://photos.app.goo.gl/bkxLLyxKvGj5a8Gi6
https://photos.app.goo.gl/zDs2bTmuEeR9tRkL8
https://photos.app.goo.gl/F6tPvvbPahmFubsb6

Looks to be broad mites which seem to be more of a pepper problem and not as much mentioned for tomatoes from the searches I have done.

GoDawgs · June 10, 2020

Quote:

Originally Posted by TechGuy

I picked this $14 microscope up on amazon:
https://www.amazon.com/gp/product/B00LAX52IQ

Please let us know how you like this microscope after you use it a while. Looks like something I might want.

Barb_FL · June 12, 2020

That's the same microscope that I have/use. I've had mine since 2016; it's definitely good enough.

On picture 2 & 3, that looks like a RM to me. But definitely not a heavy infestation; unless that was after your treatment.

I hope the sulphur treatment works for you and your tomatoes taste well.

I did Green Cleaner this year that I bought at a local hydro shop ; would not buy from Amazon; actually I don't buy any liquid garden anything from Amazon ; too many broken seals in the past which I can only imagine that the product was diluted.

VC Scott · June 13, 2020

First, starting from the bottom of the plant, remove all foliage that shows the slightest symptoms of infestation. Next, remove the nest higher leaves that do not show signs of infestation. [They are there, you just don't see the damage yet.] Third, spray with food grade diatomacious earth. The ancient diatoms get into the joints of the mites and slows them down. Don't just spray the leaves, spray the stems as well. The little buggers crawl up the stems to the next set of leaves. Spray both top and bottom of leaves. Make that crawl a difficult one. There are some nasty poisons that can slow them down, but I don't like to use them.

Spray DE ASAP because these buggers multiply much faster in the heat. The further you get into summer, the more difficult they are to control.

June 5, 2020	#1
TechGuy Tomatovillian™ Join Date: Mar 2017 Location: Pinehurst North Carolina USA Posts: 31	suspected russet mite infestation I have been loosing leaves due to brownish curling and drying up. The main stems are brownish. I have been researching use of wettable sulfur but the bag does not have any application info. the more I google the more confused I am. I see ... Don't use in hot climate. Don't apply to plants with flowers. Don't spray on melons or cucurbits. Don't apply if oil was used in last month. I have all of these issues. I am in hot climate, I used neem a couple of weeks ago. I have melons and cukes in next row in high tunnel. My plants are fruiting and flowering and going downhill fast. With all of these issues I am looking to test a little as I am desperate but I cannot find any application rate ie tablespoons per gallon for example. Any ideas on safe use of this stuff? Some photos if interested https://photos.app.goo.gl/wERRXmcrkQt1pJeW7

June 5, 2020	#2
Barb_FL Tomatovillian™ Join Date: Apr 2014 Location: Indialantic, Florida Posts: 2,000	I really couldn't tell with your pictures but have had Russet Mites in the past. Early on when my plants still looked great, but just stopped setting fruit. They move up your plants. I check my tomato plants / stems / leaves with a cheap pocket size microscope (<$15 on Amazon). They are really easy to see when they are magnified. This year, I used Green Cleaner and sprayed my plants before they went out. I have never used wettable sulphur. Pyganics (another product) will be a knockdown and I think Neem Oil may work if you are persistent in using it - get the adults, get the eggs before they turn into adults and can lay eggs. It won't be easy. Regular Perthrym should be a knock down also. There was a good you-tube video geared for weed growers about all the safe products you can use. You can look up Hemp Russet Mites for info on treatment; maybe they have sulphur listed. I think your other vegetables will not be affected by RM. ETA - It looks like you may be out of luck with the Sulphur b/c of previously spraying neem oil, but I just watched a youtube video of using Sulphur for RM, and he uses 1 TBLS per gallon. Last edited by Barb_FL; June 5, 2020 at 09:59 PM.

June 6, 2020	#3
TechGuy Tomatovillian™ Join Date: Mar 2017 Location: Pinehurst North Carolina USA Posts: 31	thanks for your the ideas. I am using jewelers loupe (20x) and can see some tiny elongated shapes so I suspect the mites. I will get a small microscope. I noticed the russet mites on cannabis says they start at top. all the tomato info says they start at bottom and work up- which is what is happening to me. I finally found some application rates for wettable powder, One says 3 Tablespoons for gallon and another says 4 T. I am testing out 3 T but I am not sure if I can see it working without microscope.

June 8, 2020	#5
zipcode Tomatovillian™ Join Date: Jun 2010 Location: Romania/Germany , z 4-6 Posts: 1,582	That does kinda look like them. I think a great indicator is the fact that the leaflets at the base of the leaf (so towards the stem), are the first affected, and then it moves towards the tip. The place to look for them is on the yet unnafected ares, upward of where it is affected, they are indeed kinda like a tiny yellowish worm. Sulfur is such horrible stuff, you will not be able to eat anything from that plant if fruit is touched by it, that is my personal opinion on it. I have used abamectin to stop them at the first sign, nothing else has helped (well, neem helped a bit, but you do need to spray quite often).

June 8, 2020	#6
mcsee Tomatovillian™ Join Date: Aug 2007 Location: Victoria. Australia Posts: 543	Brown stems are a good indicator something is amiss. If you can get a good magnifying glass or 30x Loupe, you will see them embedded in the stem as a white maggot. Being in Oz I can't recommend any product there that will wipe them out. Something oily will help in the first instance.

June 9, 2020	#7
TechGuy Tomatovillian™ Join Date: Mar 2017 Location: Pinehurst North Carolina USA Posts: 31	I have been working with my local ag extension agent who came out yesterday (Monday). She could not see them with her 40x loupe but took them back to the office and put under a microscope and confirmed a heavy infestation. She recommended the powdered wettable sulfur be sprayed on. I did that last night. I used 4 Tablespoons/ gallon and drenched them. I covered my melons with row covers. I had done a test spray of a few plants a few days earlier of 3T per gallon and the plants seemed to handle it okay. On Friday, I had done another heavy pruning removing almost all visible signs of damage. By Monday it was pronounced and widespread and required another heave prune to remove before spraying had to be done. Its bad enough that I have a couple of leaders that have no leaves now. At this point the fruit quality is not up to standard. With heavy pruning and such stress I have mealy, tart flavor, with sun scald from lack of branches above fruit. I have grafted plants so I am in plant saving mode for future harvest at this point. She recommended in future using predatory mites at first sign in high tunnel but I would have to close it which I don't think is practical due to heat and humidity issues. I do have exhaust fans that I could run but it would still be a lot in hot weather Here is image she sent me https://photos.app.goo.gl/QxT1tSqhpVasuegd9

June 9, 2020	#9
JosephineRose Tomatovillian™ Join Date: Feb 2016 Location: California Posts: 383	Pot growers here in California have the same issue. I found a recommendation for using this predator mite. https://www.arbico-organics.com/prod...er-guide-mites Important to note: it was also recommended that small flowers like alyssum, gem marigold etc also be planted with the tomato plants to provide nutrition for the predator mite when russet mite populations are low. This mite will stay and get nectar from the flowers apparently. I am doing this myself this year and plan to release the mite this week.

June 12, 2020	#12
Barb_FL Tomatovillian™ Join Date: Apr 2014 Location: Indialantic, Florida Posts: 2,000	That's the same microscope that I have/use. I've had mine since 2016; it's definitely good enough. On picture 2 & 3, that looks like a RM to me. But definitely not a heavy infestation; unless that was after your treatment. I hope the sulphur treatment works for you and your tomatoes taste well. I did Green Cleaner this year that I bought at a local hydro shop ; would not buy from Amazon; actually I don't buy any liquid garden anything from Amazon ; too many broken seals in the past which I can only imagine that the product was diluted.

June 13, 2020	#13
VC Scott Tomatovillian™ Join Date: Dec 2011 Location: San Marcos, CA Posts: 352	First, starting from the bottom of the plant, remove all foliage that shows the slightest symptoms of infestation. Next, remove the nest higher leaves that do not show signs of infestation. [They are there, you just don't see the damage yet.] Third, spray with food grade diatomacious earth. The ancient diatoms get into the joints of the mites and slows them down. Don't just spray the leaves, spray the stems as well. The little buggers crawl up the stems to the next set of leaves. Spray both top and bottom of leaves. Make that crawl a difficult one. There are some nasty poisons that can slow them down, but I don't like to use them. Spray DE ASAP because these buggers multiply much faster in the heat. The further you get into summer, the more difficult they are to control.