All my tomatoes in my cattle panel hoophouse have white leaves on the top of my plants. Looks like only the small young leaves are affected. What is causing this? These plants are under a 40% shade cloth so I doubt its sunscald. It looks exactly like herbicide damage but I haven't sprayed any herbicide this year. I had the same thing happen early this spring and figured it could be broad mites since I've read they can cause herbicide-like symptoms but I've read broad mites can't reproduce in temperatures over 93 degrees and we've 2 straight months of 100+ degrees here.

Anyone have a suggestion?

Sounds like mites.

Spider mites suck out the chlorafil but they leave white spotting not totally uniform white leaves. Ask me how I know lol.

Using any kind of mulch that may contain herbicide residue?

Have you gotten out a magnifying glass and checked for mites?

Uncle_Feist wrote: ↑Sat Aug 06, 2022 7:50 pm Using any kind of mulch that may contain herbicide residue?

Zero mulch. These tomatoes are in 12 gallon containers.

MissS wrote: ↑Sat Aug 06, 2022 8:07 pm Have you gotten out a magnifying glass and checked for mites?

I don't have a microscope. However outside of broad mites, I can't think of anything else it could be. Plants looked perfect a few days ago.

Do not confuse broad mite injury with herbicide injury, nutritional (boron) deficiencies or physiological disorders.
https://www.greenhousemag.com/article/g ... ble-pests/

However, the University of Georgia says this:

Broad mites have a wide host range and can occur throughout the year in tropical climates. Reproduction does not occur below 55 degrees nor above 93 degrees. Temperatures of about 77 degrees and humid conditions are most favorable. Cold winters and hot, dry summers usually limit
populations in Georgia. Rainy fall seasons provide optimal conditions for broad mites in south Georgia, and the greatest damage usually occurs at these times.
https://extension.uga.edu/content/dam/e ... d_mite.pdf

The AVERAGE temperature here in San Antonio has been over 100 degrees since 1 June and we haven't had any appreciable rain since May.

Maybe the 40% shade cloth keeps it cool enough for them??

I have been operating under the assumption I have broad nites so I sprayed for mites the day after I saw the first white leaf. I had the same problem this spring. Sprayed permethrin and neem on alternate days and dusted with diatamaceous earth. That didn't work at all so I sprayed with ivermectin this time.

I only got 2 weeks of tomatoes this spring because of the heat and now my Fall tomatoes might be toast.

Spider mites (I don't know about broad mites) make very small marks, in large numbers, which make the leaves and/or fruit look stonewashed (similar to leafhopper damage). I wouldn't describe the damage as white, personally; just stonewashed (more of a pattern than a color; the damage is too fine to really say it's white, IMO).

It might be thrips you're dealing with, which can make larger, obviously white, marks that are spaced further apart. Do you have a picture? Any TSWV in your garden, this year, by chance? (Thrips can spread it.)

In hotter temperatures, I notice more thrip damage in the shade.

Ivermectin as a tomato plant spray? I have never heard of that since it is a medication for parasitic worms.

brownrexx wrote: ↑Sun Aug 07, 2022 8:32 am Ivermectin as a tomato plant spray? I have never heard of that since it is a medication for parasitic worms.

This is my first time experimenting with ivermectin. I read about ivermectin on some marijuana forums where several high profile growers claimed it completely wiped out mites in 1 spray. When you do a little research, it does make sense. Ivermectin and Abamectin are both fermentation byproducts of Streptomyces avermitilis, a soil actinomycete. Abamectin, the active ingredient in Sygenta's AgriMek miticide, is considered the best miticide by marijuana growers. However AgriMek can only be purchased in bulk from authorized agents. So unless you'll willing to cough up $$$$$, forget about it. Ivermectin horse paste (apple flavored!) cost $6 at Tractor Supply.

Obviously ivermectin is not labeled for use on tomatoes but since people are prescribed 3 gram invermectin pills (Brand name: Stromectol), I can't see how this could be a problem especially at the 1 gram/gallon concentration sprayed.

Sygenta also makes a product called Avid which contains a lower % of abamectin. It's labeled here in the US for use against ornamental plants only. However, the New Zealand branch of Sygenta actively markets Avid as a vegetable garden spray.

https://www.syngenta-us.com/insecticides/agri-mek-sc

https://www.syngenta.co.nz/product/crop ... icide/avid

Shule wrote: ↑Sat Aug 06, 2022 11:54 pm Spider mites (I don't know about broad mites) make very small marks, in large numbers, which make the leaves and/or fruit look stonewashed (similar to leafhopper damage). I wouldn't describe the damage as white, personally; just stonewashed (more of a pattern than a color; the damage is too fine to really say it's white, IMO).

It might be thrips you're dealing with, which can make larger, obviously white, marks that are spaced further apart. Do you have a picture? Any TSWV in your garden, this year, by chance? (Thrips can spread it.)

In hotter temperatures, I notice more thrip damage in the shade.

I took some photos with my iPhone yesterday but I don't think I have a way to post them here. Walter Reeves has a photo on his website that look similar to some of my plants.

https://www.walterreeves.com/food-garde ... up-damage/

I've dealt with thrips, aphids, and TSWV before so I don't think any of those are the problem. With the blazing prolonged heat here this summer, there are absolutely zero thrips/aphids I see anywhere. Never seen anything like it.

I'm starting to think I may have gotten some herbicide drift from some neighbor?!?!

Marijuana growers consider Avid highly toxic and only use it as a last resort. It sounds like Syngenta has a corrupt connection in NZ government if they tell anyone Avid is safe.

@Wildcat82 Glyphosate is a good possibility especially with you saying that they had this when they were young and then now again for now an unexplained reason. Are you getting any distortion on your leaves?

Cole_Robbie wrote: ↑Sun Aug 07, 2022 11:59 am Marijuana growers consider Avid highly toxic and only use it as a last resort. It sounds like Syngenta has a corrupt connection in NZ government if they tell anyone Avid is safe.

There may be other variables in play as well besides corruption. For example, the exposure pathway is different i.e. smoking marijuana versus consumption of vegetables. Smoking anything creates combustion byproducts. For example, burning plastic creates some really horrible byproducts you should never breathe (ask the Army about its open burn pits in Iraq) whereas eating a piece of the same plastic will not be digested at all and pass through the body harmlessly.

There may also be standards for insecticide residual so the growers might be mindful of that if they want to sell their product. This is like when cattle are taken to slaughter they are tested for antibiotics/insecticides so feedlot operators know they have to wait a certain period of time til these substances fall within standards.

Further, Avid may be toxic or it may be completely safe in the doses used. I haven't seen any studies.

On the other I wouldn't be surprised anything Sygenta (or Monsanto) would do to get their product approved.

MissS wrote: ↑Sun Aug 07, 2022 12:22 pm @Wildcat82 Glyphosate is a good possibility especially with you saying that they had this when they were young and then now again for now an unexplained reason. Are you getting any distortion on your leaves?

This spring I had 6 tomatoes in 3 straw bales on the east side of my house. Three of the 6 developed herbicide type damage and were pulled after a couple weeks. I couldn't tell if broad mites or herbicide caused the problem though I tend to think the straw bales were contaminated. My cattle panel hoophouse in on the other side of my house.

I don't see any distortion of the leaves.

I am dealing with Glyphosate issues this year. My plants have a mild dose and have distorted foliage on new growth but they work out of it as the leaves age at least on most of the plants. I have had foliage sprayed with it before and the leaves did turn white so perhaps this is your issue. Have you talked to your neighbors to see if they have sprayed anything?

Herbicides can drift very far if sprayed on a breezy day and it doesn't take much to affect tomato plants. They are very sensitive to it.

Shule wrote: ↑Sat Aug 06, 2022 11:54 pm Spider mites make very small marks, in large numbers, which make the leaves and/or fruit look stonewashed (similar to leafhopper damage). I wouldn't describe the damage as white, personally; just stonewashed (more of a pattern than a color; the damage is too fine to really say it's white, IMO).

Thank you for this, I had started a thread about my ground cherries ( ground-cherry-leaf-problems-t3631.html ), and later in the season (now) the leaves start to get that "stonewashed" appearance. I never thought I had mites of any kind, but I took a leaf inside (which had the telltale webbing around the edge) and saw something moving under my magnifier, so I borrowed a microscope and positively identified a spider mite. I'm not sure if the large white spots earlier in the season were from the spider mites, or thrips, as you mentioned, or something else, but now that I know I can/do get spider mites, I will take proactive steps in the future (seasons); I just sprayed some PureCrop1 on my ground cherries, we'll see if that helps...the plants are pretty bad between the hot dry weather and whatever else is going on.

MissS wrote: ↑Sun Aug 07, 2022 4:12 pm I am dealing with Glyphosate issues this year. My plants have a mild dose and have distorted foliage on new growth but they work out of it as the leaves age at least on most of the plants. I have had foliage sprayed with it before and the leaves did turn white so perhaps this is your issue. Have you talked to your neighbors to see if they have sprayed anything?

Assuming I have herbicide damage, I can think of few possibilities.
My neighbors have a lawn service and I don't know what they spray (my neighbor has no idea what the service does). It's possible they sprayed something and it drifted over the fence.

My pump sprayer went bad so I used an old sprayer I had in my shed that I hadn't used in a few years. I'm always very careful to use a permanent marker to indicate if a spray pump has ever sprayed any kind of herbicide so I don't mistakenly use it on my garden. The older sprayer I used was not marked. Unfortunately that sprayer developed a clogged nozzle so I tossed it and bought a new one. If I still had the old sprayer, I could have tested it to see if there was any herbicide residue.

I vaguely remember my wife spraying something a few years ago (she doesn't remember). I'm guessing she didn't triple rinse, clean out he nozzle, or use a permanent marker. I'm kinda leaning to this version.