Is there someone who an help me diagnose a problem with tomatoes? I've been growing tomatoes in a high tunnel for 10 years. It has been successful fo...
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Tomato Deformity #877351
Asked July 15, 2024, 4:12 PM EDT
Is there someone who an help me diagnose a problem with tomatoes? I've been growing tomatoes in a high tunnel for 10 years. It has been successful for 9 years, but this year all 30 tomatoes plants are diseased. I'm growing Sakura cherry tomatoes and heirloom Cherokee Purple tomatoes, both varieties which have done well in the past. They were doing well at first, but then the upper leaves began to curl upward. It started on the Cherokee Purple and soon spread to the Sakuras. I read that upward curling leaves could be caused by too little water, so we upped the drip irrigation and at one point saturated the beds with buckets of water. As the weeks progressed the new growth has become more and more deformed. I've included photos. The first photo shows the initial upward curling leaves. The second and third photo are of the middle and top portions. Can anyone tell me what the problem is? Is there anything I can do? There is some fruit on the vines, so hopefully I don't need to destroy them entirely.
Kenai Peninsula CountyAlaska
Expert Response
The symptoms on your tomatoes look like either a virus disease or herbicide damage. Since all or most plants are affected, it is likely not a virus. Sometimes a virus can be transmitted with the seed and a plant is looking "strange" like the pictures, while the rest of the plants are doing well.
Tomatoes are "hypersensitive" to herbicides. Is there any chance, a herbicide like 2,4-D was used and sprayed in the vicinity of the greenhouse? Could there have been some wind drift during an application from neighboring lawns or ag fields? It could maybe also have come in with mulch or compost. Herbicides may have been on the plant material and not completely broken down in a composting process.
Wish I had a good answer and solution, but unfortunately, I don't think there is much hope for these plants. If you are able to harvest some tomatoes, they are still safe to eat.
Thank you for your reply. Herbicide damage is very unlikely. We never use herbicides, nor does the neighboring rancher. Our neighbors could have used small amounts in their yards, but our high tunnel is pretty far from any other houses. There is a possibility that the hay we purchase for our goats has been sprayed with herbicide, and that it didn't break down in the compost. We slow compost all of their bedding for 3 years before using it. But nothing else we used this batch of compost on has shown any ill effects. Is there a lab that can test for herbicide residue?
Is there a way to test for virus? I'm suspicious of virus, since it started with the Cherokee Purple tomato that I started from seed purchased this year. It then quickly spread to the rest of the Sakura tomatoes. As you say, it might have come in with the seeds.
Thank you for the update and additional information. I agree that it is unlikely to be herbicide damage, since it has been spreading among the tomato plants.
You can test for viruses but there are many different viruses to test for. Since it has been spreading, I am wondering if you have seen any insects around the plants like thrips or leafhoppers? They are vectors and can carry virus from one plant to another.
Here is an update - I showed the pictures to our plant pathologist Dr. Jenifer McBeath. Her immediate response was that this is herbicide damage (like 2-4D or similar compounds). It is not a disease or pest problem.
She said that the most common entry way for herbicide contamination is now through compost. You can try increasing air moment through the high tunnel and around the plants to limit the damage. If you have other plants in the high tunnel, they may not be affected since tomatoes are more sensitive to herbicides than any other plant.
At the link below is a publication from Montana State University about herbicide contaminated soils and amendments. They recommend doing a bioassay to check if the compost is contaminated with herbicide.
Thank you for the information. We are doing the MSU bioassay test on tomatoes and peas. So far, both plants grown in Alaska Earth potting soil and soil from the high tunnel beds are doing well.
Is there any possibility that damage from soil salinity could appear similar to damage from herbicide residue? My soil test from fall 2022 indicated rising salinity levels. We're proceeding with repeated flooding of the high tunnel beds. The soil test recommendation was for a total of 12" of water. That translates to 4.7 gallons per square foot. So far they've gotten about half of that amount. The tomatoes are looking a bit better. Some of the gnarled looking upper leaves are opening up onto normal looking leaves. The lower fruits are doing well. The upper fruits are long and pointy rather than round. So things are still weird.
I think this might also explain the stunted winter squash and cucumber plants in the high tunnel, as they are also susceptible to herbicides.
Does flooding wash out any herbicide residue? We'll apply biochar in the fall, per the MSU publication you referenced. Do you have a recommendation on the amount per square foot?
One last question, do you have any references about herbicide use on hay fields in Alaska? I can ask individual farmers about what they're using on the hay I buy, but I was wondering if there was some general information about what farmers are using. Our compost is made from goat and chicken bedding containing hay. The compost that we applied last fall was from brome hay purchased in 2020 from the DeVilbis farm in the Palmer area. Whenever available, we're now buying brome hay from Triple Cross Ranch in the Delta area.
Good questions. The high soil salinity may have contributed, but the symptoms of herbicide damage are very specific. High salinity usually results in overall stunted and poor growth. Flushing the soil to reduce salinity is a good idea in preparation for next season. Not sure if it will flush out any of the herbicides.
The rate I have heard for biochar is about one quart of crushed biochar per sq foot to be mixed into the top 4 inches of the soil.
I doubt there is any references or information on the use of herbicides in Alaska for hay or other crops. Most farmers are really trying to get away from using herbicides. If they find it necessary, herbicides are likely only used as spot treatment on particularly difficult areas or weeds. Asking the farmers about any use of herbicides is likely your best option.
