The stems of my tomato plant has some brown/rusty markings on them. They appear to be deep and some are deeper than others. The fruit seems to be doing ok. Any ideas of what this could be and could it spread to my other plants? Thank you!
Certified GKH Gardening Expert
This looks to me like an insect, worm or caterpillar damage. It doesn't appear to be a disease; bacterial or fungal issue.
Inspect the plant for any pests that may be hiding under leaves.
I would spray the plants with Neem Oil. Neem Oil is organic and works as both an insecticide and fungicide.
It is safe for people, pets and Bees.
Here are some articles that may help with things to watch for.