Nocturnal tomato pest

Asked July 23, 2020, 7:00 PM EDT

Can I spray a home made mix of water, eucalyptus oil, oregano oil, tea tree oil, lemon grass oil ON the tomato plant? i use it for biting insect/spider repellent but have been careful to avoid the tomatoes. Insect eating tomato plant leaves at night. leaving piles of little black poops the size of a large pin head on the leaves below where the leaf has been eaten. have not seen the insect in the daytime. no worms, eggs, on under sides of leaves. two plants. both same variety Celebrity. only one plant is affected. Saw a light colored miller on the soil shortly after sundown and removed it. After that, damage started. half a dozen wasps are now swarming the same plant in the afternoon sun. tomatoes are growing in large pots on third floor deck. Every year for over ten years. Pots are cleaned in bleach water and filled with new soil each year.

Hennepin County Minnesota

5 Responses

I am part of Extension so I can’t recommend an untested or reviewed pest concoction. I can’t find any I formation about it nor am I familiar with it. There is no way to evaluate effectiveness or affect on the plant. If tomatoes are getting plants of water they can usually keep ahead of pests.

Your plant may have flea beetles. It would be something to look for. The miller moth doesn’t eat tomato plants.

My goodness. Blah blah blah How many years have you grown tomatoes?

Already checked the website you referred me to. Was frustrated with so little tomato information. Thus the message.

Not flea beetles. Nothing close to that. Doesn't look anything like the damage in the photo. Eating whole leaves overnight. Then disappears in the day. We sit on the deck several hours a day between 3-4 feet away and check the plants a dozen times per day.

Water not an issue.

FYI I put a fine mist of the essential oil mix (heavily watered down) over the plant and inside. Very light. Did not drip off the leaves. Nocturnal damage stopped. Wasps were no longer attracted in the day. Plants thriving other than losing 3-5 leaves.. We can sit on the deck again.

Sorry to waste your time. Not inclined to seek extension advice in future.


Your first response to my question appeared to be online search results (which I had already done at various sites) and not from experience. The negative, robotic reply did not inspire confidence in U of M Extension, basic customer service skills or an earnest desire to share with a fellow gardener.

i couldn't get past these:
Not my job, I can't, I can't, there is no way.

Thus the frustration in my first reply. That was not my best moment. I should have given you specific feedback the first time; a better way to say your words and tone were not helpful.

Also, I received the third email you sent privately, not visible on this thread. It negates "Have a nice day". Perhaps you regret sending it?

Please don't send privately again.

I'm sorry if you've found your experience with University of Minnesota Extension Master Gardeners has not met your needs. We are unpaid volunteers and we dedicate our time to answering all manner of gardening questions from the public, with answers that are based on current peer-reviewed University research.

We never send replies privately. Perhaps you received a reminder through the system that you had a response to your question (as you will for this response).

The person who answered your question has many years of experience growing tomatoes. I, myself, have grown tomatoes for over 50 years. The mixture you are using is not research-based. We cannot recommend either its efficacy or its safety.

As for what is damaging your tomato's leaves, you could look at night with a flashlight when you say the damage is happening. You could also send us a photo of the damage and the excrement. One pest that eats tomato plants is the tomato hornworm. In spite of its immense size, it is easy to miss because it blends in with the foliage. It will leave black excrement like you've described. However, tomato hornworms are not common in Minnesota.

Some other possibilities are slugs (feed at night, but not usually on tomatoes, and don't leave excrement) or some critter (squirrels, birds).