Scientist in the garden: tomato crop builds, faces giant enemy

As regular readers of this blog know, one of my hobbies is gardening and I like to bring a scientific perspective to the garden. This year in my garden I’ve planted a whole bunch of tomatoes including unusual and fun varieties. Little did I know that a giant tomato enemy would arrive. More on that in a bit.

Below is a plate of the ones I picked today including the blue one Dark Galaxy and the funny pointy-tipped yellow cherry ones called Barry’s Crazy Clusters, which in both cases are from Wild Boar Farms, a local place known for creating amazing new tomatoes (@WildBoarFarms). Note that big Celebrity tomato on the right that weighed nearly a pound.

Paul's tomatoes

Returning from the big ISSCR stem cell meeting in SFO I found my vegetable garden doing pretty well despite the constant near-100 degree temps we’ve had in the Sacramento-Davis area for weeks. The heat has been nearly unrelenting and remarkably both on the way to and from San Francisco there were two brush fires going both directions that mucked up traffic. This doesn’t bode well for the fire season.

Giant tomato hornworm

My tomato plants looked a bit thirsty despite sprinklers and some watering by the family, but pretty good overall. However, while watering I did find one tall plant that had nearly all of its leaves missing right from the top.

My first thought was, “Oh, no, must be a giant tomato hornworm!” It didn’t take long to find the massive beast that had been gorging itself on this plant (see image above).

One of the most striking things about these caterpillars is their spine on their rear end and this guy’s was bright red. This particular monster was longer and wider than my pointer finger. No wonder that plant was half-stripped of its leaves.

Rather than kill it, we decided to capture and study this thing for a while. I don’t know if it will turn into a giant five-spotted hawk moth before we lose patience with having it in the house in a huge jar with tomato leaves for food.

I found another tomato plant with some moderate damage, but by the time I noticed it the much smaller hornworm that had been munching on it was itself becoming a snack for a wasp. I’m no fan of hornworms but felt a bit of sympathy for this one as the wasp literally carved out chunks of it and flew off with them. Other kinds of wasps can lay eggs on the hornworms, which later leads to more carnage upon hatching. It’s a jungle out there in the garden.

I’m hoping the tomato bumper crop continues, but mother nature is turning up the heat further the next 4-5 days with a series of triple digit days so that could make the plants more stressed.

11 thoughts on “Scientist in the garden: tomato crop builds, faces giant enemy


  1. Paul – You get kudos from me for sparing the tomato worm. Would it perhaps like a bit of the actual tomato as well as the leaves? Maybe, if you cut out the core, you could try it. I am no longer able to garden, but even when I could, I never was able to grow beauties like the ones you are growing. They are beautiful. Nothing tastier than a garden fresh tomato in my opinion.


  2. We used to dissect those horrid things in biology! Back in another lifetime and state, I had a garden of GREAT tomatoes..until I went out one morning to pick some and found two that showed traces of chewing. And found a three inch, very thick creature, having a satisfying breakfast on a third. After I screamed, I gingerly picked it off and threw it in the creek. Not like yours and a subtle green. Any ideas what it might have been?


    • Hi Jeanne, Yeah BT is good stuff and organic, but so far the damage is limited to a couple plants and the wasps around here seem to have been eating a lot of these guys when they are little. I was curious if a bird might have eaten this big guy if we didn’t pull him off, but he blended in so well maybe not. Paul


  3. @Barbara, I didn’t want this giant to eat my tomato plants but didn’t want to kill it so we for the moment have kind of adopted it. Some years the tomato crop doesn’t go so well, but this year it is better, which is fun. Paul


  4. @Lynn, It might have been a hornworm. They get really big and vary in color or it could have been some other kind of caterpillar.


  5. Lynn, you were brave to pick up the creature and throw it in the creek. Keep an eye out for his friends who may want to ruin your tomatoes.

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