Got Caterpillars? No Worries!

gillnurseryBest Practices, Birds, Butterflies, and Bees, Problem Solving11 Comments

We were watering Pentas earlier this week and came across this funky looking fellow (above). At first, we thought it was a more common Tomato Hornworm, but after doing some research, it’s a Tersa Sphinx (Xylophanes tersa) caterpillar! Actually, both in the photo are Tersa Sphinx caterpillars at different stages. Pretty soon they’ll transform into their beautiful moth form.

Tersa Sphinx moth

Caterpillars have been a big topic of conversation here at Gill’s this Summer; more rain than usual = more caterpillars. A good rule of thumb is to leave them alone unless you see a large congregation and they’re eating enough of a plant to cause harm. A few munched leaves here and there is not a problem. If you do get a large infestation, you can treat with organic Thuricide that only targets caterpillars.

Most different species of caterpillars are only attracted to specific host plants. Pentas are a host plant for the Tersa Sphinx, which was a big clue for identification. We know that Monarch caterpillars like milkweed, Gulf fritillary’s host plant is Passion Vine, and Swallowtail caterpillars like Rue and Dutchman’s Pipe Vine.

Monarch caterpillar
Gulf fritillary caterpillar
Swallowtail caterpillar

Once caterpillars reach their butterfly or moth form, they feed on nectar from a broader variety of South Texas plants like Lantana, Zinnia, Mist flowers, Turk’s Cap, and lots more. So, it’s a good idea to plant host plants and nectar plants together to enjoy the caterpillar’s full life cycle.

-Jesse

11 Comments on “Got Caterpillars? No Worries!”

  1. Help!!! Monarch Caterpillars have eaten the Milkweed to sticks. I have 7 in my kitchen, in a plastic box eating Butternut squash. When do I let then go? When they start climbing to get out? Something has destroyed my Mist Flower, but I don’t care. I worry about my Monarch babies!!! Help!!

  2. The photo labeled Monarch is actually a Queen caterpillar, a close relative of the Monarch – they also eat milkweeds. Thanks for sharing information on caterpillars, raising them is a great project for gardeners, kids, and nature lovers.

  3. I question your statement that monarchs only eat milkweed. I have donated many “non-milkweed” plants to the monarchs and queen butterflies. They love my parsley and devour it every year. I think they eat what is available.

    1. Hi Ann – that’s interesting that they are eating parsley! And you’re right, I shouldn’t have said “only”. Will make that correction.

  4. Thank you for sharing all the info on caterpillars! I began planting milkweed a few years ago for the sole purpose of hosting the monarchs. I love scouring my plants for the eggs, the caterpillars and then searching high and low for the chrysalis and waiting anxiously for the butterflies to emerge. I let them set their chrysalis wherever and it’s always a surprise where I find them if I find them at all. Sometimes I don’t even see them until they have emerged! Great info!

  5. I have three Xylophanes tersa (Sphinx moth) caterpillars who have formed pupae. They have been in the pupal stage for 11 days in soil in a homemade terrarium. Because we’re under a severe heat warning, they are inside at normal room temperature instead of out in the heat. Do you have any idea how long it will take before they emerge? This is a project for me and my children, and we can’t wait to see the adult moths. I’m assuming 3-4 weeks until adults, unless I’m wrong and we will be waiting until spring!

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