How can I prevent an hornworm attach? Does planting borage or peppermint help?

Thanks

Look for the eggs. Remove the eggs before they hatch. If the eggs hatch, use something like Bt or spinosad per the label to kill the caterpillars. In my experience, these extracts will absolutely eliminate current hornworm infestations, but won’t prevent future infestations.

Netting will help as well.
The darned things seem to grow overnight.

hunt them down after dark with a black light

Move to SW Idaho. I saw a hornworm here once, as a child. I thought it was awesome. I do see big moths that in theory could come from hornworms (they love Phlox), but I don't see the actual caterpillars anywhere, and we grow lots of tomatoes. Maybe it's just my garden.

Seriously, though, you probably don't want to move here just to grow tomatoes (you'd have to learn how to tomato garden all over again, and you might end up getting hornworms anyway).

I've been planting basil with my tomatoes on the end of rows and haven't seen any hornworms.
https://www.backyardboss.net/plants-tha ... -tomatoes/

Nothing to add on preventing them, only had an issue once. Just wanted to share my picture

Keep a daily watch out for their poop which is almost pea size and pick them off.

Shule wrote: ↑Mon Mar 24, 2025 7:42 pm Move to SW Idaho. I saw a hornworm here once, as a child. I thought it was awesome. I do see big moths that in theory could come from hornworms (they love Phlox), but I don't see the actual caterpillars anywhere, and we grow lots of tomatoes. Maybe it's just my garden.

Seriously, though, you probably don't want to move here just to grow tomatoes (you'd have to learn how to tomato garden all over again, and you might end up getting hornworms anyway).

Shule the moths that you are most likely seeing are the white-lined sphynx moth or the P. Modesta. Neither of these would be feeding in your garden other than to use flowers for nectar.

karstopography wrote: ↑Mon Mar 24, 2025 6:02 pm Look for the eggs. Remove the eggs before they hatch. If the eggs hatch, use something like Bt or spinosad per the label to kill the caterpillars. In my experience, these extracts will absolutely eliminate current hornworm infestations, but won’t prevent future infestations.

I agree. I've never used spinosad but the bT works wonders. Around here the hornworms usually show up in June so in late May I usually do a bT application on the tomatoes and that seems to work pretty well. When one finally does show up later, one more app usually takes care of it for the season.

Each horn worm has its plant that it eats more or less.
We have one that eats a wild vine down here doesn't bother anything else.

Here's the difference between the tobacco hornworm and the tomato hornworm.

Only one we get on the tomatoes or peppers here are the Tobacco Hornworms. Never seen a Tomato Hornworm.

That's all I've ever seen as well.
The dreaded tobacco hornworm on tomato plants.

tyrupp wrote: ↑Mon Mar 24, 2025 7:18 pm hunt them down after dark with a black light

That is what I do. It's easy and cheap. They glow green under a black (UV) light, making them easy to spot at night, which is when they are active. This is because their skin contains certain pigments that fluoresce when exposed to UV light.

Here's how it works:

UV Light: Tomato hornworms, like many caterpillars, have pigments in their skin that absorb UV light and re-emit it as visible light (fluorescence).

Glowing Effect: This fluorescence makes them appear to glow green or white under a black light, especially against the dark green foliage of tomato plants.

Handheld UV lights are something like: https://www.amazon.com/Flashlight-Vansk ... UG2?sr=8-1

JerryHaskins wrote: ↑Fri May 23, 2025 9:13 am

tyrupp wrote: ↑Mon Mar 24, 2025 7:18 pm hunt them down after dark with a black light

That is what I do. It's easy and cheap. They glow green under a black (UV) light, making them easy to spot at night, which is when they are active. This is because their skin contains certain pigments that fluoresce when exposed to UV light.

Handheld UV lights are something like: https://www.amazon.com/Flashlight-Vansk ... UG2?sr=8-1

Thanks for the link. I just added one of those to an Amazon order I was going to send in tomorrow.

@JerryHaskins , thanks for that link to the flashlight! I ordered one and it arrived yesterday. I used it last night and so far so good. No hornworms! I think I'll wait until I see some caterpillar poop before I use it again. It sure will save time.

I see that an upgraded version is available for more money but I think the $10 one I got will work just fine.