Tomato Horn Worm

Manduca quinquemaculata

Tomato Horn Worms are very hard to see as they hang in the shade underneath foliage. But this one, covered with white cocoons of the predatory Braconid Wasp,
is easily seen against a background of ripe tomatoes.

Also seen to the left, is its ornamental yellowish tail "horn", from which it gets its name. If allowed to mature, the Horn Worms may exceed 3" in length.

It's very difficult to find the two Horn Worms in the top of this photo.
It's much easier to spot evidence of their presence in the bottom 3 photos:

On the left are dark green pellets indicating that there was a Hornworm above.
In the middle is a stem missing some leaves; another Smoking Gun.
On the right is a wilted leaf hanging by a nipped stem, which leads the eye

to the white Cocoons and their otherwise camouflaged host nearby.

Leaves are their normal fare, but this Tomato Worm was caught munching on a Green Tomato. Even though it looks healthy, it may be doomed by Wasp Eggs already laid in it.

It must continue to eat if any Wasp Larvae inside it are to mature and come out to spin cocoons. But it will never spin its own cocoon to become a winged adult and lay eggs to propagate its species in your Garden.

In this photo, just to the right of the bottom Wasp, can be seen the dark half-moon of a Wasp nearly chewed free. And just below the same Wasp, can be seen the dark head of a Wasp through the translucent end of its cocoon.

I noticed two individual Wasps get separate but identical reactions from the Worm when they took flight from its "Horn". As they crawled up to the tip of the Horn, the Worm made a sideways thrash of its head, that in a split second formed its body into a horseshoe. It appeared that the Horn was extremely sensitive.
I marveled that this undermined victim had the power to perform this motion.

These two Horn Worms are in the final stages of predation. At left is a dead specimen which is turning brown. On the right can be seen open-ended cocoons, indicating that their 1/4" occupants have emerged and flown away to mate and victimize more Tomato Horn Worms. The microscopic exit holes made by the emerging larvae, can be seen on both Worms.

The mature Caterpillar bores into the soil to complete its life cycle.

If you remove the Horn Worms with attached Cocoons, and put them in a glass jar with no lid, they will die. But the predatory Wasps will emerge and fly away to prey on other Horn worms in your Garden.

Beverly W.
Master Gardener