Braconidae (Cotesia congregatus)
The Braconidae are a family of parasitoid wasps, the second largest family in the order Hymenoptera with approximaely 17,000 recognized species and many thousands more that are undescribed. Source: Wikipedia
Scientific name: Braconidae
Higher classification: Ichneumonoidea
These beneficial Parasitic Braconid wasps are found throughout North America and preys on horn worms and other garden pests; hunting them down and injecting their eggs into the pests where the eggs hatch into larvae and will begin eating the internal organs of their new host. There are several species, over 2,000 species in just North American; most species are less than half of an inch long.
The female wasps lays her eggs under the skin of the host. Once matured they bore through the worm’s skin, spin a cocoon and attach themselves to the worm. The larvae feeds inside the caterpillar; when fully grown, they chew their way out of the host’s body. The cocoons then emerge as adult Braconid Wasps that will start hunting for pests to continue the life cycle.
These wasps won’t sting humans unless they are provoked.
What to do:
If you see any horn worms or other insects in your garden, by all means remove them. If they have these white pods on them, let the host live so the wasps can do their job. They are creating a new colony of soldiers to defend your plants from ‘bad’ insects in your garden.
While the life cycles of these parasites and their hosts are closely synchronized, the wasp larvae may not kill their hosts for a long period, however they are lethal to the host.
Once outside, they spin their own tiny oval cocoons that look like large grains of rice on the back or sides of the horn worm. Tiny adult wasps eventually emerge from the cocoons and seek out new horn worm hosts.
My Personal Experience With This Beneficial Insect:
I purchased predator wasps that came as cocoons; they were very expensive and half the cocoons didn’t hatch. I didn’t see any flying around and no change in the aphid population.
With that being said, I found a horn caterpillar on my tomato plants one summer (photo above) that was covered with eggs from a Baraconid wasp. Although I didn’t think to do it when I found this guy, if/when I see another, I plan to put it in a small screened in cage and place in in the greenhouse where the wasps can escape but the caterpillar can not. This way, once the wasps mature and leave the dead worm, they can find a victims in the greenhouse and begin the cycle again by laying their eggs in them.
– Florida UF/IFAS Website
– Galveston County Master Gardeners