Beneficial Parasitic Braconid Wasps
Braconidae (Cotesia congregatus) The Braconidae are a family of parasitoid wasps. After the Ichneumonidae, braconids make up the second largest family in the order Hymenoptera, with approximately 17,000 recognized species and many thousands more undescribed. Wikipedia Scientific name: Braconidae Higher classification: Ichneumonoidea Order: Hymenopterans Rank: Family Class: Insecta These wasps are parasitic insects that prey on horn worms and other garden pests; they hunt them down and inject 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 of parasitoid wasps, in fact there are over 2,000 species in North American alone. Bracon, Chelonus, Cotesia, Leiophron, Macrocentrus and Opius are common genera. Most species are tiny, less than half-inch long.
The female wasps lays her eggs just under the skin of the hot. After they have matured they bore through the worm’s skin and spin a cocoon and attach themselves to the worm. The larvae feed inside the caterpillar and when they are fully grown, chewing their way out of the host’s body. The cocoons emerge as adult Braconid Wasps that will start hunting for pests to continue the cycle. Braconid wasps won’t sting humans unless they are abused. They are found throughout North America. The ichneumon wasp parasitizes garden pests such as cutworms, corn ear-worm, white grubs and various caterpillars.Parasitic wasps get most of their protein from the host insect or spider they eat as larvae. Adult parasitic wasps mostly just drink nectar. Most non-parasitic wasps are predators and scavengers. They feed on dead animals, or hunt insects and spiders, and use their sting to paralyze their prey.Some braconids are solitary, with just one wasp developing in a host, others are gregarious, with dozens or sometimes hundreds of wasps emerging from a single host. Gardeners who raise tomatoes are grateful for braconids that attack hornworm caterpillars.
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.