Parasitic Wasps

Predatory Flies

Predatory Bugs


Predatory Beetles




Parasitic Wasps

Order Hymenoptera

Parasitic wasps:
Importance: Parasitic wasps are one of the most abundant natural enemies available, and probably one of the least understood ecologically by most people. They are also one of the best performers because they are specific to certain hosts and can reach high populations with the right food/overwintering plants. Tricks - have overwintering plants like Queen Anne's lace, yarrow, comfrey, and host plants like cole crops. This improves the overwintering success of wasp populations. It is desirable to have high populations of parasitic wasps early in the season, and they ride herd on the host population. Monitor parasitization rate of desired host(s) through sampling to get percentage parasitization. Can purchase many species - make inundative releases to control outbreaks. Use the spray Bt, Bacillus thuringiensis against caterpillars rather than broad-spectrum insecticides - these kill your beneficials at rates higher than the target hosts. Although Bt will kill most larvae, it doesn't harm wasp pupae or adults.

Identification: Parasitic wasps are generally small (an inch or less long, and most are less than 1/4 inch long) slender, hairless flying insects with 2 pairs of clear to smoky membranous wings and long antennae. Many are black or brown, but some have intricate color patterns. Their size is generally based on the size of their host; e.g. Cicada killer wasps are huge (2 inches or longer), and Trichogramma wasps are the size of the period at the end of this sentence because that is the size of the insect eggs that they attack. Female parasitic wasps usually have a readily visible ovipositor. Most parasitic wasps attack a specific host, such as a caterpillar, or butterfly/moth egg or pupa, beetle egg/larva/pupa, cicada, or other insect eggs, larva or pupa. This specificity of hosts allows you to make sure you have the right wasp present when the hosts (caterpillars, beetles, etc.) show up.

Dispersion by size (and by habits of the host) - small wasps (Aphelinids, Aphiids, Trichogrammatids, Mymarids, Scelionids) stay in field; medium wasps (smaller and medium sized Braconids, Ichneumonids, Eulophids) forage less than 1/4 mile if food/hosts present; larger wasps (Bigger Ichneumonids, Tiphiids, Scoliids, plus predatory wasps like paper wasps and hornets) travel more than 1/4 mile in search of food and hosts.

Cotesia glomerata wasps searches for an imported cabbageworm larva next to feeding damage. A typical pinned Braconid wasp, Cotesia glomerata. Cotesia rubecula stinging ICW larva and placing a single egg inside each host. Cotesia glomerata's yellow cocoons next to the dying host, a 5th instar Imported Cabbageworm caterpillar.


1) Braconids - adult wasps are usually smaller than ichneumonids (less than 1/4 inch) and of more compact build, with long antennae and clear to smoky colored wings. They usually have less than 15 antennal segments. They sting their prey and deposit an egg(s) in the host. Braconids are cocoon makers in the pupal stage, so they can be found on the crop, or nearby plant leaves in fields - cocoons can be single or multiple - yellow or white, usually. If they are fresh, the host cadaver may still be nearby, which can tell you what species of wasp is attacking. These wasps are very important parasites of caterpillars - get them going early to ride herd on pest worms. These wasps like flowers with small, open nectaries, like wild carrot flowers (umbels). Many parasitic wasps will also host-feed - they will drink the hemolymph (blood) of the host as a way of getting protein, too. Overwintering plants are yarrow and comfrey. Leave some crucifers, like broccoli standing or to the side, as many braconids overwinter as cocoons on dead broccoli plants or similar mustards.

Ichneumonids are more slender and enlongated than braconids. Note the long ovipositor on this wasp - it parasitizes wood boring beetle larva. Hyposoter spp. wasps have characteristic black and white spotted cocoons. This woolly worm has been parasitized by a Hyposoter wasp and will not be attending the Woolly Worm Festival.


2) Ichneumonids - Slender, larger (1/4 inch or larger - bigger than braconids) wasps with long legs, long antennae (-more than 15 antennal segments), and long ovipositor. Ichneumonids and braconids are some of the most important parasitic insects. Ichneumonids make cocoons usually inside the host, so you might see a caterpillar skin over an oval black and white striped cocoon (Hyposoter spp.). Or, they use their long ovipositor to bore through plants or wood and sting the larval (like caterpillars or beetle grubs) or pupal hosts inside. Their sting paralyzes their prey temporarily, and allows the female to deposit an egg(s) in or on the host. These wasps are also, like braconids, very important parasites of caterpillars - get them going early and preserve their populations to ride herd on pest worms. They also like umbels and similar flowers that have open nectaries. Same overwintering plants as braconids - yarrow and comfrey, and leave crucifers or similar crop plants as winter harborage.

Chinese Tiphiids on display; China has abundant Tiphia and Scolia resources. Female Tiphia vernalis on choke cherry in spring Tiphia vernalis on Tulip poplar. A female Tiphia vernalis starts hunting for Japanese or Oriental beetle grubs.


3-4) Tiphiids/Scoliids - Identification: Large; look similar to carpenter ants with wings, but quicker and more serpentine. Tiphiids are solid black, and Scoliids have various color patterns - yellow/black, brown with 2 orange spots, etc. If you handle them, the females can give a mild sting. Adult female wasps burrow into the ground to attack grubs - specific wasps for Japanese beetle grub, Oriental beetle grub, Green June beetle grub (Scoliid); etc. They sting the grub, paralyzing it. The wasp then lays an egg on the grub, which hatches and consumes the grub in a week or so. It then spins a brown cocoon in the soil about the size of a small peanut. Wasps overwinter in the cocoon stage below ground. All of these wasps are VERY dependent upon food plants and/or aphid honeydew to realize their high reproductive potential. The spring Tiphia, Tiphia vernalis Rohwer, attacks Japanese/Oriental beetle grubs in April/May. Important food plants for the Spring Tiphia are Tulip poplar, peonies, pyracanthas, forsythia, and plants with aphids for honeydew. Tiphiid/Scoliids also host feed by biting the leg of a grub and drinking the hemolymph that exudes from the wound.The spring Tiphia, Tiphia vernalis Rohwer, attacks Japanese beetle grubs in April/May. Or goto       Click here to see the Tiphia video

5-7)Trichogrammatids/Mymarids/Scelionids - tiny wasps about the size of the period at the end of a sentence. Trichogrammatids and Mymarids (Fairyflies) can be important parasites of the pest eggs of imported cabbageworm, gypsy moth, cabbage looper, cereal leaf beetle, and other pest insect eggs. A somewhat similar family of wasps with similar habits is the Scelionidae - egg parasites of Stinkbugs. Because of their small size, you need a dissecting microscope or a 10X minimum ocular to see them well. They like the small, open nectaries of flowers such as umbellifera, bridal wreath spirea, and yarrow. So you need lots of little clumps of farmscaping plants all over for these guys.

Eulophids are small wasps that are usually metallic green. Eulophid hunts for hosts. Here, a Eulophid attacks Cotesia glomerata larvae inside the host caterpillar. Mexican Bean beetle pupa parasitized by Pediobius.


8)Eulophids - Small to medium sized wasps, usually metallic green or blue. Some are parasitic on pest beetle eggs, like Edovum puttleri against Colorado potato beetle eggs. They have been shown to kill as many eggs through host feeding as they parasitize! They like umbels and similar open flowered plants, like yarrow. Some Eulophids are hyperparasites of the parasitic wasps attacking imported cabbageworm (Tetrastichus galactopus attacking Cotesia glomerata/rubecula/orobeanae).

Pteromalids have a rounded head and red eyes. Pteromalus puparum attacking Imported Cabbageworm pupa. After ovipositing, the female P. puparum host feeds on the puncture wound. Some pteromalids are also hyperparasites, like this one attacking Cotesia glomerata cocoons.


9) Pteromalids - Pupal parasites of caterpillars and beetles, primarily. Identification: Very small (less than 1/8 inch); black with red eyes. Females have the ovipositor attached on the underside at the front end of the abdomen. Ovipositor has saw-like blades to drill into host. Females usually lay around between 10 and 50 eggs or so in a host pupa, depending upon the size of the pupa.

Encarsia inaron adult. Encarsia and whitefly adult. Encarsia parasitizing whitefly nymph. The round exit holes can be used to determine percent parasitization.

10) Encyrtidae - Encarsia spp. and others.

Relative sizes of aphids, flea beetles and parasitic wasps. Green Peach Aphid parasitized by an Aphelinid. Exit hole of wasp in aphid mummy.


11) Aphelinids/Aphiids- I want my mummies! These wasps sting aphids and produce the brown aphid mummies you see in the field. The whitefly parasite Encarsia Formosa is a very important mortality factor against the greenhouse whitefly, and is in commercial production. If you look closely, you may see the exit hole of the wasp, usually at the rear of the aphid or whitefly mummy. Count mummies versus non-mummified aphids to get a handle on percent parasitization. Research has shown that Aphelinid populations generally are isolated in fields, and that nearby populations 1/4 to 1/2 mile away are genetically isolated from one another. So, these don't move much and are dependent upon very localized sources of food for energy and mating sites. Trick: Keep greenhouse temperatures above 76 degrees, and Encarsia can out-reproduce the whitefly by twofold.


European Hornets are about 2 inches long. Paper wasp Polistes spp. on fennel. Yellowjacket foraging on redbud tree leaves. Potter wasp is a predator too.


12) Predatory Wasps - Hornets, Paper Wasps, Yellow jackets, etc. Social insects that are best kept slightly away from your areas of most activity. They like to nest in overhangs or protected areas. They are okay if they are out of the way; otherwise, it is no fun to be chased out of your patch by bald-faced hornets. They forage over a large area, greater than 1/4 mile. Many will feed on caterpillars or similar soft-bodied insects. Predatory wasps will supplement their prey feeding with nectar and pollen from umbellifera, goldenrods, cilantro, sunflowers, and other pollen producing plants. They overwinter as mated queens in your house or outbuildings. Knock down undesirable nests early by blasting them with water or soapy water to kill them.