By Kathy Feagan
Ensign Wasps (Evania appendigaster:Evaniidae), solitary wasps, also known as nightshade or hatchet wasps, are found worldwide. They are very common in the southern U.S. Originally native to the Orient, they were first discovered in America in 1879. Their petiole attaches at the top of their abdomen, with the compacted abdomen looking like a small flag, thus the name ‘ensign wasp’. These wasps are parasitoids of cockroach eggs. They are very small, less than 1/3”. The female lies on her side, holding the egg sac with her legs. She drums the roach ootheca with her antennae then extends her ovipositor and explores the surface until she finds an appropriate spot for boring. She then begins to repeatedly drill to insert her stinger/ovipositor. She finally breaches the roach ootheca after working for up to 30 minutes, and lays one egg inside the roach ootheca (egg sac). Her egg hatches quickly and eats all of the roach’s eggs. The wasp larvae then go through 5 instars until it reaches maturity. The mature wasp cuts a hole in the roach ootheca and leaves. The newly matured adult wasp then repeats the cycle. Adults live for less than a month. The adults drink nectar from flowers, especially fennel and parsley, and are not known to sting humans. They have been studied for their use as a biological cockroach control.
“Ensign Wasp” by treegrow is licensed under CC BY 2.0 
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Caterpillar Hyposoter Parasitoid (Hyposoter exiguae). These solitary wasps have long antennae, a black head, a very narrow waist and an orange abdomen. They grow from ¼ to ½” long, their length determined by the type of host caterpillar they choose. Inside the host caterpillar, the wasp’s larvae are pale green. This wasp goes through four instars – egg, larvae, pupa, then adult. They mostly prey upon the moth larvae of armyworms, alfalfa caterpillars, tomato fruit worms, cabbage loopers, corn earworms, tussock moths, tobacco hornworm and cutworms (and many more crop pests), laying their eggs in newly birthed caterpillars. Once the wasps’ larvae hatches, it feeds on the caterpillar’s blood as it goes through its first instars then begins to feed on the internal tissues, eating everything except the caterpillar’s skin and head. Once the caterpillar dies, the wasp emerges as pupa and spins a cocoon. Within the cocoon, the wasp will mature to adulthood and exit. Their tiny black and white patched, oblong cocoon is laid on leaves atop the caterpillar carcass. These wasps are considered important biologic controls of caterpillars in alfalfa, crops, fruits, vegetables and nuts.
“2021 08 14 Hyposoter didymator 1c” by Slimguy is licensed under CC BY 4.0 .
Cotesia Wasps (Cotesia congregate) are solitary wasps and parasitoids of hornworm caterpillars and are common in home gardens. Females inject eggs into the caterpillar, the eggs hatch into grub larvae. The grub-like larvae feed for 7 to 14 days inside the hornworm’s caterpillar. The larvae are very tiny, so multiple eggs are laid inside each caterpillar. When the larvae have matured, they chew an exit hole from inside the caterpillar. Then they exit and spin cocoons to live in while they pupate. The cocoons are often mistaken for insect eggs. About 7 days later, usually a day or two after the caterpillar dies, the adult wasps emerge from the cocoon. Adult Cotesia wasps look similar to Ichneumonids (which also attack caterpillars) and have long, thin antennae, four dark wings, long legs and wasp-like bodies. These wasps are considered beneficial, natural control agents of both tomato and tobacco hornworms. Adult wasps feed on nectar from flowers.
“Cotesia adult” by Beatriz Moisset is licensed under CC BY-SA 4.0 
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Rusty Spider Wasps (Tachypompilus ferugineus:Pompilidae) are large (1/2 – 1”), solitary wasps with shiny black to reddish-brown bodies with four narrow bands and iridescent dark purple/blue oily looking wings and long, spiny legs, which usually hang down while they fly. There are many varieties of spider wasps but, in Texas, you will mainly see the rusty spider wasp. Their antennae are curled at the ends. There are over 300 different species of spider wasps in the U.S and over 5,000 species world-wide. They feed on the nectar of flowers, juices from fruits, and aphid’s honeydew. While feeding and hunting, they repeatedly and rapidly flick their wings. Males, who cannot sting, stake a territory, and fight off other males, and wait for females to fly near for mating. Females hunt on the ground and on structures (walls of homes, sheds, etc.) for spiders. When she finds a spider of about the size of herself, she paralyzes it and then drags it (backwards) to the site of her future underground nest. They often prey on wolf, fishing, crab, orb weavers, and jumping spiders. Inside the nest, the wasp lays an egg atop the paralyzed spider’s abdomen. The female’s nests are shallowly dug dens (in soil or wood), prepared after paralyzing their prey. Some species build mud oothecas or use the abandoned mud cells of mud daubers. Others use abandoned holes, cracks in walls and even sometimes the spider’s nest. The spider is then drug into the burrow and the female lays her egg. She then seals off the mouth of the burrow, protecting the prey and egg from predators. Once the egg hatches, the larvae feed on the spider, saving the vital organs for last. Once the larvae matures, it spins itself a cocoon, pupates inside it and later exits as an adult, to reproduce and continue the cycle. Depending on the time of year, the adult can emerge in the same season or overwinters until the next spring. These wasps are not at all aggressive to humans and help provide natural control of spiders and are considered beneficial.
“20220730 Tachypompilus ferrugineus (Rusty Spider Wasp) and Tigrosa sp. prey (3)” by schizoform is licensed under CC BY 2.0 .
Mason Wasps (Pachodynerus erynnis) are small (less than ½”), solitary wasps that are considered valuable insect predators and their populations have been steadily increasing. Males and females have red and black coloring but males have a light, 5-sided spot on their faces. Females have a somewhat similar red coloration atop their heads. All adults feed on flower nectars and help with pollination. After mating, females begin building nests from soil and saliva to make mud. Sometimes they will tunnel through mortar for a nest, or use the crevice of a tree. They also sometimes reuse empty mud dauber nests for their young and in hollow flower stems like from angel’s trumpets. Once the nest is built, females collect and paralyze nearly hairless caterpillar and beetle larvae, then lays an egg on the paralyzed prey. They utilize caterpillars of armyworms, corn earworms, cutworms, cabbage loopers and other garden pests. These wasps do not defend their nests and are only aggressive if threatened. They are considered quite beneficial because they prey on so many caterpillar pests
“Mason Wasp – Euodynerus hidalgo, Meadowood SRMA, Mason Neck, Virginia” by Judy Gallagher is licensed under CC BY 2.0 .
Potter Wasps (Eumenes fraternus) are small (3/8 – ¾”), solitary wasps, and are very similar to the Mason wasp. They are black with yellow marks on the abdomen, black winged and have a very narrow ‘waist’. Females build nests with clay that resemble a vase, usually attached to a twig or leaf. Some build inside hollow twigs, crevices or abandoned mud dauber nests. The female fills the nest with paralyzed caterpillars, moths, spiders and beetle larvae. She then lays a single egg atop the paralyzed prey and seals the top of the ‘vase’. Their nest can hold up to 10 caterpillars. When the egg hatches, the larvae feed on the prey for a few weeks before they pupate. Like a mud dauber nest, if you see an exit hole in the side of the nest, the nest is empty. All adults feed on flower nectar, are pollinators and are not aggressive.
“Potter wasp 20100722” by Bruce Marlin is licensed under CC BY-SA 3.0 .
BCMGA offers several education programs each month. There is a program at 6:00 p.m. on the 1st Tuesday of the month at the South Library Branch in the Mall of Abilene, and the same program is offered again at 10:00 a.m. on the 2nd Friday of the month at the Downtown Library. Watch the BCMGA website and Facebook page for the topics and the dates of these monthly programs.
If you have any questions, call the Taylor County Extension Office at 325-672-6048 or email us at mgardeners@yahoo.com. We hope you visit our website at bcmgtx.org for information on all Big Country Master Gardener events, like us on BCMGA Facebook, and check out training presentations on BCMGA YouTube. We are here to help you.
Until next week, Happy Gardening!