Number 15 - September 12, 2018 Getting to Know Common Wasps available, yellowjackets may become persistent in their search for food and Throughout the summer you may en- sting more easily. Their stings are pain- counter many different types of ful and can be life-threatening for people wasps. These wasps can look similar at with wasp or bee allergies. These and first glance but they often have very dif- other yellowjacket species may need to ferent natural histories and behav- be controlled if they nest in a high traffic iors. While one wasp species might be area, a location where work needs to be aggressive and sting, another may be done, or a location where children more interested in the food you’re serv- play. Wasps and bees are active during ing at your family picnic or the juicy spi- the day, so if nest control is needed, an ders in your garden. The following de- insecticide labeled for wasps should be scriptions are intended to help applied at night. landscape professionals and gardeners identify a few common wasps and de- Northern paper wasps (Polistes fusca- termine whether they require control or tus) are a species you might recognize as may be neutral or beneficial in your the wasps that build a nest under over- shared space. hangs or near outdoor lights on homes. Their nests are sometimes called Yellow Jackets, Hornets, Paper Wasps and “umbrella nests” because they often have Potter Wasps (Vespidae) a curved top with open comb-like cells on the underside. The nests are built in the While adult eastern yellowjackets spring by a few females but after a queen (Vespula maculifrons) feed on nectar and is established, the nest may grow to other sweet foods, they seek out protein house as many as 200 individuals. rich foods to feed their grub-like young. They may carry insects or bits of Northern paper wasps forage for protein meat from a picnic or trashcan back to rich food like insects and bits of carrion, their nests to feed their young. The nests as well as sweet foods like nectar and are constructed underground and may fruit. Northern paper wasps are usually house as many as 2000 individuals. Like docile but may become aggressive if honey bees, yellowjackets are social and their nest is disturbed. Like eastern yel- their nests house queens, workers and lowjackets, they can be controlled if they drones (males). become a risk to people in the area and should be controlled at night. Early in the season these insects may not be aggressive, but as the season pro- Potter wasps (Eumenes fraternus) are gresses and food sources become less solitary in nature. Each female builds a marble sized mud urn to house one or large size, but they are a native species multiple offspring. The nests may be built that rarely sting humans. Asian hornets on plants or on the sides of homes. The are not established in North Ameri- adult collects insect larvae or spiders and ca. For more information about cicada puts them inside the mud nest before lay- killers, please refer to Issue 11 of the ing one or more eggs and sealing the Home, Yard & Garden Pest Newsletter. chamber. The young will hatch and feed on the stored food items until they Spider Wasps (Pompilidae) emerge from the nest as adults. The adults feed on nectar from flowers. These Spider wasps vary in size but most are wasps rarely sting people and may help about ½ inch long. They are usually remove caterpillars in the area. black, but may have a bluish shine, with transparent wings. Wasps in this group Thread-waisted Wasps (Sphecidae) stun spiders with a venomous sting and are protected from the spider’s bite by Black and yellow mud daubers their hard exoskeleton. After stunning (Sceliphron caementarium) are solitary the spider, the wasp will carry it back to wasps about 1 inch long. These wasps her burrow or mud cell to feed her sin- usually have an elongated and very gle offspring. Adult wasps feed on the slender attachment point between their nectar of flowers or honeydew produced abdomen and thorax. Nests are con- by aphids. Spider wasps are not aggres- structed using small amounts of mud sive but may sting if they are threatened carried from puddles or other bodies of or handled. Spider wasp species in Illi- water and situated in sheltered loca- nois can have a mildly painful sting, tions, including porches and building though some species native to the overhangs. These wasps are behavior- Southwest (tarantula hawks) can pro- ally similar to potter wasps, preying up- duce a very painful sting. Give these in- on insects and spiders, then storing and sects a respectful distance if you are va- sealing them in their nests for their de- cationing in the Southwest. veloping young. The adult wasps feed on the nectar of flowers like Queen Anne’s Parasitoid Wasps (multiple families) lace and rarely sting people. Parasitoid wasps feed and develop on Cicada killers (Sphecius speciosus) are other insects, making them beneficial to large wasps, about 2 inches long, with landscapers and gardeners. The images red-brown heads, black bodies and yel- above show a tomato hornworm (left) low banding on their abdomens. Females that has been parasitized by braconid sting and paralyze cicadas, which they wasps (similar species shown carry back to their subterranean burrow right). These wasps lay their eggs in the to feed their young. Females may sting caterpillars. As the young develop inside people but this typically only occurs if the caterpillars, the caterpillars will someone attempts to handle them or if slow or stop feeding on the plants. When they are stepped on. the young larvae mature, they will pu- pate in tiny cocoons on the surface of These animals are sometimes confused the parasitized caterpillars (pictured with Asian hornets because of their left). These tiny cocoons are a good indi- cation that these beneficial insects are up the good fight. Do NOT let these making your garden their home. When weeds remain onsite. They have likely they emerge as adult wasps, they will flowered or produced seed. Take the feed on the pollen, nectar of flowers or time to remove them carefully to pre- honeydew from aphids, then seek out a vent further seed dissemination. You new caterpillar host for their own may recall the old saying, “One year’s young. Parasitoid wasps do not sting seeding makes seven years’ weeding.” I people the way a hornet or bee might. If don’t know who the poor misguided you find a parasitized caterpillar, the soul was who penned this, but I can tell best thing to do is leave it undisturbed you that it is a lot longer than seven. so the wasps can reproduce and con- sume more pest caterpillars. (Sarah According to Michigan State University Hughson) Extension Bulletin E-2931, ‘Integrated Weed Management “One Year’s Seed- ing…”’, seeds of various weed species Do Not Let Weeds Go to Seed persist in the soil for different lengths of time. Once weed seeds are produced and It is late in the growing season. Many dispersed, they can either germinate and plants (and gardeners including myself) emerge, germinate and die, lie dormant, are running out of speed and ambition. I become non-viable, decay, be eaten, or be have heard a few say that they are tired removed by wind and water. of what has been blooming all summer and they are ready for a change or ready The problem of course for us is the seeds for the cold weather to hit. This growing that lie dormant. For those, germination season may be coming to a close, but I could occur the following year or many can assure you that many weeds are still years from now. Research has been done happily growing. on many common weed species to de- termine their persistence in the soil Remain diligent in your weed control seedbank. The years required for a 99% efforts. With the cooler temperatures reduction in seed number is fairly small we had recently, came a new flush of for giant ragweed and common sunflow- cool-season weeds. I am seeing a fair er at only two years. However, velvetleaf amount of common chickweed and hen- and common lambsquarters seeds take bit seedlings. Additionally, I am seeing much longer to see this same reduction quite a bit of dandelion growth, with at 56 and 78 years, respectively. Even a much of it being seedlings. 50% reduction for common lambsquar- ters would still take 12 years. And we This time of year is also when the sum- aren’t talking about a few seeds either. mer annuals such as prostrate spurge, These species are abundant producers of common purslane, and prostate knot- seed. One common lambsquarters plant weed reach maturity and become quite can produce 72,500, while one velvetleaf noticeable in the landscape. The days can produce 7,800. are getting shorter which affects the amount of time we are able to spend So, if we let down our guard in the gar- gardening. You may be weary of bat- den to head inside for pumpkin spice tling weeds, but I encourage you to keep anything, and a single velvetleaf plant goes to seed, we can be left with a ries the spores to nearby developing whopping 3,900 seeds in the soil 12 leaves of susceptible hosts where the years down the road, and we can still be infection occurs. battling the offspring of that plant 50 years later.