It can feel like something straight out of a science fiction movie this time of year. Giant wasps seem to be flying around the yard, and armies of creepy crawlers are marching into homes. While these insects may look intimidating, the good news is they are usually more nuisance than danger.
One insect that often gets people's attention is the cicada killer wasp. Its name sounds frightening, and its size can be alarming. Cicada killers are the largest wasps found in Nebraska, growing up to two inches long. With their black bodies and bright yellow markings, they are hard to miss.
Despite their impressive appearance, cicada killers are surprisingly gentle.
As their name suggests, these wasps hunt cicadas. Female cicada killers listen for the loud songs of cicadas, sting them to paralyze them, and carry them back to underground burrows. There, they lay an egg on the paralyzed cicada. When the egg hatches, the developing wasp larva feeds on the cicada before emerging the following year.
Their nesting sites are often what concern homeowners the most. Cicada killers prefer bare, well-drained soil and frequently build burrows along sidewalks, driveways, retaining walls, or landscape beds. The entrance to the nest is about one-half inch wide and is usually surrounded by a small mound of freshly excavated soil.
If you walk near a nest, you may notice a wasp flying toward you or circling around your head. While this behavior can be unsettling, it is usually harmless. Male cicada killers often patrol nesting areas but cannot sting. Females can sting, but they are very docile and rarely do so unless they are handled or severely threatened.
Because these wasps are beneficial predators of cicadas, control is rarely necessary. If they become a nuisance, reducing areas of bare soil by maintaining a dense lawn or applying mulch in landscape beds can discourage nesting. If treatment is needed, use an insecticide labeled for wasps and always follow the directions on the label. Applications are most effective during the cooler parts of the day when the wasps are inside their burrows.
While cicada killers stay outdoors, other pests are beginning to make themselves at home indoors.
Millipedes are one of the most common home invaders during late summer. Although many people think they are insects, millipedes are actually more closely related to centipedes. They have two pairs of legs on most body segments, giving them their familiar "many-legged" appearance.
Millipedes are harmless. They do not bite, sting, or damage furniture or buildings. When disturbed, they typically curl into a tight spiral for protection.
Millipedes feed on decaying leaves and other organic matter outdoors. During periods of hot, dry weather or after heavy rains, they sometimes wander into homes while searching for cooler, more humid conditions. Once indoors, they usually survive only a short time and become little more than a nuisance. Sweeping or vacuuming them up is usually all that is needed.
Another insect that commonly appears inside homes this time of year is the strawberry root weevil. These small, dark brown to black beetles are about one-quarter inch long and are often mistaken for ticks. Unlike ticks, however, they have six legs instead of eight.
The larvae feed on the roots of strawberries, evergreens, brambles, and grapes. Adults emerge during the summer and feed on the edges of leaves, leaving small notches along the margins. Beginning in late July and continuing into August, they often migrate into homes.
Fortunately, strawberry root weevils do not reproduce indoors or damage household items. They are attracted to moisture and are commonly found in sinks, bathtubs, or basement floors. Their migration usually lasts only a few weeks before ending on its own. Vacuuming or sweeping them up is typically the easiest solution.
If strawberry root weevils or millipedes have been a recurring problem, a perimeter insecticide treatment around the outside foundation of the home before they begin migrating may help reduce the number that find their way indoors. Products containing bifenthrin, cyfluthrin, or cypermethrin are commonly labeled for this purpose. As always, carefully read and follow all label directions.
Whether it is a giant-looking wasp in the yard or a parade of tiny visitors inside the house, most of these seasonal pests are more startling than harmful. Learning a little about their habits can make them much less intimidating and help you decide when action is needed and when nature is simply doing its job.
Elizabeth Exstrom is a Horticulture Extension Educator with Nebraska Extension in Hall County. For research-based gardening information, contact Elizabeth at elizabeth.exstrom@unl.edu, visit huskerhort.com, or follow HuskerHort on Facebook and Twitter.