Gardening: Huge cicada killers are beneficial

As I was sitting in the garden the other day, I noticed a huge insect flying just above the ground.

When it got closer, I recognized it as the greatly beneficial cicada killer, which is always welcome in my garden.

Have you noticed these huge wasp-like creatures beginning to appear in your landscape the past couple of weeks? These are cicada killers, which feed on cicadas and katydids in our area, and they are just now beginning to emerge from their winter burrows.

Although they are large and look dangerous, cicada killers are actually beneficial insects that are good for our environment because they help to keep the cicada population in control.

Cicada killers reach up to 1-1 ½ inches in length and they are black or rust red in color, except for a rusty red head and thorax, and yellow band markings on the abdomen. Their wings are russet yellow.

As with all wasps, only the females have stingers; although they seem aggressive, they actually just use their impressive size to scare off predators, including people. As one of the largest wasps encountered, females are capable of stinging, but they are rarely aggressive toward humans or animals unless they are threatened. Males are incapable of stinging, but can be more aggressive.

Cicada killers become active in July and August, which coincides with the annual appearance of our cicada populations here in Oklahoma. After emerging from their underground nests, these wasps mate and then nest in soft soil or sandy areas, digging burrows about 6 inches deep, turning and extending them another 6 or more inches. Females are solitary and each one takes care of its own nest, even though they appear to be nesting in a common area.

They attack, sting and paralyze cicadas, and then fly, glide or drag the cicadas back to their nests. The female then deposits an egg on the cicada and seals the burrow. The egg hatches and feeds on the cicada through the winter, then the adult emerges in the summer.

The cicada killer wasp produces one generation a year, and the adults die after building nests and providing nutritious cicadas for their eggs. The larvae feed only on cicadas, but the adults will feed on flower nectar.

As tempting as it is to use insecticides to kill these huge wasps, please don’t — they play a vital role in reducing the populations of annual cicadas.

Although the annual cicadas arrive in much smaller numbers compared to 17-year periodical cicadas, they damage deciduous trees by laying eggs under the soft bark of the new growth on the trees’ terminal branches. Since they emerge each year in mid-July, cicada killers are not significant predators of periodical (13 and 17-year) cicadas, which emerge in May and June and die off by mid-July.

Some dogs and cats may catch cicada killers, but usually only once. Those that pick females probably will be stung, remember it and associate the experience with the buzzing sound.

Some may have a severe reaction to the venom, especially if stung in the mouth; if that happens, take your pet to a veterinarian immediately.

Wasp flight begins in early morning and can continue until dusk, but these wasps remain in their burrows at night.

Cicada killers may dig in the loose soil in vegetable gardens or flower beds, which may disrupt plant root systems. If only a few plants are affected, drench the area around the plant base, since wasps do not like wet soil and may abandon the site.

However, do not drench soil around plants with an insecticide, because it may damage the roots and/or result in a residue in the plant.

Remember, cicada killers are beneficial insects, and we need them to control the cicada population.