Tips for Reducing Damage from 17-Year Periodical Cicada Swarms

Every 17 years, nature stages one of its most fascinating spectacles: the emergence of periodical cicadas. These unique insects appear in massive swarms, filling the air with their characteristic buzzing and creating a phenomenon that captures the attention of scientists, nature lovers, and homeowners alike. While cicadas are mostly harmless to humans and pets, their sudden abundance and behavior can cause significant damage to young trees, shrubs, and garden plants. If you live in an area expecting a 17-year periodical cicada emergence, it’s important to prepare and protect your property from potential damage.

In this article, we’ll explore practical tips for reducing damage caused by cicada swarms during their cyclical appearance. Understanding cicada behavior and applying preventative strategies can help you safeguard your landscape and minimize the impact of these fascinating but sometimes destructive insects.

Understanding 17-Year Periodical Cicadas

Periodical cicadas (genus Magicicada) are remarkable insects native to North America. Their life cycle includes:

• A lengthy underground nymph stage lasting 13 or 17 years (depending on the brood).
• After this incubation period, millions of adults emerge simultaneously.
• Cicadas spend several weeks above ground mating and laying eggs.
• The females lay eggs by cutting slits into small branches or twigs.
• When eggs hatch, nymphs fall to the ground and burrow underground to feed on root sap, starting the cycle anew.

The synchronized emergence of millions of cicadas creates a natural spectacle but also leads to widespread egg-laying damage on trees. The slits females make in young branches often cause twig dieback, which can stress or kill young or smaller trees if damage is severe.

Why Should You Be Concerned?

Although periodical cicadas do not bite, sting, or spread diseases harmful to humans or pets, they can be problematic for gardeners and tree enthusiasts because:

• Egg-laying damages branches: Female cicadas cut many small slits into the bark of twigs to lay eggs. This process weakens branches.
• Twig dieback: After hatching, many twigs with egg slits dry out and break off.
• Young trees are vulnerable: Small trees (less than 3 inches in diameter) may suffer serious damage from heavy egg-laying.
• Trees under stress are at risk: Trees already weakened by drought, disease, or poor soil conditions suffer more from cicada damage.

The good news is healthy mature trees generally tolerate cicada feeding without permanent harm. The main concern is protecting younger plants, newly planted trees, fruit trees, and ornamental shrubs during cicada outbreaks.

Tips for Reducing Damage from Periodical Cicada Swarms

1. Identify if Your Area Is Affected

Periodical cicadas emerge as broods that appear in localized geographic regions every 17 years. Before taking protective measures:

• Check local extension offices or university entomology departments for maps showing brood emergence areas.
• Look up recent news or government resources mentioning expected emergence dates and locations.

Knowing when and where the emergence will happen enables timely preparation.

2. Protect Young Trees with Netting or Screening

Since female cicadas prefer laying eggs in small branches less than 1/2 inch thick:

• Cover young trees (less than 3 inches trunk diameter) with fine mesh netting or floating row covers before cicada emergence starts.
• Use a mesh size smaller than 1/4 inch to prevent cicadas from reaching twigs.
• Ensure covers stay in place during peak activity (typically 4-6 weeks).

This prevents egg-laying females from accessing branches while allowing sunlight and rain through.

3. Delay Planting New Trees if Possible

If you know a periodical cicada emergence is imminent:

• Avoid planting new trees or shrubs right before expected peak emergence.
• Newly planted young trees are most susceptible to branch damage.

If delay isn’t possible, use protective netting immediately after planting.

4. Prune Damaged Branches Immediately After Emergence

After the adults have died off (usually within a month), inspect your trees:

• Look for twig dieback caused by egg-laying scars, these twigs will appear brown, dry, or brittle.
• Prune away damaged branches back to healthy wood.

Removing dead twigs reduces stress on the tree and prevents secondary infections or infestations.

5. Maintain Tree Health Throughout the Season

Healthy trees are better able to recover from cicada damage:

• Water young trees regularly during dry periods to reduce stress.
• Apply mulch around tree bases to retain soil moisture.
• Avoid excessive fertilization that promotes weak growth prior to emergence but consider balanced feeding afterward.

Strong root systems help sustain growth despite branch loss.

6. Avoid Overuse of Insecticides

Cicadas are not harmful pests that require chemical control because:

• They do not feed on leaves or cause direct defoliation.
• Their life cycle is short above ground , adults die within weeks.

Using insecticides can harm beneficial insects including pollinators without effectively controlling cicadas.

Focus instead on physical barriers like netting rather than pesticides.

7. Protect Fruit Trees Proactively

Fruit tree branches often fall within size preference for egg-laying:

• Use bird netting or fine mesh covers over fruit trees during peak cicada activity.
• Remove any damaged limbs after emergence to avoid fungal infection problems that can affect fruit production.

Taking preventive action helps ensure your fruit harvest isn’t compromised.

8. Educate Yourself About Cicada Behavior

Understanding cicada biology helps ease concerns:

• Adult cicadas live only about 4-6 weeks above ground.
• They do not bite or sting humans or animals.
• The noise they create is loud but harmless , it’s a mating call produced by males vibrating membranes called tymbals.

Knowing this can reduce anxiety about their presence while motivating proactive protection efforts.

9. Consider Temporary Landscape Adjustments

If you have sensitive plants highly vulnerable to branch dieback:

• Temporarily relocate potted plants indoors or into greenhouses during emergence if feasible.
• For delicate shrubs, consider wrapping branches loosely with cloth mesh bags until emergence ends.

Such measures may be labor-intensive but effective for small valuable specimens.

Conclusion

The periodical appearance of 17-year cicada swarms is an awe-inspiring natural event but demands preparation from gardeners and tree owners concerned about plant health. By recognizing potential risks and applying targeted protective strategies such as netting young trees, pruning damaged limbs promptly, maintaining overall plant vigor, and avoiding unnecessary pesticides, you can dramatically reduce damage caused by these emergent insects.

Above all else, remember that mature healthy trees usually withstand cicada swarms quite well with no long-term harm. With proper care and timing awareness, your landscape can survive , and even thrive , despite this spectacular periodic invasion of nature’s noise-makers.

References & Further Reading:

• University Extension Services (e.g., Penn State Extension)
• USDA Forest Service publications on periodical cicadas
• Local cooperative extension entomology bulletins
• Scientific papers on Magicicada ecology and behavior