Tips to Minimize Plant Damage from 17-Year Periodical Cicada Swarms

Every 17 years, certain regions in the United States experience a remarkable natural event: the emergence of periodical cicadas. These insects, known for their loud choruses and synchronized life cycles, appear in vast swarms that can number in the millions per acre. While fascinating from an ecological and scientific standpoint, periodical cicadas pose a significant threat to gardens, orchards, and young trees. Their feeding and egg-laying habits can cause extensive damage to plants if precautions are not taken.

In this article, we will explore practical strategies to minimize plant damage caused by 17-year periodical cicada swarms, helping gardeners and farmers protect their valuable greenery during these extraordinary years.

Understanding 17-Year Periodical Cicadas

Before diving into prevention tips, it’s important to understand the behavior of these cicadas:

• Life Cycle: Periodical cicadas spend most of their lives underground as nymphs, feeding on root sap for 17 years.
• Emergence: After 17 years, they emerge simultaneously in the spring or early summer as adults.
• Adult Activity: Adult males sing loudly to attract females. After mating, females use their ovipositors (egg-laying organs) to cut slits into small tree branches or twigs and deposit eggs.
• Damage Mechanism: The egg-laying process can cause branch dieback or “flagging,” where affected twigs wither and break off. In large numbers, this can stress or even kill young trees and shrubs.

Why Protecting Plants Matters

While mature trees often withstand cicada damage without lasting harm, young trees (up to 3-4 years old), fruit trees, and ornamental shrubs are vulnerable. Severe cicada infestation can stunt growth, reduce crop yields, lower aesthetic value, and sometimes kill plants outright.

Taking proactive steps before and during cicada emergence helps safeguard your garden’s health and productivity.

Tips to Minimize Plant Damage from Cicada Swarms

1. Identify Vulnerable Plants Early

Periodical cicadas prefer laying eggs in small branches roughly the diameter of a pencil or less. Young saplings, small fruit trees (apples, cherries, peaches), roses, blueberries, and ornamental shrubs are most at risk.

Action: Make a list of all susceptible plants in your yard or orchard. Focus protection efforts on those less than four years old or with thin branches.

2. Use Physical Barriers

One of the most effective ways to prevent cicada egg-laying is by physically excluding them from your plants.

• Netting or Mesh Covers: Cover vulnerable plants with fine-mesh netting (with holes smaller than about 1/4 inch) starting before cicadas emerge until after they have left (usually around 4-6 weeks).
• Floating Row Covers: Lightweight fabric covers allow air and light through but block insects.

Secure edges tightly to prevent cicadas from entering underneath and ensure coverage extends over all branches.

Important: Remove covers promptly after the emergence period to avoid overheating or stressing plants.

3. Delay Planting Young Trees

If possible, avoid planting new saplings right before a predicted periodical cicada emergence year. Newly planted trees with tender branches are more susceptible to damage.

Alternative: Plan your tree planting schedule around cicada cycles , either well before or several years after emergence events , to reduce the risk window.

4. Prune Damaged Branches Properly

If you notice twig dieback or flagging caused by egg-laying slits:

• Use clean pruning shears to remove damaged branches well below the affected area.
• Discard pruned material away from healthy plants since egg masses may still be present.
• Pruning encourages healthy new growth and reduces stress on the plant.

Pruning should ideally be done soon after cicada activity subsides but before bud break if possible.

5. Maintain Tree Health with Proper Care

Strong, healthy plants are better equipped to withstand stress induced by cicada feeding and egg-laying.

• Water Regularly: Especially during dry spells; well-hydrated trees recover faster.
• Fertilize Appropriately: Use balanced fertilizers to support growth but avoid excessive nitrogen that may encourage overly tender shoots attractive to cicadas.
• Mulch Around Trees: Helps retain moisture and improves soil conditions.

Healthy root systems and robust growth patterns help trees compensate for cicada damage over time.

6. Avoid Chemical Pesticides Unless Absolutely Necessary

Most insecticides are ineffective against adult periodical cicadas due to their short above-ground adult phase and large numbers. Moreover, chemical treatments can harm beneficial insects like pollinators or natural predators of other pests.

If chemical control is considered:

• Use only pesticides labeled safe for use on fruit trees.
• Apply carefully following all instructions.
• Target specific areas rather than blanket spraying.

Non-chemical management is recommended whenever possible for environmental safety.

7. Monitor Cicada Emergence Timing

Periodical cicadas emerge within certain windows usually between late April through June depending on region and weather conditions.

Monitoring helps:

• Plan installation of protective netting before adults surface.
• Time pruning of damaged branches promptly after swarming ends.

Many universities and extension services provide emergence maps and updates , stay informed via local resources.

8. Encourage Natural Predators

Several bird species feed on adult cicadas during emergence , blue jays, crows, grackles , while spiders and predatory insects target nymphs when they emerge from soil.

Promoting biodiversity in your garden via native plantings, bird houses, water sources, and pesticide avoidance supports these natural controls which may reduce cicada population pressure locally over time.

9. Protect Fruit Trees Specifically with Cage Structures

For orchards or high-value fruit trees:

• Construct temporary frames around trees using PVC pipes or wood.
• Wrap with fine mesh netting secured tightly around frames.

This method allows air circulation while fully protecting delicate branches from female oviposition scars minimizing crop loss potential dramatically during active periods.

10. Educate Neighbors About Cicada Impact

Since periodical cicadas affect entire neighborhoods or regions simultaneously:

• Share information about protective measures with neighbors.
• Coordinate protection efforts such as community netting projects.

Widespread cooperation reduces overall damage levels improving outcomes for everyone’s plantings.

Conclusion

The spectacular emergence of 17-year periodical cicadas is a unique natural phenomenon that reminds us of nature’s rhythms but also challenges gardeners and growers due to potential plant damage. By understanding their behavior and applying preventative strategies like physical barriers, timely pruning, maintaining plant health, and monitoring emergence timing, you can significantly reduce harm to young trees and valuable crops during these events.

Adopting sustainable practices that encourage natural predators while minimizing chemical use ensures healthy gardens ready to thrive long after the fleeting swarm has passed. With careful planning and community awareness, your plants can survive, and even flourish, despite one of nature’s loudest celebrations every seventeen years.