Tips for Gardeners: Managing Cicada Infestations

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Tips for Gardeners: Managing Cicada Infestations

Protecting Your Garden and Landscape Plants from Cicadas in 2024 (and Planning for 2041)

This summer, the southern regions of the United States experienced a significant surge in cicada populations. These noisy insects, known for their distinctive drone, can have profound effects on local vegetation. Understanding the life cycle of cicadas and their impact on plants is crucial for gardeners and landscapers aiming to protect their gardens from these seasonal visitors.

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The Cicada Life Cycle: A Brief Overview

Cicadas are fascinating insects with a unique life cycle that includes long periods spent underground as nymphs. Most cicada species in the southern U.S. are either annual or periodical. Annual cicadas emerge every year, while periodical cicadas have extended life cycles of 13 or 17 years. In 2024, the region has seen an influx of both types, leading to unprecedented numbers of these insects.

Adults

Adult cicadas emerge from the ground to mate and lay eggs. While they do not feed on vegetation, their sheer numbers can cause damage in several ways. The primary concern is their tendency to congregate in large numbers on trees and shrubs. This can lead to physical damage to branches and twigs, especially when the cicadas engage in egg-laying.


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Eggs

Female cicadas cut slits into tree branches to deposit their eggs. This process, known as oviposition, can severely weaken small branches and twigs. In some cases, branches may die back or even break off, a condition known as "flagging." While mature trees can typically withstand this damage, younger trees and shrubs are more vulnerable and may suffer stunted growth or die if heavily infested.

Nymphs and Larvae

After hatching, cicada nymphs drop to the ground and burrow into the soil, where they feed on plant roots. While the feeding activity of nymphs is not usually fatal to plants, it can stress younger plants and those already weakened by other factors. Over time, extensive root feeding can reduce a plant’s ability to absorb nutrients and water, potentially leading to decline.


Impact of Cicadas on Gardens and Landscapes

The impact of cicadas on gardens and landscape plants can be significant, especially during years of heavy emergence. Here’s how each stage of their life cycle can affect different aspects of your garden:

1. Physical Damage to Plants

The most immediate and visible damage from cicadas comes from their egg-laying activities. The slits they cut into branches can lead to a condition called “cicada flagging,” where parts of the tree die off. This is especially problematic for young trees and shrubs, which are not as resilient as their mature counterparts.

2. Root Stress

As nymphs feed on plant roots underground, they can stress plants by reducing their ability to take up water and nutrients. This is more of a concern for smaller plants, newly planted trees, and vegetables, which may exhibit signs of stress such as wilting or stunted growth during a heavy infestation.

3. Increased Pest Attraction

The presence of cicadas can attract other pests that feed on them, such as birds and rodents. While these predators help keep the cicada population in check, they can also cause additional damage to plants as they forage.

Balancing Ecosystem and Garden Protection

While cicadas are a natural part of the ecosystem and play a role in aerating soil and providing food for wildlife, their presence can be problematic for gardeners. Here are several strategies to balance ecosystem health while minimizing damage to your garden:

1. Protecting Young Trees and Shrubs

To protect young and vulnerable trees from cicada damage, consider using fine netting or mesh to cover them during the peak emergence period. This physical barrier can prevent cicadas from reaching the branches and laying eggs. Be sure to secure the netting tightly around the trunk to prevent cicadas from crawling underneath.

2. Pruning and Maintenance

Pruning infested branches can help manage damage. If you notice flagging or damaged branches, prune them back to a healthy point. This not only removes the damaged sections but also encourages new growth. However, avoid heavy pruning during the peak cicada season, as it can make the plants more susceptible to further damage.

3. Soil Health and Water Management

Maintaining good soil health and proper watering practices can help plants better withstand the stress caused by cicada nymph feeding. Healthy, well-watered plants are more resilient and can recover more quickly from root damage. Consider applying a balanced fertilizer to boost plant health and promote vigorous growth.

4. Integrated Pest Management (IPM)

IPM strategies, including biological controls, can help manage cicada populations. Encouraging natural predators such as birds and parasitic wasps can help keep cicada numbers in check. Additionally, reducing the use of broad-spectrum insecticides can preserve beneficial insects that prey on cicada nymphs and adults.

5. Diversifying Plantings

Diversifying the types of plants in your garden can reduce the overall impact of cicada infestations. By planting a variety of species, you can minimize the risk of widespread damage and ensure that some plants thrive even if others are affected by cicadas.

Since we've experienced the cicada infestation with a combination of 13 and 17 year cicadas, this fall is an ideal time to plant trees and shrubs so they'll be established before the next periodic infestation.

FAQs About Cicadas and Garden Management

1. How long do cicadas stay above ground?

Cicadas typically stay above ground for about four to six weeks, during which they mate, lay eggs, and die. The exact duration can vary depending on the species and environmental conditions.

2. Are cicadas harmful to all plants?

Cicadas primarily affect trees and shrubs, particularly younger and smaller ones, because they burrow underground and eat plant roots. Herbaceous plants and larger, established trees are less likely to suffer significant damage.

3. Can cicada infestations be prevented?

While you cannot completely prevent cicada infestations, using protective netting, maintaining healthy soil, and encouraging natural predators can significantly reduce their impact on your garden.

4. What should I do with cicada-damaged branches?

Prune damaged branches back to a healthy point to encourage new growth. Dispose of the pruned material properly to prevent any remaining eggs from hatching.

5. Will cicadas return every year?

Annual cicadas emerge every year, but periodical cicadas (as we've experienced in 2024) appear in cycles of 13 or 17 years. The severity of their impact varies with each emergence.

Cicadas are a fascinating part of our natural world, but their presence in large numbers can pose challenges for gardeners. Understanding their life cycle and implementing proactive management strategies can help protect your garden and landscape plants from their potentially damaging effects. 

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