What bad impact on the environment does a cicada have?

Cicadas are generally not considered harmful to the environment; in fact, they play a role in nutrient cycling and soil aeration. However, their mass emergence can lead to temporary stress on trees and plants, as they lay eggs by puncturing tree branches. This can result in damage to young trees and may make them more susceptible to diseases. Additionally, their sheer numbers during periodic emergences can lead to localized disturbances in the ecosystem, although these effects are typically short-lived.