The surge in grasshoppers this season is a common natural phenomenon. Grasshoppers are generalist herbivores, feeding on a wide variety of plants, and their populations naturally rise and fall in cyclical patterns. While many species exist, only a small number are considered agricultural pests. These pests are distinct from swarming locusts, which are a specific type of grasshopper that changes its behavior and appearance to form large swarms. The current high numbers result from specific environmental conditions aligning perfectly with the insects’ life cycle.
Environmental Factors Driving the Increase
High grasshopper populations are driven by favorable weather events spanning two years. A mild winter, especially one with insulating snow cover, significantly increases the survival rate of eggs laid in the soil during the previous fall. Without this insulation, prolonged sub-zero temperatures cause high mortality, but a mild winter allows a larger initial population to survive until spring.
The next major factor is drought or hot, dry conditions during the previous summer and fall. Dry weather reduces the presence of natural fungal pathogens, which thrive in warm, humid conditions and can decimate grasshopper populations. Drought also increases the amount of bare ground, which females favor for laying their egg pods.
The ideal scenario is followed by a warm, relatively dry spring and early summer. While heavy rain in June can drown young nymphs, the eggs are resilient and can survive being underwater. Warm temperatures accelerate the development of the nymphs, pushing them quickly through their vulnerable stages. Dry conditions continue to suppress the growth of disease-causing fungi.
Grasshopper Life Cycle and Reproduction Rates
Most pest species undergo a simple metamorphosis, progressing through three stages: egg, nymph, and adult. Females lay their eggs in clusters called egg pods, burying them underground. One female can produce 100 to 300 eggs during her adult lifespan.
Favorable weather translates directly into a high number of surviving eggs hatching into nymphs in the spring. The nymphs go through five or six molts before reaching adulthood. Warm temperatures speed up this development, allowing the insects to mature in as little as 30 to 50 days.
A rapid development cycle means new adults emerge earlier in the summer, giving them a longer period to feed and reproduce. If conditions remain warm and dry, the newly matured females begin laying eggs sooner, leading to a larger total number of egg pods deposited for the next generation. This high reproductive capacity, combined with increased survival, drives population growth.
Impacts on Local Ecosystems and Agriculture
A surge in grasshopper numbers affects both natural ecosystems and cultivated land. A high density, such as 10 grasshoppers per square yard, can consume available vegetation rapidly. In agricultural settings, this results in direct crop loss as the insects chew on and consume plant tissues.
The damage extends to grazing lands, where the insects compete directly with livestock and native herbivores for forage. When natural vegetation dries out, grasshoppers move into remaining green areas, including urban lawns and gardens, destroying vegetation in their path. This influx provides a temporary boost for natural enemies, such as birds, spiders, and certain flies. Sustained feeding pressure can also lead to changes in plant composition, as grasshoppers consume the most palatable plants, leaving behind less-preferred species.
Managing Large Grasshopper Populations
Controlling a large grasshopper population requires proactive measures before the population peaks. On a small scale, physical barriers or early morning removal can reduce damage in gardens. For larger areas, cultural controls are effective, such as tilling field margins in the fall to expose and destroy the egg pods.
Chemical control is often necessary for severe outbreaks. It is most effective when applied early in the season when the grasshoppers are still young nymphs. Smaller nymphs are more susceptible to insecticides, and treating them before they can fly prevents migration and egg laying. Biological control options involve using natural enemies, which can be applied with bait to infect the young insects. Timing is important, as these agents must be applied before the grasshoppers reach the mobile adult stage to be effective.