Updated: July 8, 2025

The red-shanked grasshopper (Melanoplus femurrubrum) is a common pest affecting agricultural fields, rangelands, and gardens across North America. Known for their distinctive red-colored hind legs, these grasshoppers can cause significant damage by feeding on a variety of crops and plants. Effective management of red-shanked grasshopper populations is crucial to minimize crop loss and maintain healthy ecosystems.

Insecticides play a vital role in controlling these pests when populations reach damaging levels. This article explores the best insecticides for managing red-shanked grasshopper populations, including their modes of action, application methods, environmental impact considerations, and integrated pest management strategies.

Understanding the Red-Shanked Grasshopper

Before diving into insecticide options, it’s important to understand the biology and behavior of the red-shanked grasshopper:

  • Identification: Adults have distinctive red hind legs with black markings; they are medium-sized grasshoppers.
  • Habitat: Prefer grassy fields, prairies, rangelands, and agricultural areas.
  • Diet: Feed on leaves, stems, and sometimes flowers of grasses and broadleaf plants.
  • Life cycle: Eggs are laid in soil during late summer; nymphs hatch in spring and mature through several instars.
  • Population outbreaks: Can fluctuate due to weather conditions, predation, and food availability.

Control decisions often depend on population density assessments conducted early in the growing season.

When to Use Insecticides

Insecticides are generally recommended when grasshopper density exceeds economic thresholds that indicate potential for significant crop damage. These thresholds can vary by crop type but commonly range from 8-15 grasshoppers per square meter for many crops.

Early-season applications targeting nymphs are usually more effective than late-season treatments on adults since younger stages are less mobile and more susceptible.

Categories of Insecticides Effective Against Red-Shanked Grasshoppers

Several classes of insecticides have proven efficacy against red-shanked grasshoppers. These include:

1. Pyrethroids

Pyrethroids are synthetic derivatives of natural pyrethrins extracted from chrysanthemum flowers. They disrupt insect nervous systems causing paralysis and death.

  • Common active ingredients: Lambda-cyhalothrin, bifenthrin, permethrin.
  • Advantages:
  • Fast knockdown effect.
  • Broad-spectrum activity.
  • Relatively low mammalian toxicity.
  • Application tips:
  • Use at recommended label rates.
  • Apply during calm weather to reduce drift.
  • Effective for foliar spray targeting nymphs and adults.
  • Limitations:
  • Pyrethroid resistance can develop in some insect populations.
  • Toxic to beneficial insects like pollinators—avoid spraying during bloom periods.

2. Organophosphates

Organophosphates inhibit acetylcholinesterase enzyme function in insects’ nervous systems leading to accumulation of neurotransmitters and eventual death.

  • Common active ingredients: Malathion, chlorpyrifos (restricted use), acephate.
  • Advantages:
  • Effective against a wide range of insects including grasshoppers.
  • Can be used in various formulations including sprays and baits.
  • Application tips:
  • Follow label restrictions carefully due to higher mammalian toxicity.
  • Apply in early morning or late evening to minimize non-target impacts.
  • Limitations:
  • Environmental persistence concerns.
  • High toxicity to aquatic organisms.
  • Growing regulatory restrictions limiting use.

3. Neonicotinoids

Neonicotinoids act on nicotinic acetylcholine receptors causing paralysis.

  • Common active ingredients: Imidacloprid, thiamethoxam.
  • Advantages:
  • Systemic action allows uptake by plants providing residual control.
  • Useful as seed treatments or soil drenches in some crops.
  • Application tips:
  • Use according to integrated pest management guidelines to avoid resistance buildup.
  • Avoid use during flowering stages to protect pollinators.
  • Limitations:
  • Concerns about sub-lethal effects on beneficial insects and pollinators.
  • Resistance potential with repeated use.

4. Carbamates

These interfere with nerve transmission similarly to organophosphates but generally have shorter residual activity.

  • Common active ingredients: Carbaryl (Sevin).
  • Advantages:
  • Broad-spectrum insecticide effective against many chewing insects including grasshoppers.
  • Often available in liquid and dust formulations for flexible application options.
  • Application tips:
  • Apply at recommended rates for target pests.
  • Avoid drift onto sensitive crops or water bodies.
  • Limitations:
  • Toxicity to some beneficial insect species.

5. Biological Insecticides

Biological insecticides offer environmentally friendly alternatives.

  • Example products: Products containing Beauveria bassiana (a fungal pathogen), Nosema locustae (a microsporidian pathogen).
  • Advantages:
  • Specificity to grasshoppers reducing non-target effects.
  • Can be integrated into pest management programs as a preventative measure rather than curative treatment alone.
  • Application tips:
  • Best used when populations are low and environmental conditions favor pathogen activity (warmth, humidity).
  • Limitations:
  • Slower acting than chemical insecticides.
  • Effectiveness varies with environmental conditions.

Application Considerations

Choosing the right insecticide is only part of effective grasshopper management. Proper application techniques maximize efficacy:

Timing

Target nymphal stages soon after hatching in spring or early summer when they are concentrated near egg-laying sites and less mobile.

Coverage

Achieve thorough spray coverage on foliage where grasshoppers feed. Avoid missed areas that could serve as refuges for surviving insects.

Weather Conditions

Apply on calm days with low wind speeds to prevent drift and maximize deposition. Avoid rainy days that may wash off insecticides before absorption. Early morning or late afternoon applications reduce exposure risks to pollinators.

Safety Precautions

Follow all label instructions related to personal protective equipment (PPE), application rates, buffer zones near water bodies, and re-entry intervals.

Integrated Pest Management (IPM) Strategies

While insecticides are valuable tools against red-shanked grasshoppers, relying solely on chemical control can lead to resistance development and negative environmental impacts. Incorporating IPM principles enhances long-term control success:

Monitoring and Thresholds

Regularly scout fields for presence and density of grasshopper nymphs and adults. Utilize economic thresholds to guide treatment decisions rather than applying prophylactically.

Cultural Controls

Implement practices such as altering planting dates, maintaining healthy crop stands, removing weeds that serve as alternate hosts, and managing field margins where grasshoppers may overwinter.

Biological Controls

Encourage natural enemies like birds, spiders, predatory beetles, and parasitic wasps that naturally suppress grasshopper populations.

Habitat Management

Maintaining diverse landscapes with non-crop vegetation supports natural predator populations helping reduce pest outbreaks over time.

Environmental Impact and Resistance Management

Repeated use of a single class of insecticide increases the risk of resistance development among red-shanked grasshoppers. To mitigate this:

  • Rotate insecticides with different modes of action using Insecticide Resistance Action Committee (IRAC) guidelines.
  • Use lower-risk options such as biological controls where feasible.
  • Minimize broad-spectrum applications that harm beneficial organisms integral to ecosystem balance.

Careful selection based on local regulations and environmental sensitivity is essential to prevent contamination of soil and water resources.

Conclusion

Managing red-shanked grasshopper populations effectively requires a combination of accurate monitoring, timely intervention, appropriate insecticide selection, and integration with cultural and biological controls. Pyrethroids remain widely used due to their rapid knockdown ability while organophosphates and carbamates provide additional chemical control options albeit with greater environmental considerations. Biological insecticides offer promising alternatives within IPM frameworks emphasizing sustainability.

Farmers and land managers should prioritize early-season treatments targeting nymph stages along with prudent insecticide rotation strategies to preserve control efficacy over time. By combining chemical tools with ecological approaches, it is possible to reduce damage caused by red-shanked grasshoppers while safeguarding beneficial species vital for agroecosystem health.

Related Posts:

Red-Shanked Grasshopper