How To Get Rid Of May Beetles: Complete Elimination And Prevention Guide

May beetles, commonly known as June bugs, can severely damage turfgrass roots during their larval grub stage and defoliate ornamental trees as adults. Achieving lasting control requires a dual-pronged approach targeting both the subterranean grubs in soil and the foliage-feeding adults above ground using targeted biological, mechanical, and chemical strategies.

Pre-Operation & Equipment Checklist

Successful pest management requires understanding the distinct life cycle of Phyllophaga species. Adult beetles emerge in late spring to mate and lay eggs in soil, hatching into C-shaped white grubs that feed on organic matter and grass roots for one to three years depending on the species.

• Essential Gear and Materials: Heavy-duty garden rake, soil sampling trowel, broadcast fertilizer spreader, liquid hose-end sprayer, high-intensity outdoor bucket light, and collection bucket filled with soapy water.
• Treatment Products: Entomopathogenic nematodes (Heterorhabditis bacteriophora), Bacillus thuringiensis galleriae (Bt), imidacloprid- or chlorantraniliprole-based systemic insecticides, and neem oil for adult foliage defense.
• Prerequisite Standards: Conduct a turf soil core sample (4-inch by 4-inch square) in late summer to calculate grub density. Threshold treatment is warranted if populations exceed 8 to 10 grubs per square foot.
• Estimated Budget and Duration: $30 to $100 depending on yard square footage; execution spans seasonal intervals (spring adult emergence and late summer grub activity), requiring 2 to 4 hours of active labor per phase.

Step-by-Step Eradication and Control Workflow

Step 1: Conduct Soil Audits and Map Infestation Zones

Perform systematic core sampling across your lawn in August or September when grubs are actively feeding near the surface. Cut three sides of a 1-foot square patch of turf, peel back the sod, and count the white, C-shaped larvae in the top two inches of soil.

1. Map areas where the turf feels spongy or pulls up easily like a loose carpet.
2. Record the exact number of grubs per square foot across sunny and shady zones.
3. If counts remain below 5 per square foot, natural aeration and fertilization usually suffice; higher numbers require immediate intervention.

Pro-Tip: Focus your soil sampling along the perimeters of ornamental flower beds and sun-exposed slopes, as female May beetles preferentially oviposit in warm, well-drained soils.

Step 2: Deploy Biological Controls for Subterranean Grubs

Incorporate living microscopic organisms to suppress the grub population without chemical runoff. Apply entomopathogenic nematodes or Bacillus thuringiensis galleriae (Bt) directly to moist soil during early autumn when young grubs are small and voracious.

1. Water the lawn thoroughly with one inch of irrigation immediately before application to soften the soil profile.
2. Mix beneficial nematodes into a standard hose-end sprayer, keeping water temperature between 60°F and 85°F to prevent thermal shock.
3. Apply the solution during early evening or overcast conditions, as ultraviolet radiation rapidly degrades biological agents.
4. Irrigate again post-application to wash the nematodes down through the thatch layer directly into the root zone where grubs reside.

Warning: Never use chemical synthetic fertilizers or broad-spectrum fungicides simultaneously with biological nematode treatments, as chemical residues can kill beneficial nematodes before they locate host grubs.

Step 3: Implement Mechanical Trapping for Adult Beetles

Adult May beetles are heavily attracted to artificial light sources during their nocturnal flight hours in late spring. Exploit this phototactic behavior to drastically reduce the breeding population before they lay their next generation of eggs.

1. Construct a simple trap by placing a bucket filled with water and a few drops of liquid dish soap beneath an isolated floodlight or porch light.
2. Turn on the light source at dusk when adult beetles begin emerging from the ground.
3. Inspect the bucket each morning, collecting and disposing of drowned beetles.
4. Move permanent landscape lighting further away from delicate garden plants to redirect flying adults away from vulnerable foliage.

Step 4: Apply Long-Lasting Preventive Chemical Barriers

If biological methods fail to curb severe infestations, apply targeted systemic insecticides precisely timed with regional hatching cycles. Chlorantraniliprole provides extended residual control with minimal impact on non-target pollinators when applied correctly.

1. Calibrate your rotary broadcast spreader according to the granular insecticide manufacturer specifications.
2. Apply systemic granules uniformly across the turfgrass canopy in early summer just as adult beetles finish mating and eggs begin to hatch.
3. Water the treated lawn immediately with 0.5 inches of water to activate the active ingredients and bind them to the soil particles.
4. Keep pets and children off the treated turf until the granules are completely dissolved and the grass blades dry entirely.

Treatment Methods Comparison Matrix

Common Site Failures and Field Fixes

• Failure: Nematode application yields zero population reduction.
  
  
  • Root Cause: Soil temperatures dropped below 50°F during application, or nematodes were exposed to direct sunlight, causing rapid desiccation and mortality.
  • Actionable Fix: Reapply nematodes only when soil temperatures range consistently between 60°F and 85°F, and strictly execute applications at dusk followed by heavy irrigation.
• Failure: Grubs survive systemic insecticide treatments.
  
  
  • Root Cause: Failure to water the granules into the root zone, leaving the active ingredient trapped in the thatch layer above the feeding zone.
  • Actionable Fix: Apply a thorough irrigation cycle of at least 0.5 to 0.75 inches of water immediately following granular or liquid chemical distribution.
• Failure: Turf continues to die back despite eliminating grubs.
  
  
  • Root Cause: Secondary damage from scavengers such as skunks, raccoons, or crows tearing up the sod in search of remaining grubs.
  • Actionable Fix: Temporarily cover damaged lawn sections with lightweight garden netting or apply organic animal repellents until the turf root system recovers.

Frequently Asked Questions

What causes May beetle infestations in lawns?

May beetles are attracted to over-watered, lush turfgrass with thick thatch layers, which provide optimal moisture and shelter for female beetles to lay eggs. Improper mowing heights and excessive nitrogen fertilization can also create an inviting habitat for adult beetles seeking soft soil.

Do May beetles bite or sting humans?

No, adult May beetles possess chewing mouthparts designed exclusively for foliage and do not bite or sting humans. They are completely harmless to people and pets, though their erratic, clumsy flight patterns can cause accidental contact.

When is the best time of year to treat for grubs?

The most effective treatment window is late summer (August through September) when newly hatched grubs are small, feeding near the surface, and highly vulnerable to biological and chemical controls. Spring treatments are generally ineffective because mature grubs are deep in the soil and have stopped feeding before pupation.

Can beneficial nematodes completely eliminate a May beetle problem?

Beneficial nematodes can significantly reduce grub populations by up to 60% to 80% when applied under optimal soil moisture and temperature conditions. However, total eradication is rarely achieved in a single season, requiring continuous annual monitoring and integrated pest management practices.

Protect Your Landscape Today

Take control of your lawn’s health today by identifying early signs of grub activity and applying targeted biological treatments before minor pests escalate into major turf destruction. Start your comprehensive inspection this weekend to ensure a lush, resilient, and beetle-free landscape all season long.