Apply trichlorfon (Dylox) as curative if grub count exceeds 5 per sq ft

What to Do

If grub counts exceed 5 per square foot, apply trichlorfon (sold as Dylox or Bayer 24-Hour Grub Killer) immediately. Water in heavily — at least half an inch — within 24 hours of application to move the product into the root zone.

Why It Works

Trichlorfon is one of only two curative grub treatments (along with carbaryl) that kill grubs already feeding in the soil. MSU Extension research shows it kills 20-80% of grubs when applied in fall, and 20-55% in late October. It works within 24-48 hours of contact, unlike preventive products that take weeks.

Tips

• Curative products are less effective than preventive ones — prevention with chlorantraniliprole is always the better strategy.
• Trichlorfon has a short residual and breaks down quickly in the environment.
• The heavy watering requirement is critical — without it, the product stays on the surface and does not reach the grubs.