Grub Control — Prevention & Treatment

Preventive vs. Curative

There are two fundamentally different approaches to grub control, and timing determines which one you need.

Preventive (chlorantraniliprole / GrubEx): Apply when GDD reaches 300-500 (typically late spring). This kills grubs as eggs hatch in summer. It does NOT kill active grubs. Must be watered in with 0.5 inches of irrigation.

Curative (trichlorfon / Dylox): Apply August through October when you can see active grub damage (spongy turf that peels back like carpet). Soil must be above 50°F. Works within 24-48 hours.

Timing by GDD

Do NOT use calendar dates for preventive grub control. GDD 300-500 is the reliable trigger. This typically falls in:

• Zones 3-5: Late May to mid-June
• Zones 6-7: Mid-May to early June
• Zones 8-10: Late April to mid-May

Product Recommendations

Scotts GrubEx (chlorantraniliprole) is the community consensus pick for prevention. It is bee-safe (important for pollinator protection) and provides season-long control with a single application.

For active infestations, BioAdvanced 24-Hour Grub Killer (trichlorfon) is the fastest-acting curative option. Apply in the evening, water in immediately.

The Diagnostic Test

Before treating, confirm you actually have grubs. Cut a 1-square-foot section of turf and peel it back. More than 5 grubs per square foot indicates treatment is needed. Fewer than 5 is normal and does not require treatment.