Best Organic Grub Control: Milky Spore — One Application That Kills Japanese Beetle Grubs for 10–15 Years Buy on Old Cobblers Farm
Chemical grub killers work for one season. Milky spore establishes a living biological population in your soil that infects and kills Japanese beetle grubs for 10–15 years from a single application. The grubs eat the spores, die, and release billions more spores — a self-perpetuating cycle of control.
Old Cobblers Farm™ Wicked Organics Milky Spore
by Organic Fertilizer — Littleton, NH
Living Biological Control
Milky spore is a living bacterium (Paenibacillus popilliae) — not a chemical. It infects Japanese beetle grubs from inside, turning their body fluid milky white as spores multiply, then killing them.
Self-Perpetuating — Gets Stronger
Each infected grub releases 1–2 billion new spores into the soil when it dies. The spore population grows with each generation of grubs — control improves year after year.
10–15 Year Protection
Once established, milky spore populations persist for 10–15 years without reapplication. No other grub control product provides anything close to this duration.
Targets Only Japanese Beetle Grubs
Milky spore is species-specific — it only infects Japanese beetle larvae. Earthworms, beneficial insects, pets, children, and all other organisms are completely unaffected.
Water In to Activate
Apply and water in within 15 minutes to move spores into the soil profile where grubs feed. Soil temperature of 60–70°F is ideal for fastest establishment.
No Chemical Grub Products
Chemical grub killers (like GrubEx) kill the same grubs milky spore needs to multiply. Treat the entire lawn and avoid chemical grub products for milky spore to establish.
100% Organic & Non-Toxic
Safe for children, pets, wildlife, waterways, and all non-target organisms. No chemicals, no toxins, no environmental concerns. The safest grub control available.
Trusted by 20,000+ Growers
Developed in Littleton, New Hampshire. Sold nationwide on Amazon, Walmart, eBay, and theoldcobblersfarm.com.
| Item Form | Powder |
| Coverage | 2,500–7,000 sq ft per application depending on method |
| Category | Organic Fertilizer |
| Type | Soil Amendments |
| Sizes | 10 oz | 20 oz | 40 oz |
| Active | Paenibacillus popilliae (milky spore) |
| Type | Biological grub control |
| Target | Japanese beetle grubs only |
| Rate | 1 tsp / 4 ft grid or 10 oz / 2,500 sq ft |
| Method | Apply and water in within 15 min |
| Application | ONE-TIME (or 3x/yr for 2 years) |
| Duration | 10–15 years |
| Sizes | 10 oz, 20 oz, 40 oz |
| Note | Do NOT use chemical grub products — they kill the grubs milky spore needs |
| Feature | Old Cobblers Farm™ Wicked Organics Milky Spore Old Cobblers Farm | Milky Spore Powder St. Gabriel Org | Milky Spore Granule St. Gabriel Org | Season Long Grub BioAdvanced | GrubEx1 Scotts | Organic Grub grubGONE! | Beneficial Nematodes NemaSeek | Garden Insect Spray Monterey | Captain Jack's Bonide | Grub Control Natria | Lawn Restore Safer Brand |
|---|---|---|---|---|---|---|---|---|---|---|---|
| NPK | Biological | Biological | Synthetic | Synthetic | Biological | Biological | Biological | Biological | Biological | 9-0-2 | |
| Form | Powder | — | — | — | — | — | — | — | — | — | — |
| Coverage | 2,500–7,000 sq ft per application depending on method | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed |
| Price / Size | 10 oz | 20 oz | 40 oz | $34.99 | $49.99 | $29.99 | $39.99 | $47.00 | $40.00 | $32.59 | $10.97 | $12.99 | $44.99 |
| Our Take | The only grub control product that gets stronger over time instead ... | — | — | — | — | — | — | — | — | — | — |
Milky Spore Powder
Milky Spore Granule
Season Long Grub
GrubEx1
Organic Grub
Beneficial Nematodes
Garden Insect Spray
Captain Jack's
Grub Control
Lawn Restore
Living Biological Control
Milky spore is a living bacterium (Paenibacillus popilliae) — not a chemical. It infects Japanese beetle grubs from inside, turning their body fluid milky white as spores multiply, then killing them.
Self-Perpetuating — Gets Stronger
Each infected grub releases 1–2 billion new spores into the soil when it dies. The spore population grows with each generation of grubs — control improves year after year.
10–15 Year Protection
Once established, milky spore populations persist for 10–15 years without reapplication. No other grub control product provides anything close to this duration.
Targets Only Japanese Beetle Grubs
Milky spore is species-specific — it only infects Japanese beetle larvae. Earthworms, beneficial insects, pets, children, and all other organisms are completely unaffected.
