Grubs can become a nuisance in lawns and gardens, eating the roots and bulbs of grass and flowers, causing damage and leaving plants susceptible to moisture stress. As grubs complete their life cycle in early to mid-June, they transform into beetles that cause additional harm by eating ornamental flowers and bushes. Traditional insecticides are most effective as a preventative measure only. If your garden is infested with grubs, you will need to use alternative control methods.
Spread milky spore granules over the infested area at a rate of 1 teaspoon for every 4-by-4-foot square. Water the area well to encourage settling. Milky spore is a bacteria that kills grubs but leaves other organisms unharmed. Do not apply repeat applications of milky spore; one application can last between 25 and 40 years.
Add the contents of a packet of beneficial grub nematode to a 5-gallon bucket of water and stir to break up any clumps. Allow the solution to soak for 3 to 5 minutes. Pour the nematode solution into a spray bottle or water can. Spray or pour the solution evenly over the infested area, continually mixing the solution to prevent the nematodes from sinking to the bottom. Apply nematodes in the early evening when soil temperature has decreased. Beneficial nematodes will not harm humans, plants or animals, but will aggressively attack insects like grubs.
Keep the soil well-watered for 1 week after nematode application to help them establish, as nematodes require moist soil to thrive. Two weeks after application, water and fertilize your garden as usual to assist in repairing grub damage and providing the flowers with nutrients to regrow.
Things You Will Need
- Milky spore
- Grub nematodes packet
- 5-gallon bucket
- Though nematodes can be kept in the freezer for up to 1 month before use, it is best to apply them as soon as you receive them.
- Do not fertilize infested area from 2 weeks before to 2 weeks after nematode application, as nematodes can be harmed by high levels of nitrogen.