FAQ: How to Kill White Grubs with Nematodes

August 3, 2016 | Common Garden Pests

White grubs are a very common insect pest. Not only do the grubs cause damage to turf and lawns, but adult beetles can also cause damage to a wide variety of plants. Now is the perfect time to treat with nematodes to kill white grubs in preparation for next spring!

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Question: What are white grubs and how do I know if I have them?

Answer: White grubs are the larval stages of a wide variety of scarab beetles including Japanese Beetles, Northern Masked Chafers and Rose Chafers. White grubs feed on plant roots causing patches of dying, brown grass. A bad infestation can cause grass or turf to be so damaged it can be pulled back like a carpet.

Question: Which product do you recommend for treating white grubs?

Answer: Heteromask is our preferred product for white grubs, but Scanmask is also effective.

Question: When can I treat for white grubs?

Answer: Since almost all scarab beetles have a life cycle of one year, it is important to treat at the right time to ensure the nematodes can kill the larvae and prevent new adults from emerging. Treating in late summer or early fall is ideal, as that is when the smaller, young grubs are most susceptible to nematodes. There is also usually a short window for application in early spring before the grubs get too big and pupate.

Question: How many nematodes do I need for my grub infestation?

Answer: We recommend about 25,000 nematodes per square foot.

Question: How should I apply the nematodes?

Answer: Focus treatment on sunny areas of your lawn/turf or on any areas that show signs of grub damage.  Heteromask comes in a spray formulation, and you can use the Nema-Jet, a hose end sprayer or a watering can (for smaller areas) to apply. We include detailed directions with our products, or you can view the full directions on our website.

Question: How often do I need to apply?

Answer: Treat once/year.

Question: Are nematodes safe to use around children? Will they harm my fish, bees, earthworms or any other beneficials?

Answer: The nematodes in BioLogic’s products are naturally occurring and completely safe for people, pets and plants. They are environmentally friendly and non-toxic. They pose no danger to humans, and you do not need to worry about run-off. They are compatible with other beneficials like earthworms, ladybugs and praying mantises!