Natural Lawn Grub Control


Natural lawn grub control
Male blackbird with caterpillar and juicy grubs in its beak. Close-up of garden bird collecting insect food for its young chicks. Parent bird foraging for food on grass lawn in the UK.

Every lawn owner hates the term “White grub in the lawn” for they know that if left untreated, the lawn grub/white grub will destroy every blade of grass and the owner will end up with no lawn.

However, to get rid of lawn grub, a person has to be aware of three things:

A) The life cycle of the lawn grub
B) How to keep the lawn grass healthy so that it cannot be totally destroyed by lawn grub, and
C) How to get rid of the lawn grub/white grub by using a perfectly natural enemy which is eco-friendly and easy to apply

A. The Life Cycle Of A Lawn Grub/ White Grub

Lawn grub
Image Credit:

According to Wikipedia, “lawn grubs or white grubs or grubworms are the larvae of scarab beetles”. These beetles are usually “June bugs”, but some of these scarab beetles might be Japanese Beetles and every few years there is a population peak of European Chafer Beetle.

The Beetle’s Life Cycle Explained

Let’s briefly consider the beetle’s life cycle. The beetle lays her eggs in the soil during the June/July months. Then by August, the eggs have hatched, and the resulting grubs begin feeding on grass roots until about October when they begin their journey down deeper into the soil where they will overwinter.

Beetle life cycle

By January each lawn grub begins its journey back up towards the surface where it can start feeding on roots again. Around May each grub (the larvae) turns into a pupa which in turn emerges as a beetle in June. (I understand the June beetle larvae does 3 years underground before emerging as a beetle.) Soon the beetle is ready to lay its eggs to begin a “new generation” of lawn grub or grub worms.

It’s obviously very important to CAREFULLY MONITOR your lawn in April/May and again from August onward especially if there is a dry spell. The dryer and weaker the lawn, the better the lawn grub likes it.

Better yet, why not protect your lawn by spraying it with nematodes before the grubs get a chance to taste your lawn’s roots? You can apply the product in spring and fall. See the explanation in the section below on how easy it is to apply the nematodes to your lawn.

B. How To Build Or Rebuild Your Lawn So That The Grass Roots Are Strong, Healthy, And Not Easily Destroyed By Lawn Grub?

Of course, by the time you see lawn grub damage in your lawn, it is too late to correct the problem for the year. The grubs have already eaten your grassroots. However, you can concentrate on next year’s lawn and begin repairing the damage as follows:

1. Begin by overseeding your lawn.

2. Reduce Your Use of Artificial Fertilizers.

The presence of a lot of grubs means you have an unhealthy lawn. Nearly always, the grubs are enjoying your grassroots because they are weak and soft…caused by using too much fertilizer and probably the type that has a high nitrogen number.

“Green up” fertilizers, particularly liquid ones, force the grass to grow far faster than it would naturally. Local organic turf specialists use far less nitrogen than is recommended on most fertilizer bags.

The solution is to mow high, often and lightly, and leave the clippings on the lawn. Healthy soil with nutrients released slowly by decomposition lets roots grow slowly and steadily all year thereby producing strong roots. So these clippings are the best slow-release fertilizer there is for your grass.

3. Water no more than once a week, but water deeply.

TIP: When watering, put a container on your lawn, and don’t stop until there is at least 2.5 cm (about 1 inch) of water in it. For most sprinklers that takes a full hour. Also, check to make sure the water has penetrated the soil to a depth of 6 to 8 inches minimum.

4. You might consider putting up a nesting box for starlings because they raise their young on white grubs. With their beaks, they make only tiny holes in the turf to get them.

5. Final and best step to take is to put some nematodes into your lawn.

C. Nematodes, A Natural Predator Of The Lawn Grub, To The Rescue

Nematodes can usually be found in an environmentally friendly nursery. They may be somewhat expensive but are worth every penny.

To find a nursery near you, Google as follows: nematode + nursery + (name of your city/state)

What are nematodes?

Nematodes are microscopic worms that are normally found in the earth. Certain ones love to feed on the leather jacket while others love to feed on white grubs.

The nematodes enter the lawn grub (which is the living larvae of a beetle) and release bacteria that kill the larvae. Then the nematodes reproduce inside the dead larva and later thousands of new nematodes leave the larva in search of further prey.

What do nematodes seek out?

Nematodes seek out lawn grubs otherwise known as white grubs, citrus root weevils, the Japanese beetles, the May/June pupa of the beetles, the European/Masked chafer, the black vine weevil, and the sod webworm.

How do you use the eco/environmentally-friendly product?

In the nursery, these nematodes are kept alive in a fridge, so when you buy them you should spray them on your lawn as soon as possible.

Spraying nematodes is quite easy to do. There are 3 easy steps to follow.

First, you water the lawn;

Secondmix the nematodes (as per the instructions on the container) in a special sprayer with somewhat larger holes than in a normal sprayer to allow these tiny worms to come out with the water.

Third, you attach the sprayer to your hose and spray. The application must be done in the early evening or on a cloudy day and the lawn must be kept moist for a minimum of 3 days.

PERSONAL COMMENTS: My experience with nematodes and lawn grub

I used nematodes on my lawn back in the 1990′s.

I’ll always remember that spring when I had to use the nematodes. I happened to be edging the flower bed adjoining my lawn when suddenly I brought up a shovelful of lawn only to discover that my lawn was infested with grubs.

I started investigating and found that no matter where I used my shovel to check, I would find these grubs. They were all over the lawn. I panicked! I had become somewhat environmentally more careful, so I did not want to spray insecticide on my lawn. What to do?!?

I went to the only nursery I knew had other than insecticides to offer, and that’s where I learned about the nematodes. I had a large front yard, so I had to get two batches. Fortunately, after spraying in the nematodes, I never again had to deal with lawn grub in my lawn. Needless to say, I was happy I had found an eco-friendly way in which I could get rid of lawn grubs forever.