Where Do Grub Worms Come From? [Grub Worms Lifecycle]

Grub worms, known as lawn grubs, are pesky insects that live under your lawn. These lawn grubs look like maggots, but grubs are a lot bigger and thicker than maggots.

In reality, these grub worms are the larva of Japanese beetles that feed on plants’ roots. You might wonder, since they are not harmful to us, their existence will not bother you. These pesky insects living under your lawn might not sound like a problem until you find out they are destroying your lawn.

What are grubs?

 grubs worms

Grubs or Phyllophaga are the larval forms of the famous Japanese beetles. Among all other beetles from the beetle kingdom, grubs are the most troublesome insects.

Grubs are white and have dark spots around their legs. Grubs are wrinkly and mostly one inch in length. Grubs can be found under your lawn. Mainly under the area where the ground is raised from its surroundings. While walking in that area, you will feel the soil beneath your feet is bouncy. 

Grubs tend to harm your lawn while leaving and feeding under it. Grubs feed on the roots of plants while being the reason for the death of your plants. Luckily grubs are easy to deal with when you notice beforehand any major damage.

Where do grub worms come from?

When Japanese beetles roam around your trees during the summer, the female beetles are ready to lay their eggs. Although beetles live on trees, they don’t lay eggs on trees. Instead, female Japanese lay their eggs under the soil.

The female beetle lays her egg under your lawn since the lawn provides the best place for Japanese beetles. Grub worms use your lawn as shelter and get a good amount of food sources. At a time, female beetles can lay about 40 eggs. These eggs will hatch within a few weeks and be ready to feed on the root of your plants. 

What attracts grubs to your yard?

Two things can bring grubs to your yards. They are shelter and food. 


A good and reliable shelter is a must for worms. They provide a suitable place to live and hatch into beetles and protect grubs from predators like moles and birds. After the female lays eggs under the soil, grubs make your lawn suitable for living.

Your lawn will supply them with unlimited food sources because grubs feed on the roots of dead plants. During winter, grubs can go deeper into the ground and save themselves from cold temperatures. 


Food is important for survival, and in the wild finding, food can be challenging. But luckily, grubs can get unlimited access to food under your lawn. The eggs hatch during summer and turn into grub worms.

After the grubs are hatched, they need food and during summer, many dead plants become their food sources. 

What is the grub worm life cycle?

There are four life cycle stages for a grub, starting from an egg, larvae stage, pupa, and adult beetle. 

Egg stage

It is during summer when a grub hatches from its egg. Female beetles generally lay eggs inside holes around June and August. The eggs can hatch in one or two weeks in healthy and warm conditions. 

Larva stage

After grubs hatch from eggs, their feeding session starts. Summer is the best time for feeding as there are plants that die due to excessive heat. Grub will feed on them. Grubs cause no threat to humans but only for plants. As they feed on plants, they move on to the next stage.

Pupae stage

Once the feeding session is over grubs are ready to go into the pupae stage. During this stage, the pupae will stay inside the soil and use its string to form a cocoon. It will take a few weeks to finish this stage and go into the last stage of development.

Pupae will take a few weeks; during this period, the pupae will grow faster than usual. The last type of beetle you would want coming out of your lawn is the Japanese beetle, which has become a headache for landowners. 

Adult beetles 

An adult beetle will emerge from your ground at the beginning of summer. Once they emerge, they are ready to mate within a few days so that the female grubs are prepared to lay 50-60 eggs all over your lawn. The whole life cycle of a Japanese beetle is about a year, whereas June beetles have a life cycle of three years. 

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people also ask (FAQs)

Do coffee grounds attract grubs?

Yes, coffee grounds attract grubs. Many gardeners use coffee grounds as fertilizer, but unfortunately, this can attract unwanted grubs. Grub worms love to eat coffee grounds, and they will soon take over your lawn.

Coffee grounds are natural ways to prevent snails and slugs from entering your field. Coffee grounds also have toxins that are harmful to many insects. Using coffee grounds on your lawn could repel insects like mosquitoes, flies, beetles, and many other pests. 

Will grub-damaged lawn grow back?

Yes, the grub-damaged lawn will grow back with time. Grubs can be devastating for your lawn if not dealt with early on. Grubs will lay eggs during early summer, and soon the eggs will hatch. It can be hard to find such areas over the vast ground but if you do, take immediate action.

At some point, you will notice a bump on your lawn, and it is a clear indication that there are grubs

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Grubs are interesting living creatures, but many people don’t like them because they can damage your environment. There is not much benefit these creatures can do to you; they certainly don’t like creatures you would want to keep as a pet.

And this brings us to the conclusion of getting rid of these pesky insects while we still can. It is not that hard to get rid of them.

All you need is some basic compounds already available in your house underneath. Lawn destroyed by grubs can be fixed, and in some cases, you might need to do over your lawn which can be expensive, but your lawn will return to normal. 

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