Learn Your Lawn: White Grubs

What Are White Grubs?

White Grubs are the larvae of certain species of beetles, such as the Japanese Beetle, June Beetle, and European Chafer. These grubs are common pests in residential lawns, particularly in North America. White Grubs are typically white or cream-coloured, with a C-shaped body that is about 1 inch long. They are also easily identified by their brown head and three sets of brown legs.

White Grubs feed on the roots of grass, which can cause extensive damage to the lawn. Infestations are most common in lawns that have been recently established or those that have thin or weak turf. They pupate and emerge as adult beetles to lay their eggs in late spring and are most active in the late summer and early fall when they are feeding and growing.

Signs of infestation include dead or dying patches of grass, loose turf, and birds or other animals digging in the lawn to feed on the grubs. Secondary damage from skunks and raccoons is usually the strongest indicator of a grub problem. Unfortunately, we are not able to prevent this damage, which makes a proactive approach for treatment even more important.

What Is The Life Cycle Of A White Grub?

The life cycle of White Grubs can vary somewhat depending on the species, but in general, it consists of four stages: egg, larva, pupa, and adult. Although the adult beetles do not cause damage to the lawn, an increased population of the adult beetles in your area can be an indicator of a problem to come in fall.

• Egg Stage: Female beetles lay their eggs in the soil during the summer months. The eggs hatch within two weeks, and the larvae emerge from the eggs.
• Larva Stage: The grubs live in the soil and feed on the roots of grasses and other plants. This stage can last anywhere from a few months to a few years, depending on the species and the environmental conditions.
• Pupa Stage: During this stage, the White Grub transforms into an adult beetle. The pupa is usually located deep in the soil, and the transformation from larva to adult can take several weeks.
• Adult Stage: Once the beetle has fully developed, it emerges from the soil and begins its adult life. The adult beetles mate and lay eggs, starting the cycle all over again.

How Can I Control White Grubs In My Lawn?

Serious damage can occur in spring and fall. The damaged patches will get larger and can devastate a lawn in a short period of time. Understanding the lifecycle of White Grubs is important for managing their populations and preventing damage.

A thick, healthy, well-maintained lawn is always the best line of defense. This can be achieved through beneficial cultural practices, which include:

• Watering: Deep and infrequent watering is essential for strong plant health and development. A general rule of thumb is to water each area of your lawn for 30-45 minutes, twice per week, in the early morning so the turf is dry by nightfall. 

• Mowing: Maintain a regular mowing schedule throughout the growing season. In general, you should keep your lawn between 2 ½ and 3 ½ inches high, but during the hottest weeks of summer, you may allow the grass to grow as high as 4 inches. Never remove more than ⅓ of the grass blade at each mowing.

• Fertilizing: Regular applications of Weed Man’s specially formulated, slow-release granular fertilizer will help provide your lawn with adequate nutrients. These applications are timed specifically to avoid over fertilizing the lawn.

• Core Aeration: Aerating your lawn can improve soil drainage and help reduce the likelihood of insect infestations. It will also alleviate soil compaction and allow water and nutrients to penetrate deeper into the soil.

Your local Weed Man professional may be able to offer other solutions and recommend the best form of treatment that is available to improve the conditions of your lawn.