The larvae or grubs of June Beetles/ May Beetles cause extensive damage to the roots of lawns and shrubs. June Beetles are sometimes called "May Beetles" in certain parts of the country. The name merely designates which month of the year that the adult beetles are known to emerge from the soil. This page contains information to help you understand the June Beetle and their grubs that destroy grasses of lawns, golf courses and pasture lands. Topics covered include biology of the bug, lawn grub damage and control of white grubs (the name used to cover the larval stages of destructive beetles such as June Beetles, Japanese Beetles, Chafers and others.) An understanding to the life cycle of this insect will be of importance to those responsible for its elimination and control. If grub pest control methods are not timed properly, time and money will be wasted. The timing of insecticide application, type of insecticide to use as well as very important cultural practices will all be covered in the grub control section.

General June Beetle Biology June Beetle Damage to Lawns Grub Control

General June Beetle Biology

As mentioned at the beginning of this article, a May Beetle is the same bug as the June Beetle. The month that the adults are seen as they emerge from their pupal cells usually designates what locals call the pest in their part of the United States. (These beetles are called Junebeetle, June beetles, June Bugs but their proper name is June Beetle)
Knowledge of when the adult beetles are mating and depositing eggs in the soil will be of the utmost importance for determining when insecticides should or should not be applied to lawns and around shrubs.

What we consider a typical June Beetle can vary in color from pale yellow to black but most are brown to dark brown. The Green June Beetle has a different appearance but its damage to lawns in its larval stage is similar to other white grubs and is controlled in the same manner. The adult beetle is known as a night flyer. The Japanese Beetle (another pest whose grubs damage lawns) is a daytime flyer.

Depending on the particular species, area where it breeds and environmental conditions, the June Beetle can have a cycle that is short as one year or up to four years. While inspecting lawns for grubs of this pest, people often report seeing various sizes of grubs beneath their turf grass. This is caused by over lapping generations of immature beetle grubs that can take 3 to 5 years to complete their cycle.
Mated female beetles make intermittent trips from plant foliage to the soil. After feeding on leaves of plants she will dig into nearby soil where she lays her eggs. These eggs hatch in two to three weeks, depending on environmental conditions and species involved. The larvae that hatch from these eggs are commonly called white grubs, the same term used for Japanese Beetle grubs.

The white grubs of the June Beetle are C-shaped when they are at rest. This C shape appearance is common of White Grubs. The newly hatched grubs are too small to feed on the major root system of plants but they are capable of eating organic materials in the soil and (as they grow larger) the smaller hair roots of plants.
When cooler temperatures arrive, the beetle grubs begin to dig deeper into the soil where they are protected from frigid winter weather. As warmer weather approaches the grubs end their hibernation and return to more shallow depths where they again feed on roots of grass and shrubs. Depending on the exact species, the grubs will either pupate or continue the cycle through another winter. Once pupation is complete the adult June Beetle emerges from the soil. In this manner, the cycle and re-infestation of the pest in lawns and landscape shrubs continues.

June Beetle Damage to Lawns

As roots are damaged by feeding and tunneling, the grass will begin to show signs of stress. Yellowish tinges may appear in otherwise green grass. When infestations are heavy, the turf grass can be rolled away from the ground much as one would roll up a carpet or rug. During seasons of heavy rain or constant irrigation, above ground leaves of grass may not always fade out but these sections will be easily seen the following spring - when the areas do not green up with the rest of the lawn.

Grub Control

Control of White Grubs in Lawns

Insecticide applications should be applied in mid June to July in most areas. This timing might be different in your area. You want your insecticide to attack grubs in their first instar, while they are young, small and close to the surface. If you observe June Beetles depositing eggs in the soil, you can gauge the timing of insecticide application. As mentioned above, grubs emerge from their eggs about 3 weeks after eggs are deposited into the soil around shrubs and in lawns.

The timing of grub control products is important but is easier than in years past. New, systemic insecticides such as professional strength Merit Granules can help broaden the window of application by several days. This systemic insecticide can give season long control and it can easily stay active in the root system of plants for about 3 months.

For more information, go to White Grub Control and Merit Systemic Insecticides.

Japanese Beetles Lawn Pests Household Pests Merit Insecticide

June/ May Beetles