Japanese beetles are quite active right now in Shelby County and throughout the Mid-South. These severely damaging insects generally show up in our landscapes in mid-June and can be around into August. They not only feed on some of our most precious plants, they also live in the soil as grubs, posing an even larger problem for those who enjoy a well-manicured lawn.
Adult Feeding Behavior
Adult Japanese Beetles have a ravenous appetite. They eat almost everything in their path, including one of their favorites: roses. You can easily tell when they have been in your yard by the telltale eating pattern they leave behind. Foliage decimated by the Japanese Beetle has a lace-like look, with most of the green foliage gone and only the veins remaining.
They move in swarms, and once they begin to feed, they give off a scent that calls the rest of the colony to the dinner table. Unlike most beetles, the Japanese Beetle feeds during the day in full sunlight, where their almost iridescent copper-colored wing covers shine. Fortunately, their lifespan is only about 45 days. Egg laying begins soon after the adults emerge from the ground and mate. Females leave the plants in the afternoon and burrow 2 to 3 inches into the soil to lay their eggs, a total of 40 to 60 during their short lifespan. Because these beetles are highly mobile, the only way to protect your plants is to spray regularly.
Controlling Adult Beetles
Products that have proven effective include:
- Bonide Eight containing Permethrin
- Ferti-Lome Broad Spectrum Insecticide containing Bifenthrin
- Hi-Yield Systemic Insect Spray containing Imidacloprid
- Bonide Systemic Insect Control containing Acephate
- Captain Jack’s Dead Bug Brew containing Spinosad
Hanging a Japanese Beetle trap also reduces the beetle population in the area by the hundreds over a short period of time and potentially prevents or minimizes damage to other areas. Stop in and we will be happy to assist you in determining the best control for your landscape.
Grubs: The Underground Problem
After the female lays her eggs, they hatch in a very short gestation period into the larva stage, known as grubs. These grubs begin to feed on the tender root systems of our lawns. There is no favorite grass type, so all Mid-South grasses are susceptible to grub damage. Grub damage appears as an irregular brown spot in the yard that grows at a steady rate. When the root system is damaged or gone, the grass dies very quickly.
The secondary problem with a high number of grubs in your soil is moles. Grubs are a primary food source for moles, and once they find a good place to feed, they can turn your manicured lawn into what closely resembles a war zone. Moles rarely venture above ground, so conventional small-animal traps and baits are useless. In-ground traps and baits are hit and miss, and repellants are not 100% effective. Removing the food source before moles venture into your yard is the best approach, since their only reason to be there is to feed.
Controlling Grubs
Knowing the life span from hatching to adulthood is the key to keeping grubs under control. When grubs first hatch, their first instinct is to feed. Treating your lawn with a systemic insecticide like Hi-Yield Grub Free Zone II containing Imidacloprid is your best chance to knock back the grub population to acceptable levels.
Grubs will continue to increase in size until fall, when dropping soil temperatures force them to burrow deeper into the soil for warmth. In spring, when soil temperatures begin to rise, the grubs return to the surface to feed on grass roots again. About 14 days before emerging from the soil as a beetle, the grub enters a pupae stage and stops feeding.
The best product to kill grubs in the fall, before soil temperatures drop, is Bayer Grub Killer containing Dylox. This product can also be used in the spring when the soil temperatures rise and the grubs come back to the surface. Timing and selecting the correct treatment is critical to controlling damaging grubs in your landscape.