Identifying White Grubs in Your Iowa Lawn

white grubs iowa lawns

There are numerous insects and weeds that can affect a stand of turfgrass, whether it be a home lawn, a golf course, or an athletic field. They all are unique in their timing, damage, and what we can do to control them. Few things, however, can take out a vast area of turf like white grubs can. One infestation of white grubs is all that is needed to know that they are something worth treating for. If you haven’t had them in your lawn, the odds are that you know someone who has. We’ll look at how to identify them, the damage they cause, and what can be done to control and prevent them.

What Does White Grub Damage Look Like?

White grubs are the larvae of several types of beetles. These adults lay eggs in the summer, and these eggs hatch in the early fall. These larvae are really hungry and need to eat a lot in order to prepare for overwintering and metamorphosis (when they change into adults). They eat the roots of turfgrass right below the surface of the soil, causing the plants to dry out, wilt, and eventually die. Labor Day is usually when we start to see grub damage, and it can persist into October. If grubs are suspected, there’s a very easy way to find out. When the turf is grabbed and pulled, it peels back like carpet (as shown on the left). The picture on the right shows grub damage a few days after infestation.

This damage in and of itself is incredibly damaging. What can be absolutely devastating, however, is the damage caused by animals looking for these grubs. Skunks, raccoons, possums, and other four-legged friends will turn the grass over and dig to find these grubs. That damage is pictured above on the left and below. These animals are all nocturnal, so they’re doing their feeding at night. We can repair that damage by putting everything back down in its place, but if there are still grubs in the soil, the same areas will unfortunately be dug up again. Once the turf is put back, it will take fertilizer and a healthy amount of water to get things to root and fill in again. It is not an enjoyable process. In most cases, areas that have been damaged by grubs eventually need re-seeded or sodded.

White Grub Identification

White grubs are the larvae of several different beetles that are common in this area of the country. As the name suggests, they have a white, fleshy body and an orange/brown head. They have three pairs of very small legs near their head with an elongated body. They are usually found curled up in the shape of a “c”. There are nine different insects that give rise to white grubs. The most common in our area that lead to white grubs are the Northern Masked Chafer and Japanese Beetle. The bluegrass billbug is also a culprit, but their timing is different and that is discussed in another blog post. Here is a picture of the different beetle species, and a picture of the various grubs that hatch from these adults. They all have the same general appearance but are different in their size and the pattern of the hairs on their hind end.

Controlling White Grubs

Luckily, white grubs can be controlled with a single application in the summer. There are a few different insecticides that can be applied to turf that will make the roots toxic to these grubs. The product that we use at UltraLawn is applied in the summer when adults are in flight and laying their eggs. This will need watered in so the plant can fully absorb the active ingredient. Preventative measures are the best, most economical way to treat for grubs by a wide margin.

Curative measures are available if an infestation has occurred. The active ingredients to these products are different, and they are typically more expensive. In order for these products to work, they need to be thoroughly watered in immediately after application for the product to work its way through the turf down to the grubs. Even if the response is prompt and the product is properly applied and watered in, there is no guarantee that our animal friends will stay away. Depending on how hungry they are, they may still eat grubs that are dead.

Grubs are the most damaging pest to bluegrass, and in order to protect your lawn, they must be treated for accordingly. If you would like some assistance, please contact us here at UltraLawn. Our trained professionals will gladly help!