When we think of lawn pests, we often think of unwanted visitors like deer, raccoons, and rabbits, who have an uncanny way of sneaking in and munching away on our landscapes, leaving only nubs, missing, and misshapen plants as evidence that they’ve been there.
But there are quite a few more unwanted guests happily munching away at your lawn. Much smaller than those four-legged visitors, bugs often eat away undetected. One of the worst that local homeowners deal with at this time of the year is the grub.
There’s a reason why grubs have some of the biggest appetites in the insect kingdom. The collective term “grub” simply refers to a bug or insect that is still in its larval stage. The grubs responsible for the common turf damage we see in Texas are beetle grubs. While there are more than 100 species of these beetles that call Texas home, only a few of those are responsible for turf damage.
Most beetles generally take about a year to grow from egg to adult beetle. Late spring is when adult beetles emerge and mate, with momma beetles laying between 30-40 fertilized eggs shortly thereafter. In about two weeks, the tiny white grubs hatch and feed for about a year before moving into a pupa stage, which is the last growth stage before becoming an adult. Grubs are easy to identify: Small, white, and c-shaped with three pairs of legs.
While these baby grubs eat and grow that first year, they become dormant once the weather turns cool. During this stage, they eat very little or nothing at all. Though there is a window of overlap as growth cycles overlap, it’s the later-stage, larger larvae that do the most damage when the weather warms the following spring. At this point, the grubs can be anywhere between a half-inch and an inch long, making them easy to see if you turn the soil over. Essentially, these larvae are teenagers and have the appetites of human teenagers, which is why they can do so much damage to your lawn.
May/June Bug Larvae
Right now, many lawns are playing unwanted host to the white grub, which is the larval scarab beetle, more commonly known as May/June beetles or chafers. Not all beetles are bad, and in fact, only a few beetles cause turf damage.
These particular larvae are active now, and their preferred diet includes the roots and underground portions of common warm-season (and even some cool-season) turfgrasses. This damage typically includes irregularly shaped areas of dead turfgrass that almost resembles drought damage. You may also find secondary damage from outdoor scavengers, such as raccoons and armadillos, who actively seek out these grubs as a source of food.
To Treat or Not to Treat
Depending on the infestation, no treatment may be necessary. The common threshold where treatment becomes necessary is 5 to 10 grubs per square foot, but this involves digging, which could damage your turf. Some areas are also more prone to infestation, which can be a big tip-off if this happens every year in the same spot.
Grub-damaged turf is easy to pull up because it often lacks roots and is typically yellow or dying.
If the grubs are picnicking in a high-value area of your turf, that can also influence whether or not treatment should happen. An area smack-dab in the middle of your lawn (or in a prime fairway area on a golf course) is probably a stronger candidate for treatment than a patch behind your garage that nobody can see.
How to Treat Larvae
Advances in insecticides have created long-lasting grub treatments. Typically, we recommend waiting until after the beetles stop mating to ensure that the insecticide doesn’t break down too early. There are a variety of effective products on the market, including some formulas that include preventative treatments as well as insecticides to take care of the current infestation.
Late-season treatments are also available. If you’re concerned about the effects of insecticides, a natural option is to introduce nematodes (also known as roundworms) into the area. However, this tends to be a more expensive and less reliable option than the proven insecticidal approaches.
Irrigation is also an important part of a successful grub treatment. Pre-watering encourages grubs to come to the surface, making them easier targets for the application. Watering after treatment also helps filter the insecticide further into the ground.
If we suspect grubs are noshing away on your lawn, we’ll bring it to your attention and review the appropriate treatment options. If we’re not currently providing seasonal service to you and you think you might have some issues, give us a call! Our treatments are effective – we can take care of this problem so your lawn can be healthy and beautiful for the summer.