While a relatively small percentage of Delaware lawns will actually get grubs in a given year, this insect can wreak havoc when a significant population occurs on a lawn or other turf area.
Unlike the common earthworm, grubs, or the larval form of various insects, are terrible for your lawn. They are most prevalent in summer, when insects are plentiful and the moist grass of well-tended lawns provides an attractive site for them to lay their eggs. The first step in prevention is learning to recognize grub problems before they have the chance to make your lawn a mess.
Since grubs are often asked about, this Lawn FAQ features grubs in lawns and summarizes the most common questions regarding this destroyer of home lawns.
How do I know if I have grubs in my lawn?
Peeling back a damaged lawn area has revealed these grubs in the soil as the cause.
Check for browning.
Grubs feed on the roots of grasses, so lawns will show wilting and browning of irregular shaped areas. Certainly there could be many reasons for lawns browning, especially in late summer when most grub damage occurs. Always check the root zone of affected areas for the c-shaped grubs. Carefully pull back the sod in suspect areas, in particular the marginal areas where brown grass meets green grass, and look for the grubs. Usually a population of about 10 or more grubs per square foot will lead to browning of the lawn.
Keep in mind other factors that can lead to poor rooting and are mistaken for grubs. For example, lawns in shade areas often have weak roots and are pulled-up easily. Grubs do not typically appear in shade lawns. Also, many lawns were easily pulled up this spring and grubs were blamed. Once grass dies, regardless of the cause, roots will rot away and the grass is very easy to tear out. So trying to diagnose grub damage from the previous season as the cause of a dead lawn area in spring is very difficult to do, even if limited roots are found in an area of dead grass.
Another sign of grubs is damage from skunks and raccoons digging up lawns in search of grubs to eat. This usually happens at night. Moles may or may not be feeding on grubs so are not a reliable indicator of grub problems.
Test the Strength of the Grass
Grubs’ favorite food is grass roots. If the roots of your grass have recently been munched away, the grass may still look green (temporarily), but come out too easily when pulled.
Why does my lawn have grubs but not my neighbor?
Keep in mind the adult stage of the grub life cycle is a beetle, which can fly. Random chance is part of the answer. But adult beetles usually lay eggs in full-sun lawn areas with adequate soil moisture. The masked chafer (annual white grub) and Japanese beetle lay eggs in July. So if the weather has been dry but your lawn is watered and surrounded by dry lawns, it is a prime target for egg laying.
How can I predict if my lawn will have grub damage this year?
The masked chafer is the adult beetle which lays eggs becoming the annual white grub in lawns.
Japanese beetles fly during the day and feed heavily on many ornamentals. Noting these adults and then having irrigated lawns surrounded by drier turf increases the chances of grub damage to your lawn. Watch lawns closely starting about mid-August and continuing into September for wilting and browning areas, and then check the root zone for grubs.
If you still uncertain if you have grubs give us a call. We can certainly help
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