Grub Damage in a Lawn
by Alec McClennan, on
A Grub Damaged Lawn - Does your lawn look like?
It's kind of a bummer when you wake up one day and your lawn is turning brown. To add insult to injury the local skunks and racoons take up residence in your lawn. What's going on here? It's classic White Grub Damage. You'll notice White Grub damage in Late September and October and it's particularly bad during years when we get a lot of rainfall in July and/or August (or if you water your lawn). Summer rains attract grubs to your lawn and then keep their eggs hydrated (alive) long enough for them to turn into baby grubs. Baby grubs are really hungry and can quickly devestate a lawn (like the lawn pictured above).
How to Prevent Grub Damage Without Chemicals
So you don't want your lawn destroyed by grubs, but you don't want to use a chemical to kill them? There are a lot of good reasons to avoid using the standard grub control chemicals which are linked to many bird deaths and honeybee colony collapse disorder. In addition, the grub chemicals are typically applied in the spring and sit on the lawn all season long waiting for tiny grubs to show up in the fall. Who wants your kids or dogs to be playing on a blanket of insecticide? Not me. Here's the good news, there is a totally non toxic way to prevent grubs from tearing up your lawn, and it's really easy.
Nematodes are microscopic soil organisms, as with people, there are good nematodes and bad nematodes. The good nematodes are called "beneficial nematodes". Nematodes happen to enjoy making their home on grubs and eventually killing them. The more good guy nematodes you have in your soil, the fewer issues with white grubs, fleas, and ticks you'll have because the nematodes kill them. How do you get nematodes in your soil you ask? It's easy, you can buy dormant nematodes and apply them with a hose end sprayer.
How to Apply Beneficial Nematodes
It's important to apply nematodes for grub control when the sun is not out because exposure to too much sunlight will kill them. In our lawncare business we try to apply them during days where there is a good chance for rain. If it's cloudy and rainy, the nematodes will have a chance to get down into the soil before the sunlight gets them. Think of Nematodes as microscopic vampires who feed only on white grub and other larvae in the soil. If you're applying them yourself, I would recommend either putting on your raincoat and applying them in the rain, or applying them in the evening as the sun is setting, then setting up a sprinkler to water them into the soil.
A Hose End Sprayer (Ortho Dial a Mix) is a great way to apply nematodes. Just dump in the powder add water, shake well and spray away. Make sure the nematodes are well dissolved before trying to spray or they may clog up your hose end sprayer. Also, I'd use about 50 million nematodes (enough to treat 5,000 square feet) per hose end sprayer. If you don't know the size of your lawn, try measuring it on www.findlotsize.com. Set the sprayer for 2 ounces per gallon, and spray 5,000 s.f. multiple times until you're out of nematodes.
When to apply Beneficial Nematodes
The best time of year to apply Nematodes to control White Grubs is in the Late Summer or Early Fall. If you water your lawn regularly I'd recommend applying nematodes in late august. If you don't water regularly, anytime in September should be ok, but probably the earlier the better.
How to Fix Grub Damage in a Lawn
Sometimes, skunks and racoons will flip up chunks of sod looking for grubs. If you catch this in time and lay the sod back down then water it deeply, many times the lawn will recover. You can apply an organic animal repellent like Nature's Defense or call in an animal trapper to start reducing your critter population. I prefer to use the repellent because in my neighborhood we could be trapping for a long time before we successfully relocated enough skunks and racoons to make a difference.
If the lawn is just brown and dead looking, you'll probably need to reseed. The key to successful seeding is seed to soil contact. One labor intensive way to achieve this is to physically remove all the dead grass and haul it to your compost pile, then scrape up the soil with a garden weasel, seed, and mulch with straw (1 bale per 1000 s.f.).
Another way might be to order some topsoil and just cover the entire dead area with a very thin layer of soil (1/2 inch or so). 1 Yard of soil should cover about 500 square feet with a light layer of soil. You cover the dead areas with dirt, seed, and mulch with straw. We recommend seeding with Good Nature Tuff Turf which is a premium blend of Turf Type Tall Fescues (95%) and Kentucky Bluegrass (5%). Turf Type Tall Fescue has a deep root system and seems to be less likely to get damaged by grubs or animal digging. I wouldn't call it grub proof, but it's a lot more resistant to grubs than shallow rooted grasses like bentgrass are.
If you have a large flat area of grub damage, it might make sense to rent a little machine specifically designed for fixing up lawns. It's a Toro Dingo with a soil cultivator attachment. The soil cultivator will turn dead grass into a ready to seed into seed bed. It takes a little getting used to and isn't effective if there are a lot of tree roots, but if you have an open dead area, it works great. Check out our Lawn Renovation Page for videos of the Soil Cultivator and Dingo in action.
Milky Spore for Organic Grub Control
Milky Spore is another natural alternative for controlling grubs. I'm not a huge fan of milky spore for grub control because it only controls Japanese Beetle Grubs and there are a whole host of other grub species that damage you're lawn. Milky Spore is a good tool if you're trying to reduce the levels of Japanese Beetles in your yard, but not the best product if you're trying to control grubs in your lawn.
Neem Oil for Grub Control
Oil from the Neem Tree in India works minor miracles on plants. It coats leaf surfaces and protects them from disease (great for roses) and it acts as a repellent / anti - feedant for insects that like to feed on plants. If you apply Neem Oil to your lawn three times a season (June, July, and August) the likelihood that you'll have grub damage is reduced. It may also protect the lawn from disease issues.