GruesomeGrubsTackle nasty lawn grubs NOW—Before
grow up into Japanese beetles and other pests!
Q. Dear Mike - I am turning the
front yard into a garden (perennials and shrubs) - no more lawn mowing!
In the process of trying to break through the clay I found lots of
grubs. This probably explains why I had so many Japanese beetles last
summer! My organic options seems to be nematodes, which look like they
need to be applied each year, and a ‘milky spore’ that is said to last
ten years or more. What do you recommend?
---Ellen, Esq. In
Hi, Mike. We moved into a new home, and have grubs by the ton!
Literally every shovel full of dirt I turned over while putting in new
flower beds last Fall unearthed at least a half dozen. I'll probably be
most inclined to take action if you tell me that they'll also devour
the roots of the flowers we're planting. Thank you, and keep up the
---Vince in Coopersburg, PA
My lawn needs desperate help. My main problem is grubs - Japanese
beetle and Masked chafer are both present, and I have brown patches in
---Linda; New Stanton, Pennsylvania
A. “Desperate help”? Is that
like “Desperate housewives”? Or just a reference to what kind of
assistance you expect here? Let’s see how desperate we can get…
White grubs—ugly grayish-white crescent shaped creatures—are the larval
forms of a number of beetles. The best known is the Japanese beetle,
but grubs can also be baby beetles of the May, June, Asiatic garden, or
Oriental variety; or Northern, Southern or European masked chafers. (http://ohioline.osu.edu/hyg-fact/2000/2505.html)
If you’re game, you can identify your exact grubs by their distinctive
hinders. Yes, only You Bet Your Garden could bring you a University
paper that will soon have you scrutinizing your nasty grubs’ rear
ends—you just don’t get this kind of service from other gardening
shows! Here’s the link to Ohio State University’s ‘beetle-to-be hinder
Have fun, kids!
The adults all have the same basic body type—the classic ‘scarab
beetle’—and pretty much follow the same life cycle. Adults emerge in
early summer, copulate as they defoliate (most of ‘em, that is—some
adult beetles don’t bother plants at all!) and then the females lay
eggs mid to late summer. Japanese beetle females only lay their eggs in
sod—so if those are the only grubs you have, your flower roots will be
safe. But others, like May and June beetles, lay their eggs in plain
old dirt, and their grubs will eat the roots of flowers and veggies.
Anyway, the eggs hatch quickly, the grubs feed on roots (grass for
most, but ornamental plants for some), go through three fast molts and
are about an inch long and eating a ton by Fall. When the weather
chills, they drop below the frost line, moving back up when the soil
warms in Spring.
Large numbers of grubs feeding in a lawn will cause brown patches that
look like drought stress to appear in late summer. To make sure that
grubs are the cause, lift up these dead areas when the pests are close
to the surface—in general, August and September in the Fall, and April
and May in the Spring (as soon as soil temps reach 60 degrees). Got
grubs? You have two good options to knock them out before beetles fly
“The Spikes of Death” is the nickname a researcher gave those
lawn-aerating sandals you see in garden catalogs (just search the term
“lawn aerating sandals” on the web). Now, these things don’t aerate
lawns—you need to pull up plugs of earth to do that; but they are the
perfect length to spear grubs when the pests are close to the surface.
Just walk overtop of your brown patches this Spring when a soil
thermometer says the dirt is 60 degrees and you’ll kill more grubs than
an insecticide. Same thing in the Fall. Be sure and think good thoughts
as you dance.
Beneficial nematodes are microscopic wormy little guys that come packed
five to 50 million in little sponges. You water them into a wet lawn on
a warm evening and they work their way down below the soil line to prey
on grubs. The members of a newer strain (Heterorhabditis species as
opposed to the older Steinernema types; pay attention—there’s going to
be a test after the show) are more aggressive and mobile, actually
going after the grubs as opposed to lurking in wait for them. When you
buy nematodes make sure their scientific name starts with an ‘H’, and
not an ‘S’. (Gardens Alive “grub away” nematodes are the right species,
and they offer two kinds—one for Southern
lawns, and a ‘Northern’
variety that is active in cooler soils.)
Yes, you do need to reapply the nematodes every year (the same is true
with toxic insecticides, which you won’t even consider using because
you’re too smart to poison yourself, right?). You can release them in
Spring or Fall. Or both if you need to control a really severe grub
problem. They won’t harm good soil dwellers, like earthworms, but are
effective against some other lawn pests, AND they kill flea larvae in
your lawn, which makes Springtime release a really, really good idea if
fleas have troubled you in the past. They are very cool little guys.
Milky spore disease is one of the oldest organic remedies. (Here’s a
great scientific article about it: http://www.ag.uiuc.edu/cespubs/hyg/html/200120b.html;
you can find it for sale at most large garden centers.) Apply it to a
lawn as directed once every summer three years in a row and it will
build up enough disease spores in your turf to prevent grubs for a
decade or two. But it doesn’t have much effect the first couple of
years, and it only works on Japanese beetle grubs. So check them
One of the most effective controls is to simply avoid watering your
lawn in the late summer egg-laying season; the eggs will die if the
turf is dry. Don’t chase starlings; these so-called ‘pest’ birds feed
on the grub-babies in your lawn and adult beetles! Another great
natural enemy is the Spring Tiphia wasp; the female goes down into the
soil and lays her eggs right on the pests, killing up to 85 percent of
the grubs in a lawn—better than nasty chemical insecticides! Plant
and firethorn to attract these great
beetle-killers; and don’t kill what looks like winged carpenter ants
visiting those plants in the Spring; those are the wasps!
And finally, don’t plant the adult beetle’s favorite foods near lawns
if you can help it. With Japanese beetles, that means keeping the roses
away, of course. With other types, it’s fruit
trees and shrubs.
them grub hinders and then go look up what Mom and Dad like to eat.
Products From Gardens Alive!
Get nasty Grubs out of your soil and improve your Garden with these
Grub-Away®Nematodes North Pkg of 5 million
These nematodes activate in soil temperatures of 50-80°F
Controls borers, Japanese beetle grubs, masked chafer grubs, and more!
Grub-Away® Nematodes South Pkg of 5 million
Activated in soil temperatures of 70°F and remaining active to
Controls fire ants; fungus gnats; masked chafer grubs, other white
grubs and more!
Tiny parasite attacks eggs of more than 200 types of insect pests
Trichogramma larvae eat pest insect eggs--before they can develop into
destructive pest adults. Provide protection all season.