Hungry birds and critters appreciate grub-infested lawns, and based on observation and anecdotal evidence, the dining’s fine around the Bangor area this spring.
From Hampden to Holden, from Orono to Orrington, many lawns contain torn-up patches the color of dead grass. Visibly evident by late March, these patches really stand out as the surrounding grass turns green.
“It’s beetles and what’s eating them,” said Mike Legasse, who owns the Brewer-based Green Thumb Lawn Service. He explained that “there are numbers of beetles that lay eggs in lawns. The result of those eggs hatching is a white grub” that feeds on grass roots.
Melting snow exposes lawns in late winter and early spring; crows, raccoons, skunks, and turkeys then tear up grub-infested sections to dine on protein-rich grubs. The damage resembles that caused by a miniature rototiller, which in effect a hungry skunk becomes when tearing apart a lawn.
According to Legasse, the three primary beetle species that damage lawns are the European chafer, the Japanese beetle, and the Oriental beetle. “All of them create grubs that eat turf grass roots,” he said, “and they only eat turf grass roots.”
An adult female beetle lays eggs in June or July, depending on the species, and after the eggs hatch, larvae emerge that start “immediately feeding on the roots, kind of like an underground lawnmower,” Legasse said. “This detaches the plant from the roots.
“If you don’t control them (grubs), they continue to feed until fall,” then “go into the ground to overwinter,” he said.
Although “the [beetles’] life cycles … are very similar … they’re not the same,” Legasse said. “The European chafer is the worst of the worst; it comes out 30 days earlier in the spring and it stays out 30 days later in the fall.
“The treatment threshold for each of these grubs is different,” he said. Traditional grub-control products are:
• Liquid Sevin (carbryl) “doesn’t do a very good job,” Legasse said. “It needs to be heavily watered” when applied, and even then provides “only 40-percent control, if you get that.”
• Merit, which Green Thumb Lawn Service has used for eight years. “We’ve found some failure, but it gives you about 80-percent control.”
A few years ago Dupont Professional Products introduced Acelepryn, an insecticide that according to corporate literature is the “first and only grub control product that based on acute toxicology testing was not required by the EPA to include a Signal Word on the label.” Acelepryn also has “low impact on non-target organisms including birds, honey bees, fish and mammals,” according to Dupont.
“It works on all white grub species in the 90-percentile kill ratio,” Legasse said.
“It’s the first commercial insecticide released, to my knowledge, that does not have a Signal Word on it to indicate its toxicity,” he said, echoing Dupont’s claim.
This year, Legasse’s crews will apply only Acelepryn to control white grubs. “We put it down now (in the spring) so it’s in the soil profile” when beetle eggs hatch in June or July, Legasse said. “The plant material picks up the product,” and root-eating grubs ingest Acelepryn.
The insecticide “denies the grub the ability to process calcium,” so the grub cannot “grow” a jaw or exoskeleton, Legasse said. “The grub never completes its life cycle. It dies, and it doesn’t reproduce.”
Aware that some homeowners personally attempt to control grub infestations, Legasse cautioned that “you want to make sure you read the label or hire a professional” to treat grubs.
“Use the right control for the right reason at the right time in the right amount for the labeled pest,” he said.