How to beat Japanese beetles and emerald ash borers this year

How to beat Japanese beetles and emerald ash borers this year
Emerald ash borers

If you act now, this could be the year you get out ahead of Japanese beetles and emerald ash borers.

The two garden pests frustrated homeowners and clogged gardening hotlines last summer. Experts say now is the time of year to attack if you hope to win the fight preemptively.

Here’s a quick plan of attack, with help from Jonathan Larson, a Ph.D. entomologist with the University of Nebraska-Lincoln Extension, and supplementary information from the Nebraska Department of Agriculture.

Japanese beetles

Protecting trees before beetles emerge

» Buy a soil drench of a systemic insecticide, such as Fertilome Tree & Shrub, Bayer Tree & Shrub or Ortho Tree & Shrub (look for one that contains imidacloprid or dinotefuran).

» Apply it before Mother’s Day.

» Do not apply these drenches to linden trees. Instead, consult an arborist for other options.

Protecting trees after beetles emerge

» For an organic approach, apply Neem or Pyola to leaves every week to ward off beetles.

» Knock adult beetles into a bucket of soapy water to kill them one-by-one.

» Hire an arborist to apply pyrethroid insecticides or Acelepryn to protect leaves.

Protecting your lawn before grubbing

» Buy a grub prevention treatment like Scott’s GrubEx or Merit (look for chlorantraniliprole or imidacloprid).

» Apply it in June, no later than the Fourth of July.

» If you have a lawn care service, most will apply this for you.

Emerald ash borers

Assess your tree

» Call an arborist to inspect your ash trees.

» Determine, with the arborist, whether the ash is healthy enough to be treated successfully.

Managing unhealthy trees

» If your tree isn’t healthy enough for treatment, removing the tree before the borer kills it will save you money in the long run.

» Do not transport firewood. Burn it at your location to prevent the borer from spreading.

Treating healthy trees

» For ashes less than 20 inches in diameter at chest height, treat with soil drench products such as Fertilome Tree & Shrub, Bayer Tree & Shrub or Ortho Tree & Shrub (look for products containing imidacloprid or dinotefuron). Apply between now and Mother’s Day.

» For ashes greater than 20 inches in diameter at chest height, hire a professional arborist to treat the tree with a soil or trunk injection or a bark spray.

» Keep in mind, some treatments may need to be applied every year for the duration of the tree’s life. Others, such as emamectin benzoate, can be applied every other year.

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