Plant Tolerance of Japanese Beetles

E = evergreen; N = native to Maine

Trees Not Preferred by Japanese Beetles:
Abies species E, some N Fir
Acer rubrum N Red Maple
Acer saccharinum N Silver Maple
Fraxinus americana N White Ash
Fraxinus pennsylvanica N Green Ash
Liriodendron tulipifera Tuliptree
Magnolia species Magnolia
Pinus species E, some N Pine
Quercus rubra N Red Oak
Thuja occidentalis E, N Arborvitae; White Cedar
Tsuga canadensis E, N Canada Hemlock
Shrubs Not Preferred by Japanese Beetles:
Forsythia species Forsythia
Hydrangea species Hydrangea
Juniperus species E, some N Juniper
Ilex species some E, some N Holly
Symphoricarpos orbiculatus Coralberry
Syringa species Lilac
Taxus E, some N Yew
Perennials Not Preferred by Japanese Beetles:
Aquilegia species some N Columbine
Coreopsis species Tickseed
Dianthus species E Pinks
Digitalis species Foxglove
Heuchera species Coralbells
Lilium species some N Lily
Papaver species Poppy
Veronica species Veronica
Viola species some N Viola, Violet
Annuals Not Preferred by Japanese Beetles:
Ageratum houstonianum Ageratum
Antirrhinum majus Snapdragon
Begonia species Begonia
Celosia species Cockscomb
Lathyrus odoratus Sweetpea
Tropaeolum majus Nasturtium
Plants Very Frequently Attacked by Japanese Beetles:
Acer palmatum Japanese Maple
Aesculus hippocastanum Horsechestnut
Alcea rosea Hollyhock
Betula populifolia N Gray Birch
Malus cultivars Crabapple; Apple
Prunus species some N Cherry, Plum
Tilia americana N Basswood
Preferred Hosts of Japanese Beetles:
Betula species some N Birch
Fragaria hybrids Strawberry
Malus cultivars Crabapple
Vitis species some N Grape

White Grubs in Maine Lawns

Six species of white grubs occur in Maine. They are the ground-dwelling larvae of these insects:

  • Japanese beetle
  • European chafer
  • Oriental beetle
  • May beetle (also called June beetle)
  • Asiatic garden beetle
  • Rose chafer

To scout for white grubs, which feed on plant roots:

Use a shovel to cut three sides of a 12” square in a lawn. Grab the open edges and peel back the square of turf like a carpet. Look for C-shaped white grubs on the newly exposed soil. Sample several places.

When to do something about white grubs:

If there are fewer than 5 grubs per square foot: don’t treat.

If there are 6-9 grubs per square foot: An otherwise healthy lawn can tolerate this level of grubs. However, if skunks, raccoons, birds and moles are digging to find the grubs, you may wish to treat areas with high numbers of grubs.

If there are more than 10 grubs per square foot: you may wish to treat.

Treatment products and timing vary, depending on type of grub. Call your UMaine Extension county office for advice.

From the GardenPro Answer Book; revised and updated by Lois Berg Stack, Ornamental Horticulture Specialist, University of Maine Cooperative Extension.