Japanese Beetles by Upper Wilket Creek: August 2021

There is a trail which follows Wilket Creek south starting at York Mills just east of Bayview.

Mallards

MYSTERY PLANT

I will identify it at the end of the post.

Something has been eating many leaves here and closer inspection led me to a group of Japanese Beetles.

Japanese Beetle
Japanese Beetles

I add some notes from the Ontario Ministry of Agriculture website.

Adults

  • Shiny metallic green body with copper coloured wings
  • Small white tufts on the sides and tip of their abdomen 
Japanese Beetles
Japanese Beetle

Injury

  • feed on the upper surface of young succulent foliage
  • chew the tissue between the veins and creating a lacy appearance
Japanese Beetles
Japanese Beetles

Scouting Notes
Adults emerge around the time that Canada thistle, chicory and Queen Anne’s lace bloom. Damage to wild grape is a good indicator of beetle feeding. It has been noted that after emergence, adults will feed on shorter plants first, for example weeds, and then move to taller plants later in the season. Beetles will drop from foliage if disturbed.

Japanese Beetles

Threshold
There are no established thresholds for this pest. Vines can tolerate some leaf area loss without impacts to growth. Tolerance for feeding damage on leaves depends on the health of the vine (growth stage, crop level, weather stresses) and the presence of other foliar pests. In years of vigourous growth, vines will tolerate more feeding. 

Some botany:

Bull Thistle (Cirsium vulgare)
Evening Primrose (Oenothera)
Enchanter’s-nightshade ( Circaea canadensis)
Nipplewort (Lapsana communis)
Alternate-leaved Dogwood (Cornus alternifolia)
Giant Ragweed (Ambrosia trifida)
Basswood (Tilia americana)
Gray Dogwood (Cornus foemina)
White Cedar (Thuja occidentalis)
Hedge Bindweed (Calystegia sepium)
Heal-all (Prunella vulgaris)
Canada Thistle (Cirsium pratense)
Mullein (Verbascum thapsis)
Enchanter’s-nightshade ( Circaea canadensis)
Bittersweet Nightshade (Solanum dulcmara)
Bittersweet Nightshade (Solanum dulcmara)

MYSTERY PLANT

Not every year is a good year for this large nut-bearing tree but this year is. Black Walnut.

Black Walnut (Juglans nigra)

NATURE POETRY

I am set to light the ground,
While the beetle goes his round:
Follow now the beetles hum,
Little wanderer hie thee home. – William Blake (1757 – 1827)

Miles Hearn

1 thought on “Japanese Beetles by Upper Wilket Creek: August 2021

  1. Lisa Volkov

    I sure know the Black Walnut–that’s one I learned to remember, all right–with help and encouragement on your walks!
    The Japanese Beatle may be voracious and damaging in its eating practices, but it does deserve to be featured in its own right, and it isn’t bad to look at, either.
    And beautiful botany, in another place I love. Thanks, Miles!

    Reply

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