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Hemlock Looper Moth

The Hemlock Looper is native to our landscape and found across Canada in the east as Eastern Hemlock Looper and west as the Western hemlock Looper.

We have concentrated our information on the Eastern Hemlock Looker.

They are noted for their looping characteristic when moving and are also referred to as “Inch Worms”

The damage occurs from feeding larvae.

Life Cycle

They are slender with no bristles or hairs and vary in color from mottled grey, brown to yellowish green. Egg Hatch, weather, and location related is between late May and late June. The larvae will develop through four or five instars. The larvae then pupate out of the sunlight, typically in crevices in the bark between mid-July to the end of August. Adults emerge after 10 to 15 days and immediately begin to look for a mate.

As not identified as a strong flyer they will be concentrated in small, localized areas. The female will lay eggs in small groups on the branches, bark, and on the forest floor. These small greenish eggs will remain there until hatch the following spring.

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The larvae feed on Balsam Fir, Hemlock and occasionally on Spruce and Larch

Balsam Fir 

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The larvae feeds on the new needles on the host tree when the larvae is in the early instars. As the larvae matures it will not limit its feeding to new foliage but will feed on old existing foliage as well. Because the infestation is usually limited to small areas, the level of defoliation is usually high driven by a concentrated number of feeding larvae. Adding to the damage is the fact that the larvae are wasteful eaters and do not completely consume the foliage. They will cut the needle off and allow much of it to fall to the forest floor.

Although outbreaks last only three to four years they can in high numbers kill the host tree in one year.

Control Measures

Btk can be aerially sprayed during the larvae stage to control the Hemlock Looper. Quick and early intervention is critical to reduce the amount of damage and mortality.

A single application of either Foray 48B or Foray 76B a more concentrated formulation at the prescribed label rate should provide adequate larval control.

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For more information please visit the following websites

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