Hemlock Wooly Adelgid

The Hemlock Wooly Aldelgid (HWA)

• • This is a small, invasive insect that poses a serious threat to hemlock trees.

  • They feed on the sap of hemlock trees, which weakens and eventually kills them.

  • They are easily identifiable by the white, cottony masses they produce, which look like tiny woolly balls, particularly on the underside of hemlock branches.

  • It is an invasive species that has caused widespread hemlock tree death in eastern North America.

  • It is important to be "diligent" in watching for this pest, and in not transporting firewood, to prevent its spread.

Essentially, the "woolly" part of the name refers to the white, wool-like egg sacs the insect produces, and the "adelgid" part is the type of insect it is.

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Instructions for applying the systemic insecticide Imidaclopred 2F 

The product used is Mineiro 2F Flex Imidacloprid Systemic Insecticide (1 Gal) by Atticus. It is available on Amazon for $66 per gallon (in 2025).  Make sure you order exactly what is listed here.  Other formulations of Imidacloprid do not apply to this application.  This product is a super concentrate, and you will dilute it twice during the application.  It comes in gallons, but you can only use about 28 ounces per year per acre. This amount of solution would cover about 17 15-inch diameter trees.