Entomology: Hemlock Woolly Adelgid
Problem:
The hemlock woolly adelgid feeds on the sap of hemlock trees which causes death of the branches and, eventually, of the tree.
Order: Hemiptera. Family: Adelgidae. Common Name: Hemlock Woolly Adelgid.
Mouthpart of HWA.
2.00MB MPG © Rutgers University; lashomb. (29.May.2006)
Larvae:
The larvae are mobile and, once hatched, they move to areas of new growth where they feed on the tree's sap.
(Egg cluster | enlarge)
Order: Hemiptera. Family: Adelgidae. Common Name: Hemlock Woolly Adelgid.
Mobile larvae of HWA.
974KB MPG © Rutgers University; lashomb. (29.May.2006)
Eventually, they lose the ability to move.
Nymphs:
The sedentary nymphs secrete the white cottony material that marks the presence of the hemlock woolly adelgid on a scale observable by the unaided eye.
Order: Hemiptera. Family: Adelgidae. Common Name: Hemlock Woolly Adelgid.
Close-up of HWA on hemlock branches.
1.89MB MPG © Rutgers University; lashomb. (29.May.2006)
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Management:
The beetle, Pseudoscymnus tsugae, seen in the video is a natural predator of the hemlock woolly adelgid in their native Asian countries.
Hemlock woolly adelgid: eaten by beetle.
510KB MPG. © Rutgers University; jzaaa. (03.Oct.2005)
The benefit of P. tsugae is that the beetle's primary prey is the hemlock woolly adelgid. The specificity of the beetle's feeding habit decreases the risk of it damaging other native insects.
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Further Information:
http://www.rce.rutgers.edu/pubs/publication.asp?pid=FS751
http://www.state.nj.us/agriculture//plant/ptsugae2002.pdf