Go Back  DoItYourself.com Community Forums > Garden and Outdoor Center > Gardening and Horticulture
Reload this Page >

white stuff on my hemlocks; disease or insects?

white stuff on my hemlocks; disease or insects?


Old 04-30-08, 09:21 AM
eddieo45's Avatar
Thread Starter
Join Date: Feb 2005
Location: Milton, MA
Posts: 278
white stuff on my hemlocks; disease or insects?

There's a white powdery kind of stuff on some of my hemlocks (and I've seen it on some around the block as well); a nearby landscaper says it's a disease, and must be treated, but a tree person took a look and said it's an insect. He proposed two applications of an oil, at a total cost of $270. Any thoughts?
Sponsored Links
Old 04-30-08, 10:39 AM
Join Date: Aug 2000
Location: USA
Posts: 15,834
Woolly Hemlock Adelgid crawlers love hemlocks. These crawling suckers' eggs form a powdery mildew at base of needles. They can stunt growth, discolor needles and eventually cause limb loss, usually beginning in topmost branches.

Horticultural oil will smother insects. Care should be ongoing. Height of tree usually makes it impossible for the average homeowner to properly care for hemlocks. Dense foliage usually can't be properly pentrated with water hose applications by the DIYer.

Spider mites is also a hemlock pest. You can shake a branch over a piece of white paper to see if you shake off black specks that when crushed produce a reddish streak.

Hemlock Wooly Adelgids
Photo Credit: Ontario Trees and Shrubs

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes