EHS (Fiorinia externa)
PDF version of EHS - Facts at a Glance (with photos)
Where from: Japan
Host plants: Hemlocks, firs, Douglas fir, blue spruce, Atlas cedar, occasionally other conifers
Symptoms: Occasional mottling on foliage; white from male scales
Important cultural practices:- Don't interplant
- Remove large hemlocks or treat them for scale
- Cull heavily infested trees
- Don't overuse nitrogen fertilizers
- Limit use of broad spectrum insecticides
- Butt-prune trees for better coverage
Scouting: Look for mottling or white from males whenever in trees. Thoroughly scout any time of year by scanning underside of needles for scales. Males are white, females are brown.Control considerations:
- Control with pesticides difficult as crawlers hatch throughout the year
- Good coverage is essential - targeting underneath needles and back into canopy to wet several years of growth
Life cycle:
- How overwinters: All life stages
- Number of generations per year: Multiple overlapping non-synchronous generations - approximately 16 weeks to go from crawler to adult producing crawlers
Biological control: The parasitic wasp leaves hole in scale when it emerges. Small black lady beetles, lacewing larvae and dusty wing adults and larvae also feed on scales.
