2-month-old hemlock seedling
2" tall

1-year-old hemlock sapling
12" tall

3-year-old balled & burlapped hemlock sapling 4' tall

8-year-old hemlock
15' tall

30-year-old hemlock
60' tall

Hemlock root flare

Hemlock trunk / bark

Hemlock canopy

Hemlock branch with new
green growth in spring

Hemlock cones in summer

Hemlock cones & seeds in fall

Normal needle shedding
in spring & fall

Lightly infested branch

Moderately infested branch

Heavily infested branch

Heavily infested branch
in decline

Lightly infested tree:
few egg sacs on less than half of tree, dense foliage, bright green new growth in most recent spring

Moderately infested tree:
more egg sacs covering ½ tree,
foliage not as thick as normal, little new growth in most recent spring

Heavily infested tree:
many egg sacs covering most of tree, thinning grayish green foliage,
no new growth in most recent spring

Heavily infested tree in decline: 
fewer egg sacs, serious
defoliation, gray-green color,
limb die-back, no new growth

Cluster of HWA eggs laid in
early spring & early summer

HWA egg sacs most visible in
spring and early summer

HWA crawlers emerging from egg sacs
in spring and early summer

HWA crawlers compared to a penny

HWA nymphs exposed on branch
in summer dormancy

HWA adult in late winter & early summer
laying new generation of eggs

Soil injection

Soil drench

Foliar spray

Trunk spray

1.  Mix treatment product according to
soil moisture level

2.  Pour mixture into injector tank

3.  Measure trunk diameter at breast
height (circumference divided by pi 3.14)

4.  Inject treatment material into soil around
base of tree (1 hole per diameter inch)

5.  Mark each tree
as it is treated

6.  Give tree extra water
if soil moisture is very low 

Sasajiscymnus tsugae

Scymnus sinuanodulus

Scymnus ningshanensis

Scymnus coniferarum

Laricobius nigrinus
feeding on adelgid egg sacs

Oviposition jars in which
beetle eggs are laid

Tents in which beetle eggs
are reared to adults

Scientist inspecting and
counting beetle eggs and adults

Clip dish used for releasing beetles
into the forest

Fabrella needle blight
caused by Fabrella tsugae

Hemlock rust caused by
Melampsora abietis-canadensis, Pucciniastruin myrtilli,
or Pucciniastrum hydrangeae

Rosalinia needle blight caused by
Hypoxylon herpotrichoides
(formerly known as
Rosellinia herpotrichoides)

Tip / shoot blight caused by
Sirococcus tsugae

Bag worms

Elongate hemlock scale

Hemlock borer gallery

Hemlock looper

Hemlock rust mite damage

Indian wax scale