Final review: chapter 9 Stem and Foliage Diseases

Question 1

General characteristics of canker diseases

Answer 1

often associated with an injury or stress
death to the phloem, annual or perennial perennials more damaging
loss of timber, breakage and decay
monocultures are at high risk
effective self thinning method in natural stands

Question 2

signs, symptoms, damage characteristics and hosts of Atropellis

Answer 2

(DSA) Atropellis canker
hosts: Pl, Py
Perennial
common in dense suppressed Pl stands
Elongated canker below live crown
resin and small black fruiting bodies (apotecea-also assoc. with teapot rot)
stain in wood under canker
similar to stalactiform blister rust on older Pl, but no squirrel feeding

Question 3

signs, symptoms, damage characteristics and hosts of Dermea and Phomopsis

Answer 3

Hosts:Fd-seedlings and saplings
annual
main stem girdled-top death
trees exposed to drought or frost
old phomopsis cankers that do not girdle the entire stem look like axe wounds
Dermea cankers have red bands around canker (helps distinguish from Phomopsis)
High mortality for both-Phomopsis limited to small clusters of trees or individuals
Dermea is more widespread

Question 4

General characteristics of rusts:

Answer 4

galls, cankers, and foliage diseases
alternate hosts(this sets them apart from most diseases)
secondary insects
animal feeding

Question 5

White Pine Blister Rust

signs, symptoms, hosts, alternate hosts, damage characteristics

Answer 5

Cronartium ribicola
Hosts: Pw and Ribes
Diamond shaped cankers, orange spores in the spring
dead/red/yellow tops

Question 6

Stalactiform Rust

signs, symptoms, hosts, alternate hosts, damage characteristics

Answer 6

hosts: Pl, Indian Paint Brush
primarily young Pl
common life cycles similar to DSB
Diamond shaped canker
squirrel feeding 
looks the same as atripellis
distinctive dead (spike) top on older trees, if live crown below canker area

Question 7

Comandra Rust

signs, symptoms, hosts, alternate hosts, damage characteristics

Answer 7

complex life cycles similar to DSB
primarily young Pl, just as likely to occur on Py
host: bastard toadflax
elongated diamond shaped canker
some squirrel feeding
distinctive dead spike top on older trees, if live crown below canker area

Question 8

Western Gall Rust

signs, symptoms, hosts, alternate hosts, damage characteristics

Answer 8

Endocronartium harknessii
hosts: Pl, Py
No alternate host
Deformation in lower bole
airborne spores transfer to stem on other trees, takes three years for canker to develop
spores come from fruiting bodies in spring
squirrel feeding causes additional flagging on pines

Question 9

Spruce Broom rust

signs, symptoms, hosts, alternate hosts, damage characteristics

Answer 9

fairly minor foliage disease
doesn’t cause a lot of damage
large (usually) round ball of densely packed foliage
higher up in the tree pressed against the main bole
light green to red needles, needles cast late in year
alternate host: arctostaphylos uva ursi

Question 10

life cycle of white pine blister rust

Answer 10

1. Windborne basidiospores (spore 1) infect needles through stomata (takes 1-2years)
2. Spermatia (spore2) develop at canker margin and cause white blisters on bark. Spermatia fertilize spermagonia (spore 3). Once canker forms the branch is weakened and breaks off, which allows for decay entry.
3. Aecia formed where spermagonia were the year before. Windborne aeciospores infect Ribes.
4. Urediniospores reinfect ribes.
5. Teliospores reinfect ribes.
6. Teliospores germinate to produce basidiospores.

Question 11

what happens mid summer with white pine blister rust?

Answer 11

orange postules exume liquid that contains spore #2

Question 12

name the four spores in white pine blister rust

Answer 12

1. Basidiospores
2. spermatia
3. spermagonia
4. aesiospores

Question 13

management strategies for white pine blister rust:

Answer 13

1. SITE SELECTION FOR PLANTATIONS:
   too often overlooked
   favorable: dry conditions, well drained sites, south facing slopes with rapid evaporation
   avoid: any conditions/locations that favor dew build up
   small valleys/small openings surrounded by mature stands
   avoid sites with dense veg where ribes typically forms large colonies
2. THINNING AND PRUNING:
   thin affected trees, ID orange fruiting bodies in May-June to determine infected trees
   2a. SYSTEMATIC PRUNING:
   Target all Pw in stand, cut all branches up to a certain pre determined height (2-3m)
   Fall pruning ideal. avoid cold snaps and dont prune while sap running
   2b. PATHOLOGICAL PRUNING:
   Cut off diseased branches only.
   Can do anytime
   (criteria: if DSB t plant Pw
3. HARVESTING PRACTICES: Together, these are not very effective. could think about , but strategies could back fire.
   fire: unknown how it affects DSB
   -can reduce seed banking
   disturbance can also increase ribes seed germination
   Winterlogging:
   reduce disturbance means reducing seed bed opportunities
   Low volume partial cut: maintain low light levels reduces seed germination
4. RESISTANT STOCK:
   slow growing, small cankers
   developmental disease resistance
   totally clean(steroid free)
5. BIOLOGICAL CONTROLS
6. FUNGICIDES
7. ERRADICATION OF ALTERNATE HOST: Not practical unless on a small scale (1ha)
   WORST IDEA EVER

Question 14

Why do you increase infection when you thin without pruning?

Answer 14

because as you reduce density, air flow increases and opportunity for spore transfer/circulation increases