DRB

Question 1

How does black stain infect and spread?

Answer 1

bark beetles carry the disease and infect upon first contact. The disease can then spread by root contact.

Question 2

What is the rate of spread of DRB?

Answer 2

• 1-2m along the roots since it travels along vascular pathways. Very fast (not slowing down to decay wood)
• long distance introduction by beetles.

Question 3

What type of fungi is DRB?

Answer 3

An ascomycete. obligate parasite, does not persist long in stumps after JS.

Question 4

What are some factors that increase a trees likelihood of beetle attack and DRB infection?

Answer 4

• Attracted to newly injured trees
• Stumps at JS are vulnerable
• Can build up in JS slash

Question 5

-What is the meaning of complex?

Answer 5

more than one agent attacking tree

Question 6

How does DRB damage trees?

Answer 6

Mortality - Blocks vascular system and generates toxins

Question 7

What are some aspects of FD damage by DRB?

Answer 7

• window of death 15-60 years
• mortality declines after 25+ years
• centers of 30 trees have been recorded

Question 8

What are some aspects of PL damage of DRB?

Answer 8

• window of death is trees over 50
• more likely at 80-1000m elevation
• as big as 50% mortality in large areas

Question 9

What are the signs and symptoms of DRB?

Answer 9

• Black/purple streaks in sapwood

- Beetle/weevil activity at root collar

Question 10

What are the hosts and range of black stain?

Answer 10

Fd variety - range of Fd

P variety - s.interior