Stem Rusts

Question 1

What are some general life cycle characteristics of rust basidiospores?

Answer 1

• Basidiospores (1n) generally thin walled and have a short range.
• infects primary host via stomata or new epidermis
• intercellular mycelia between host cells emit haustoria which penetrate cell wall but not membrane.

Question 2

What are some char’s of spermatia?

Answer 2

• sweet clear ooze containing
• non infective spores
• fertilization (start of sex) creates dikarya (containing 2 seperate nuclei) which are then carried by insects

Question 3

What are the characteristics of aeciospores ?

Answer 3

• often blister like structures beneath skin
• thick walled (100 km or more range)
• Infect secondary host (intercellular mycelia and haustoria)

Question 4

What are the alternating hosts?

Answer 4

Pine and ribes

Question 5

What are some characteristics of urediniospores

Answer 5

• orange pustules on leaf
• quick cycling time (weeks) add up to many cycles over a summer.
• increases infection on secondary host.

Question 6

What are the characteristics of teliospores?

Answer 6

• 2 1n nuclei fuse (2n)
• may overwinter
• produce 4 basidiospores (1n)

Question 7

What are the native stem rusts?

Answer 7

• Endocronartium

- cronartium (Pl and other pine)

Question 8

What are stem rusts?

Answer 8

• A class of basidiomycetes
• obligate parasites (protected environment and nutrients)
• sneak entry through stomata results in lowered defense response by tree
• Thrive best on vigorous host.
• Secondary organisms cause tissue death
• require alternate hosts
• up to 5 spore stages