1. Ribes spp. are
infected with WPBR
spores during spring.
infected with WPBR
spores during spring.
2. The Ribes spp. grow in
ideal conditions throughout
the summer
ideal conditions throughout
the summer
3. The WPBR develops on
the underside of the leaves.
You can see this on
currants and gooseberries
the underside of the leaves.
You can see this on
currants and gooseberries
4. In the fall the telia hairs
are well formed and ready
to infect pines.
are well formed and ready
to infect pines.
5. The infected Ribes spp.
leaves are arranged on
metal screens.
leaves are arranged on
metal screens.
6. The screens are placed
in racks above the
seedlings being screened
for resistance. Samples
are taken to ensure the
seedlings are well
inoculated.
in racks above the
seedlings being screened
for resistance. Samples
are taken to ensure the
seedlings are well
inoculated.
7. The inoculated seedlings
develop indications of
infection on their needles.
develop indications of
infection on their needles.
8. The seedling on the left
is susceptible and will die.
The seedlings on the right
are resistant and indicate a
resistant parent tree.
is susceptible and will die.
The seedlings on the right
are resistant and indicate a
resistant parent tree.
Genetic testing at the Forest Service's Sugar Pine Blister Rust Program
