White Pine Blister Rust Research at the Institute of Forest Genetics

after MGRAnnette Delfino Mix, Detlev Vogler

Screening for MGR

MGR Screening R-5 Placerville Nursery

•Screening process       

developed

• Transferred to R‐5 

Nursery 1986

Plug and Play Species

•Western white Pine•South western white      

pine

Rocky Mt. Bristle coneP. aristata

Great Basin Bristle coneP. longaeva•Limited experience 

at 1 year they are 

too small to survive 

inoculation.•Grow for two years 

before Inoculation•No MGR

Not Plug and Play Species

•Kept for a year in family groups •Toss susceptible at pycnia•Sorted by bug, no bugs

Tree No. Inoc 1-05 Susc Ex. 1-05

Inactive Rust, No bugs kept % Kept 06

76 29 26 15 58%79 25 21 12 57%82 28 27 8 30%459 28 11 0 0%460 25 20 1 5%487 24 21 0 0%567 30 29 11 38%568 30 29 16 55%569 18 17 8 47%571 27 27 0 0%790 28 28 19 68%791 30 17 7 41%881 30 24 0 0%998 18 16 6 38%999 27 10 6 60%

Tree No. Inoc 1-05 Susc Ex. 1-05

Inactive Rust, No bugs kept % Kept 06 2005 %MGR

76 29 26 15 58% 3%79 25 21 12 57% 16%82 28 27 8 30% 4%459 28 11 0 0% 0%460 25 20 1 5% 0%487 24 21 0 0% 0%567 30 29 11 38% 0%568 30 29 16 55% 0%569 18 17 8 47% 0%571 27 27 0 0% 0%790 28 28 19 68% 0%791 30 17 7 41% 24%881 30 24 0 0% 0%998 18 16 6 38% 0%999 27 10 6 60% 40%

Tree No. Inoc 1-05Suscpt. Ex. 1-05

Inactive Rust, No bugs kept

Ex. 1-05 % Suscpt.

Inactive rust 06

Ex. 2-07% Suscpt.

inactive rust 08

76 29 26 15 58% 74%79 25 21 12 57% 55%82 28 27 8 30% 50%459 28 11 0 0% -460 25 20 1 5% -487 24 21 0 0% -567 30 29 11 38% 32%568 30 29 16 55% 40%569 18 17 8 47% 50%571 27 27 0 0% 0%790 28 28 19 68% 13%791 30 17 7 41% 25%881 30 24 0 0% -998 18 16 6 38% 69%999 27 10 6 60% 25%

•3 years after 

inoculation a number of 

the infected trees  are 

still living

P. aristata, and P. longaeva

Limber

Foxtail

White Bark

High Elevation Pines

•Inoculated White Bark, 

Foxtail, and Limber last year•No MGR•Not plug and play

CGR, Complex Gene Resistance

•1 year after positive 

rust, surviving •No MGR•CGR

White Bark Limber

Foxtail

•No survivors•SWWP with CGR from Sacramento 

Mountains•Not seen in other population of 

SWWP

Foxtail•Theory of population proximity to 

Pinyon and Pinyon rustCronartium occidentale•All but one of the families are from 

the Northern population

•CGR has not been seen in Sugar 

pine •Was it there and we just didn’t 

see it? •We didn’t know to look for it but 

I don’t think it was there•Decades of inoculating SP, 

1,000’s looked at•Sort by Susceptible and Resistant•When tossed the susceptible 

racks, I was tossing racks full of 

dead or pycnia seedlings•Unlike the SWWP, nothing out of 

the ordinary 

What about Sugar pine?

•It’s not common for Sugar pine and Pinyon to 

grow in close proximity •2010 collection of sugar pine in close range 

of Pinyon• Will we see CGR in this SP population.

CGR in Sugar Pine

Ex. 7-07 Needle score, Type of spots, present in stem

Score Date 6 /2010

Participants: ADM, DRV, PM

Presence of ndl. infect.

Needle Score Status Spot count Spot color

Needle cast Stem infec. Lesion location Bugs

0= No WPBR F=fleck 1= alive 0=0 R=red 0=No cast 0=None 6=lesion 0=None 0=no bugs

1= 1-5 Y=susc. 2= dead 1=1-5 W=yellow1=purple needle cast

1=discolore d

7= aborted lesion 1= cot. 1=adelgid

2= 5-10 ?=unk.3= dead rust 2=5-10 B= >1

2=brown needle cast 2=swelling 2= mid. 2=scale

3= 10-20 3=10-20 P=purple

3=both color needle cast 3=both 3=top 3=both

4=20+ 4=20+ - =None 4=pycnia 4= two areas5=aecia 5= whole tree

6/2010

Family TreeRust

presence Spots count Spots Needle Stem Lesion

no. no. 9-NovNeedle score Status 1o 2o Color Cast infec. Location Bug comment

55 2 2 y 1 1 0 w 1 2 255 3 1 y 1 0 0 0 4 255 4 3 y 1 0 0 2 1 055 5 3 y 1 3 0 w 2 4 055 6 3 y 1 3 0 w 1 4 055 7 4 y 1 4 0 w 2 4 055 8 4 y 1 4 0 w 1 2 0

•We know that older trees have a greater ability to “tolerate “ WPBR•We’re not looking at tolerance here, we’re seeing resistance•Mechanism of MGR is collapsing the infected needle cells•Indications are that CGR works the same by collapsing infected cells •A small tree heavily infected in a sense will kill itself in the

process of saving 

itself•Will we pick up more CGR in older trees Inoculated with secondary needles?•Enough mass to be able to survive the process of killing infected tissue , but  

enough mass to survive

High Elevation Pines Secondary needles Inoculation

Ex. 2-07 SWWP CGR

Ex. 1-05 SWWP - CGR, Today 2010

SWWP Susceptible Five Years After Infection

The next Step, Histology

Thank You

Collaborators:

Co-IP:Tricia Maloney

Field Crew:Tom BurtCamille JensenPete Taylor

USDA, FS, PSW, Institute of Forest Genetics

BLM, SNPLMA, Southern NV Public Land Mgmt. Act