Extension Note BC Journal of Ecosystems and Management British Columbia’s Forests White Pine Blister Rust Forest Health Stand Establishment Decision Aid

Stefan Zeglen1, Richard Hunt2, and Michelle Cleary3 Introduction

White pine blister rust (Cronartium ribicola) is an introduced disease affecting five-needle pines throughout North America. Like other non-native pests, its impact on the native hosts has been dramatic, decimating species such as western white pine in both number and distribution. Because of its prevalence, white pines have been removed from commercial forestry consideration in most areas. This is unfortunate as western white pine is an excellent substitute for Douglas-fir in areas prone to laminated root disease. It can also command a premium price. To mitigate disease impact and permit management, a good understanding of the biology of C. ribicola is necessary. The Stand Establishment Decision Aid (SEDA) format has been used to extend information on various vegetation and forest health concerns in British Columbia. This decision aid summarizes information that relates current management regimes to the spread and effects of white pine blister rust. The first page provides general information, hazard ratings for the biogeoclimatic zones and subzones of British Columbia, and biological considerations for white pine blister rust. The second page outlines the implications to silviculture and the various techniques used to manage the disease. This page also includes a resource and reference list to provide readers with more detailed information. Reference material that is not available online can be ordered through libraries or the Queen’s Printer at: www.qp.gov.bc.ca Acknowledgements The preparation and publication of this decision aid was supported by the British Columbia Ministry of Forests and Range through the Forest Investment Account–Forest Science Program and by the Canadian Forest Service. keywords: Cronartium ribicola, forest health, forest management, pine stem rust management, Ribes spp., white pine blister rust.

Contact Information 1 Forest Pathologist, British Columbia Ministry of Forests and Range, Coast Forest Region, 2100 Labieux Road, Nanaimo, BC V9T 6E9. Email: [email protected] 2 Research Scientist (retired), Canadian Forest Service, Pacific Forestry Centre, 506 West Burnside Road, Victoria, BC V8Z 1M5. 3 Forest Pathologist, British Columbia Ministry of Forests and Range, Southern Interior Forest Region, 515 Columbia Street, Kamloops, BC V2C 2T7. Email: [email protected]

article received: June 7, 2007 article accepted: February 5, 2009

JEM — Vo l u me 10, Nu m b e r 1 Published by Forrex Forum for Research and Extension in Natural Resources Zeglen, S., R. Hunt, and M. Cleary. 2009. BritishJEM — Columbia’s Vo l u me 10, forests: Nu mWhiteb e r 1 Pine Blister Rust Forest Health Stand 97 Establishment Decision Aid. BC Journal of Ecosystems and Management 10(1):97–100. www.forrex.org/publications/ jem/ISS50/vol10_no1_art9.pdf zeglen, hunt, and c l e a ry

tissue,

the

the

in

uredinial, spore leaf

(see

of host

evident leaf

which

into

hairlike

five and no in cycle

the

host ,

as

has grow on

colonize transfer with

alternate

to period by

and temperature asexual

the place develop alternate

the of in and

latent hosts the

begins

eventually

telia occurs

a

continues

macrocyclic a heteroecious, is on

two

and leaves

remain

moisture the

completing pustules,

infections basidial

beginning

which requires stomata

aecial Pinus on and pycnial reproduction development host, proper

invade

these and

that

pine

rust Cronartium ribicola stages: telial, 1). Figure foliage to basidiospores of the transfer with enters fungus The germination. subsequent and through commences host the pine on infection conditions, spots infection red to distinct yellow creating often bands. or if infected needle directly stem is (or branch attached) fungal symptoms. outward aeciospores orange containing which blisters from these spores in spring, Wind-dispersed appear. several kilometres travelling durable, relatively are the infected Often, host. alternate an colonize to after long the canker to attached needle remains died. has foliage other shortly form pustules the stomata); through (again spread that urediospores short-lived releasing after the disease intensify over and foliage adjacent to the summer. columns underside. to back travel that dispersed basidiospores a at delayed is timing Life-cycle summer/fall. late higher elevations. mass exuded a sticky (spermatia) as pycniospores aecia before a year often margin the canker at act as exudate to attracted Flies development. vectors. Life cycle • • Given • Successful • Infected canker a visible create to swell tissues • Aecia • From wind- four, • Each producing germinates, teliospore • Sexual ), (Pinus pine white monticola Western in proximity host) species (the alternate fusiform forming infected tissues of swelling

trees. other and pines Non-five-needle margins, canker around forming droplets pyncial Guidebook). Management Rust Stem Pine on m on 1000 above elevations at declines rating Hazard are the Coast.the higher cankers steeper the The slope, selected not for trees particularly on in the crowns, found harvesting. early consider sites, On such resistance. species pine highly susceptible containing Stands pine). white wild(e.g., western the increases species greatly susceptible 30 m) to (within infection. of hazard alternate confirmed species are (paintbrush) Castilleja the disease these on needs hosts of impact The hosts. further evaluation. Symptoms: on bark roughened pitch, streaming with often cankers cankered on foliage necrotic and dead) cankers, (often old flagging”). (so-called “red branches Signs: in blisters in ruptured aeciospores orange bark, orangish the of foliage on structures telial uredial and and spring, host. alternate occurs Death when vertically horizontally. than faster insects) fungi invade and (other secondary organisms aecial through ruptures. often cankers, infect the never stem. 60 cm away than those more stem;

all ), and flexilis (P. pine ), limber albicaulis (P. pine whitebark America. North to native pines five-needle other Immune: Highly Susceptible: Hazard rating (based Columbia British • Hazard high is throughout rating rating. • Biogeoclimatic hazard effect on known no has zone Host information Susceptible stand characteristics • • Presence Ribes of and (lousewort) • In Pedicularis some northern Idaho, Signs and symptoms • • growing • Diamond-shaped annually, expand cankers stem the into • Cankers mycelia spread can stem 30 cm of within Norm Alexander Norm

an

is

in survive

that

to

Mexico. passed

host

fungus in

was live

a

reported

non-native

requires a

, been

and

yet

not

parasite

has

across spread WPBR in Estonia, ) planted Cronartium ribicola in originated likely It 40 years. in about Europe known. not is exact location an although Asia, strobus obligate reproduce. and Europe. seedlings of from also via shipments 1915, WPBR before locations other possibly America, North (1906) in eastern earlier appeared BC) and America (Vancouver, North western limber in the (on east Dakota South to pine) pine) southwestern (on Mexico New to and pine), disease Act Quarantine the Plant pines, Canada. and whitebark in the north (on Columbia British from The in the south. pine) sugar California (on and the 1 prohibited Number 1912; Quarantine States the United to 5-needle pines of importation all of throughout affected is pine white Western range. its by caused is • White rust (WPBR) blister pine General information seedlings• Introduced into pine white eastern on • First (P. pine white eastern in 1854 on reported • Because white eastern on WPBR the effect of of ranges • The distribution American North western Infected western white pine displaying streaming pitch Infected western white pine branch flagging. from a canker and multiple White Pine Blister Rust Blister Rust White Pine

98 JEM — Vo l u me 10, Nu m b e r 1 w h i t e pine blister rust

that program eradication very to susceptible ) are Winter regenerate. to spp. seed germination. seed coastal This be reforestation. used characteristics. should for growth superior the In orchard. Idaho or interior an from stock 1000 m, use resistant Above better (65% or orchards Idaho or Columbia British from material use only Interior, canker-free). Ribes a massive conducted the 1970s, the Americans to Up 25 years. for been sought have pines white western resistant Columbia, British In by conferred (possibly small cankers growing slowly selections: (1) have Resistant and age by (conferred disease resistance developmental (2) have or “polygenes”); gene). major, or dominant, a single by (conferred clean” “totally (3) are or elevation); seed selections. Resistant Idaho and interior have orchards interior selections and available. is still seedlings retain that 50–100% “clean” produce to used in coastal seed orchards them. However, eliminating difficulty of the extreme to due failed in the West largely be can verylocal eradication effective. (Ribes currants black nigrum Generally, local rust hazard. currant black commercial Rust-resistant, so. less are WPBR, while currants red powdery to mildew. a susceptibility poor and yields show frequently cultivars available. are currants ornamental Several resistant, seedbed. Low inviting a less provides and disturbance ground logging reduces which reduces levels, light low maintaining thus canopy retain removals volume seed germination. partial disturbance inconsistent; quite is effectiveness seedbanking, this method’s Ribes increase may these species. of diversity the genetic retain to harvesting operations GENETIC RESISTANCE GENETIC Alternate host eradication • Regeneration/establishment • coastal have types;• Seed two coastal the first orchards of composed are orchards in the Cascade identified (Cr2) trees is Range resistant gene • Pollen major from the increase may their cultivation but crop, • In popular a are currants areas, some • Harvesting Ribes of the ability affect greatly practices Disease management are actions the following stands, pine white rust-susceptible managing For standards. meet stocking to recommended Harvestingsite preparation and reduce to advocated previously was • Although preparation site for fire the use of be during cut not should pines limber • If and whitebark threatened possible, Canadian Forest Service; Typical diamond-shaped Typical spring. canker in the Life cycle of white pine blister rust (Source: 1. f i g u r e Richard Hunt photo, top). White Pine Blister Rust Blister Rust White Pine

JEM — Vo l u me 10 Nu m b e r 1 99 zeglen, hunt, and c l e a ry

ociety ociety management

for

(Accessed A case history. www.pfc.forestry.ca/ atural Resources S Resources atural uite 702, 235 1st Avenue, Avenue, 702, 235 1st uite implications

blister pine white and , pines, , S esearch and and Research for Forum and

Ribes rrex nternet without the written consent consent written the without nternet xtension in N in xtension Fo Forrex g pathology,

ditor, Editor, Managing Biology,

Forum for Research and E and Research for Forum 2009). February (Accessed species:

rrex Fo does not warrant their accuracy or reliability, and expressly disclaims any liability liability any disclaims expressly and reliability, or accuracy their warrant not does contact: consents, . For rrex rrex 1488-4674. Articles or contributions in this publication may be reproduced in electronic electronic in reproduced be may publication this in contributions or 1488-4674. Articles Fo Fo esources Society, Province of British Columbia, and Her Majesty Majesty Her and Columbia, British of Province Society, Resources xtension Natural in issn in relation thereto. relation in The information and opinions expressed in this publication are those in and of expressed thisopinions authors The thepublication information respective and Kamloops, BC V2C 3J4, or email [email protected] email BC V2C 3J4, or Kamloops, and of all contributing copyright owners. This publication and the articles and contributions contributions and articles the and publication This owners. copyright contributing all of and I the over public the to accessible made be not may herein 2009 Copyright in this article this is© 2009 Copyright in property the of of or print form for use free of charge to the recipient in educational, training, and not-for- and training, educational, in recipient the to charge of use free for form print or However, acknowledged. fully are authorship and source their that provided activities profit use other any or media, or forms other to application translation, adaptation, reproduction, the requires redistribution, or use, resale, commercial for part, in or whole in works, these of of consent written E Service Forest Canadian Canada, Resources Natural Canada, Queen of the right in

2009). February 10:514. rust. HortTechnology diseases/CTD/index_e.html m www.for.gov.bc.ca/tasb/legsregs/fpc/fpcguide/pinestem/pine-toc.ht BC. Practices Code, Victoria, guidebook. Forest rust management stem 1996. Pine 1:73–85. BC. Victoria, Service, Centre, Forestry Pacific Forest Canadian Report BC-X-397. BC. Information Victoria, Service, Centre, Forestry Pacific Forest Service BC and Forest Ministry Canadian ed. 2nd of Columbia. in British damage 17. No. II Rep. BC. FRDA Victoria, Forests, 35:87–109. Review Phytopathology Annual of press. In Pathology. rust. Forest blister pine white of PNW-584. Publication Extension Northwest Pacific press. In Pathology. America. Forest North in western 2000. Introduction: R.A. K.E. and Sniezko. Hummer, in Mycology Developments Research rust. Recent blister pine R.S. White 2003. Hunt, Parks. and Lands BC and Ministry Environment, of Ministry Forests of Columbia British Resource and reference list and reference Resource Columbia. diseases tree British of 1996. Common Wallis. G. and Morrison, Allen, E., D. Canadian Columbia. British for pines white western ______. 2006. Blister-rust-resistant Minn. diseases. Paul, St. APS, conifer of Lewis. 1997. Compendium K.J. E.M. and Hansen, forest guide to 2001. Field Pollard. A. and Westfall, E. Allen, J. Ebata, T. J., Henigman, America: in North rust control blister pine 1997. White O.C. Maloy, Idaho, of University pine. white western Pruning 2006. Schwandt. J.W. C.C. and Schnepf, pines five-needle of management [2009]. Silvicultural H. Merler. and Pronos, Zeglen, S., J. [2009]. Ribes P.J. Zambino,

ds stan

rs ol o uning r ontr tect c o r l cising d p and

es p ex

gica unacceptable. the bole are 60 cm from floral ornamental if sold as revenue providing product forest a non-timber are boughs stubs. branch long leave do not pickers that Ensure greens. (Coast) the 65% live or of 50% (Interior) to up 1–2 m, removing reaches height stand reach when trees pruning the second Conduct whorls). live three least at (leave crown log, in the wood first quality ensure To crown. the live 50% of least at 4–5 m, removing possible. lift is third optional an disease. root of the number reduces foliage susceptible of removal early 2 m; therefore, in the first stock. resistant with when regenerating be required not should Pruning infections. fatal decay. contain thinning because as infections WPBR increases pruning without thinning However, per hectare. stems 700 Retain about increases. circulation spore and airflow increases, registered (not triadimefon However, protection. ineffective or limited provide most seedlings nursery and to when applied stock protection some in Canada) provides planting. during however, cankers; inactive or declining with associated ) is maxima (Tuberculina been used control. a biological as successfully fungi have other this nor neither foliage susceptible from spores block which physically Enclosed seedling protectors, continue. Tests promise. show years, growing the early during surrounding tissue cambial and bark the live Remove locations. highly visible or parks the 20 cm past and the side edge leading 5 cm past least at canker a stem of the margin thestem. halfway around than more spread not have those that of edge bottom and top boundary. the canker define to will bark help Moistening iolo ing eedl d Fungici B Thinning Canker S than less infections branch or stem with trees that • Free-growing state criteria damage Trimmed stripping. bark to • Consider due lessen damage tree to pruning autumn when average pruning the first Conduct recommended. is system a two-lift • Currently, Armillaria of • Resin-producing be confused symptoms might with basal cankers stem occur WPBR. infections Over• Lower of 85% of the incidence reduces pruning branch may basal old cankers cankers; stem with trees • Mountain prefer beetle pine may cankers, kill or established • Although protection prophylactic several offer chemicals Other effects and associations • Other WPBR. with Purple mould compete and fungi cankers will parasitize culls and infected uninfected ones. trees protects • Thinning pine non-resistant • Stand tending in be high-value trees to restricted should • As it time consuming, is excision canker White Pine Blister Rust Blister Rust White Pine

100 JEM — Vo l u me 10, Nu m b e r 1 Test Your Knowledge . . .

British Columbia’s Forests: White Pine Blister Rust Forest Health Stand Establishment Decision Aid

How well can you recall some of the main messages in the preceding Extension Note? Test your knowledge by answering the following questions. Answers are at the bottom of the page.

1. From what seed sources should resistant seedlings be grown?

2. Which silviculture treatments are most effective for protecting white pine?

3. How does white pine blister rust differ from pine stem rusts on lodgepole or ponderosa pines?

ANSWERS

alternate host. alternate

pine stem rust that transfers directly between pines without requiring an an requiring without pines between directly transfers that rust stem pine

life cycles are identical to WPBR. Western gall rust, however, is a hard hard a is however, rust, gall Western WPBR. to identical are cycles life

. Although the hosts differ, the the differ, hosts the Although . Cronartium genus the from also are rusts,

Stem rusts of hard pines, such as comandra and stalactiform blister blister stalactiform and comandra as such pines, hard of rusts Stem 3.

valuable individual trees. individual valuable

of infection or to remove infected branches. Excise cankers to protect protect to cankers Excise branches. infected remove to or infection of

the alternate hosts to reduce local rust levels. Prune to reduce the risk risk the reduce to Prune levels. rust local reduce to hosts alternate the

Select resistant stock for planting. Thin out infected trees or remove remove or trees infected out Thin planting. for stock resistant Select 2.

available from the Bailey Seed Orchard near Vernon. near Orchard Seed Bailey the from available

parentage from Idaho sources should be used. Seed for these trees is is trees these for Seed used. be should sources Idaho from parentage

have this type of seed available. For interior stock, seedlings that have have that seedlings stock, interior For available. seed of type this have

gene resistant (Cr2) seed sources should be used. Several coastal orchards orchards coastal Several used. be should sources seed (Cr2) resistant gene

For coastal stock, seedlings that originated from nurseries using major major using nurseries from originated that seedlings stock, coastal For 1.

98 JEM — Vo l u me 10, Nu m b e r 1