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Canada Thistle Rust - Puccinia punctiformis
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Non-native Species Global Rank :
GNR
State Rank :
SNA
(see State Rank Reason below)
Agency Status USFWS :
USFS :
BLM :
External Links
State Rank Reason (see State Rank above)
Puccinia punctiformis was accidentally introduced into North America (Winston et al. 2012). It is widespread throughout the United States of America (USA) and Canada. A conservation status rank is not applicable (SNA) because Puccinia punctiformis is a non-native rust in Montana that is not a suitable target for conservation activities.
General Description
Canada Thistle Rust (
Puccinia punctiformis ) is a fungus, specifically a type of rust in the Family Pucciniaceae.
Canada Thistle Rust infects the root system of Canada Thistle (
Cirsium arvense ), a noxious and non-native plant, and kills its leaves (
Montana Biological Weed Control Coordination Project ). The rust produces four types of spores (Winston et al. 2012). The urediospores are visible in spring, and can be found on the thistle's stems and upper surfaces of leaves. The urediospores are dense golden-orange pustules. In the fall brown rust colored teliospores are produced in preparation for winter.
Range Comments
Canada Thistle Rust is widespread throughout the USA and Canada (Winston et al. 2012).
Observations in Montana Natural Heritage Program Database
Number of Observations: 16
(Click on the following maps and charts to see full sized version)
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Relative Density
Recency
(Observations spanning multiple months or years are excluded from time charts)
Habitat
HOST PLANT
Ecology
DAMAGE TO PLANTS [Adapted from Winston et al. 2012;
Field Guide for Biological Control of Weeds in Montana ]
Spores of Canada Thistle Rust germinate on leaves and the fungus travels through the stem to infect the root system. Infected roots cannot effectively drawn nutrients from the soil, which results in weakened plants. The rust can stunt the growth of young Canada Thistle plants, but it does not provide significant population control.
PLANT-ANIMAL INTERACTIONS Some thistle biological control insects can disperse Canada Thistle Rust (Winston et al. 2012).
Reproductive Characteristics
LIFE CYCLE [Adapted from Winston et al. 2012]
Management
BIOLOGICAL CONTROL [Adapted from Winston et al. 2012; NRCS 2019)
A fair amount of preliminary work and an array of factors must be considered when developing a biocontrol plan for controlling thistles. Readers are encouraged to consult the "Useful Links" and cited literature in this profile.
Canada Thistle Rust was accidentally introduced into the USA and Canada. It is still being researched as a potential future Canada thistle biological control agent and is not fully approved for re-distribution within the USA and Canada. Since 2017 it has been intentionally moved to uninfected Canada Thistle infestations and is being monitored.
Useful Links: Montana Biological Weed Control Coordination Project Field Guide for Biological Control of Weeds in Montana Stewardship Responsibility
References
Literature Cited AboveLegend:
Web Search Engines for Articles on "Canada Thistle Rust"
