OVERWINTERING 



Like the other Cronartium rusts of pines, C. 

 comandrae overwinters as myceUum in Hve bark of its 

 pine hosts, and aeciospores may be produced from 

 the same canker for many successive years (Arthur 

 1929 and Hedgcock and Long 1915). Being an obli- 

 gate parasite, C. comandrae dies along with its host, 

 but the two commonly survive together for a few 

 years or even a few decades. In some unusual 

 instances the mycelium of a single canker may remain 

 active for more than a century (KrebUl 1965). Aecial 

 production in long-lived infections often is Limited 

 and may not occur in many years, especially when 

 mycelium is in bark that is not very active physio- 

 logically. In the form of its long-lived mycelium, C. 

 comandrae can exist for long periods in pine stands 

 even when there is no new infection. 



C. comandrae is unable to overwinter in 

 comandra in mountain areas near susceptible pines. 

 Infections on stems of comandra are common, but 

 microscopic examination indicates that the rust 



fungus does not grow down the stems into rhizomes. 

 Thus when the shoots die in the fall, the comandra 

 plant is freed from the rust. Indeed, transplants of 

 severely infected comandra collected in fall from 

 Cache and Teton National Forests sprouted free of 

 rust in Logan the following spring. Likewise, experi- 

 mentally infected comandra have always sprouted 

 free of rust after overwintering outdoors in Logan. 



Although there is no field evidence to sug- 

 gest that C. comandrae can overwinter in the moun- 

 tains, it may possibly overwinter free from pines in 

 the Great Plains of eastern Colorado (Bethel^). The 

 mode of such overwintering is unknown and the 

 observations reported could even be misinterpretation 

 of long-distance dissemination of aeciospores or 

 urediniospores. 



Bethel, E. Some early collections of west American 

 fungi. Unpublished manuscript, filed in Intermountain Forest 

 and Range Exp. Sta., Login, Utah. 1925. 



PHENOLOGY OF LODGEPOLE PINE, COMANDRA, AND 

 CRONARTIUM COMANDRAE IN THE ROCKY MOUNTAIN STATES 



Development of comandra bUster rust and 

 the corresponding development of comandra and 

 lodgepole pine were studied from 1962 to 1966 in 

 the western part of the Rocky Mountain States. 

 Several plots for which general phenology data were 

 recorded are listed below. The plots are named for 

 the National Forests in which they are located. 



Teton-Wyoming, near Goosewing Guard Sta- 

 tion in the Gros Ventre River drain- 

 age south of Kelly at 7,250 feet 

 with a southern aspect. 



Targhee-Idaho, near Pine Creek north of 

 Swan Valley at 5,850 feet with a 

 southern aspect. 



Bridger-Wyoming, near Fremont Lake east 



of Pinedale at 8,500 feet with a 



western aspect. 

 Sawtooth-Idaho, on Cassia Plateau west of 



Oakley at 7,400 feet on a slight 



northwest slope. 



Wasatch-Utah, near Beaver Creek east of 

 Kamas at 7,500 feet elevation on a 

 slight southwest slope. 



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