56 U.S. DEPT. OF AGRICULTURE MISC. PUB. 93 9 



year's shoots. Needles become short and curved and shed earlier than 

 normal, so that foliage is thin. Affected branches and, rarely, the en- 

 tire tree is transformed into witches'-brooms. Causes large-scale mor- 

 tality, particularly in young trees, or death of affected branches in 

 large trees. 



The rust is known only as pycnia and aecia on deodar. Pycnia 

 abundant, superficial, 0.08 mm. broad, 0.04 mm. deep. Aecia 10 to 12 

 on each needle on upper surface, in one row on one or the other side 

 of the middle line, but at distal end in two rows. Aecia are superficial, 

 up to 0.5 mm. broad and 0.16 mm. deep. Aeciospores in chains, yellow 

 with orange-yellow granular contents, round or oval, 15-21 X 14— 17/x. 

 The epispore is thick and striated. The aeciospores ripen in May- 

 June. Pseudoperidium is delicate, 1-cell thick, and falls apart soon. 



This is a serious disease of deodar in the western Himalayas in 

 India, particularly under wet conditions. Overwintering of aecio- 

 spores does not occur. The fungus overwinters as mycelium in the 

 needles and in the shoots containing them, to infect new needles in 

 the next season. 



Systematic removal of diseased plants or affected branches has been 

 found to bring the disease under control. 



Deodar is grown as an exotic in America and elsewhere. Importa- 

 tion of living plant material other than seed should be forbidden in 

 foreign lands. 



Hosts : Pinaceae — Cedrus deodara Loud. 



Literature : Troup, R. S. Peridermium cedri as a destructive f uneras. 

 Indian Forester 38:222-223. 1912. Ibid., 40:469-472. 1914. 



Chir Pine Blister Rust 



Cronarthwn himalayense Bagchee. A stem rust of chir pine (Pinus 

 roxburghii Sargent) , a 3-needle pine in west Himalayas (India) . The 

 symptoms include resin bleeding, cankers, and cracking bark. Plants 

 become dwarfed with poorly developed needles which shed early. 

 Pycnia of pinhead size appear through the bark and exude orange- 

 yellow fluid. Later, abundant aecial cups burst through the ruptured 

 bark as orange-yellow blisters. 



Cronartium Mmalayense is a heteroecious rust. Pycnia and aecia 

 occur on chir pine ; and uredia, telia, and basidia on Sioertia elata, S. 

 angustifolia, and S. cordata. Pycnospores are hyaline, oval, 3-5 X 

 1.5-2.3)U. Aecia are cylindric, 4 to 12 mm. long, 2 to 6 mm. broad 3 with 

 a persistent peridium which ruptures irregularly at the sides when ma- 

 ture. Aeciospores are orange yellow, oval, 22-31 X 13-19/x with a 

 thick, verrucose wall, and develop in chains. They infect swertia sit- 

 uated within 2 to 3 miles. 



Orange-yellow uredia appear on leaves and stems of swertia and 

 are subepidermal. Uredospores are orange yellow, oval, thick-walled, 

 spiny, about 22 X 16/*. They reinfect swertia. Telia develop later 

 in the uredia or form separately. Teliospores are columnar, hairlike, 

 up to 3 mm. long and 0.1 mm. broad, germinate in situ into 4-celled 

 promycelium, each cell developing a sporidium, borne on a sterigma. 

 Sporidia are hyaline, globose, 5.5 to 6.5/x broad. They infect pines oc- 

 curring within a range of 200 yards. 



The disease causes mortality particularly to young plants in planta- 

 tions and less so in natural forests. Older plants are less susceptible 



