DISEASES OF VARIOUS CROPS I381 



the results were always positive, even when substances of different source 

 and origin were used, isolated in several parts of the United States from the 

 different hosts of the parasite. 



Cultures of lucerne affected with Sci. Trifoliorum also causes rotting 

 of the fruits of the lemon tree, which, however, instead of turning straw yoi- 

 low as in the other cases, assumed a nut-brown colour. 



As means of control it is advised to wash the citrus fruits with an 0.02 

 per cent, solution of sulphate of copper. 



1038 -Black Rot of the Vine {Gu/gnard/a BidweJ//i) Attacking V/t/s rotun- 

 difolia and V. Munsoniana (Muscadine Grapes) in the United States of 



America. — See Xo. 987 of this Bulletin. 



103Q hypoderma deformans n. sp., Attacking the Lea,ves of Pinus ponde- 



rosa in the United States and Canada. — weir james r., in jomnai of Agricultural 



Research, Vol. VI, Xo. 8, pp. 277-288, Fig. 1-4, PI. XXXII. Washington, D. C, 1916. 



The writer describes as a new species, under the name of Hypoderma de- 

 formans n. ,sp., a fungus which attacks the leaves of Pintis pofiderosa lyaws. 

 in several parts of the United States and Canada : Montana, Oregon, Idaho, 

 Washington and British Columbia. 



The black, glossy apothecia, 10 mm. in length and about I mm. in 

 width, may develop in the form of a continuous or broken band over the en- 

 tire length of the leaf ; the asci are spindle-shaped, the spores olive green 

 in colour, transparent, slightly curved, with blunted tip, and have a septum 

 on reaching maturity- ; the paraph3^ses are numerous and thread-like, slightly 

 swollen at the tip. 



The end of the infected leaves turns yellowish brown, and this change 

 spreads more or less rapidly throughout the leaf until the final appearance of 

 the apothecia. The exact length of time between the first symptoms of the 

 disease and the ripening of the apothecia varies greatly, being sometimes 

 April-May to November ; it is occasionally prolonged until the followino- 

 spring. The apothecia may contain asci in all stages of development, so as 

 to produce ripe spores continually. The period of most intense spore form- 

 ation, however, is found to be in I\Iay and June, when rains are frequent 

 and when the plants have attained their maximum active growth. The leaves 

 attacked end by withering completely and falling, which causes manv 

 troubles and changes in the growth of the buds. One of the most conspicuous 

 phenomena consists of the appearance of very large "witch's brooms" 

 of a diameter of 1-2 yds and a weight exceeding one cwt. The formation 

 of these witch's brooms had been erroneously attributed to Razoumofskya 

 campylopoda (Engelm.) Piper (" yellow-pine mistletoe "), but they are cer- 

 tainly coimected with the presence of Hypoderma defoniiajis. The bran- 

 ches thus deformed are generally sterile. 



The disease not only attacks plants which have already attained a 

 certain growth, but also young nursery plants, causing the death of the lat- 

 ter when the attack is verv severe. 



