298 Bulletin 145. 



(c.) Conditions faiwring the disease. — The knife is our only lope of 

 extermination, but there are undoubtedly conditions ' .ich favor 

 the disease. In a succulent, rapidly growing tree t'^ . bacteria find 

 more favorable conditions for their development than in one which 

 grows slowly, yet with sufficient vigor. For this reason too much 

 nitrogenous manure is dangerous, and, for the same reason, a succu- 

 lent growth induced by severe pruning sliould be avoided. It has been 

 demonstrated by experiment that withholding water from potted trees 

 which had been inoculated with blight would immediately stop the 

 course of the disease. 



References to Literature.* 



Arthur, J. C. — Pear Blight. Report N. Y. State Experiment Station, 

 1884, pp. 357-367- 

 Pear Blight, Bulletin 2, New Ser., N. Y. State Experiment Station. 

 Proof that bacteria are the direct cause of the disease in trees known 

 as pear blight. Proc. Amer. Assoc. Adv. Sci. , XXXIV., 295-298, 

 1885. [Same in Bot, Gaz. X., pp. 343-345, 1885.] 

 Pear Blight. Report N. Y. State Experiment Station, Geneva, 1885, 



pp. 241-248. 

 Pear Blight and Its Cause. Amer. Nat., XIX., pp. 11 77-1 185, 1885. 

 History and Biology of Pear Blight. Proc. Phila. Acad. Nat. Sci., 



1886, pp. 322-^342. 

 Pear Blight. Report N. Y. State Experiment Station, 1886, pp. 275- 

 289; also '' Important Articles on Pear Blight," same report, pp. 

 300-315. 

 Beckwith, M. H.— Blight affecting the body of pear and apple trees. 



Report Delaware Experiment Station, 1895, pp. 158-159. 

 BURRILL, T. J. — Anthrax, of fruit trees or the so-called fire blight of pear 

 and twig blight of apples. Proc. Amer. Assoc. Adv. Sci., 



XXIX., pp. 583-597. 



Blight of Pear and Apple Trees. Report Industrial University of 



Illinois, 1880, pp. 62-84, 

 Pear Blight, Amer. Naturalist, XV., pp. 529-532, 1881. 

 Trans. 111. Hort. Soc, 1880, pp. 157-168. 

 Bulletin 2, Illinois Experiment Station, pp. 16 and 17. 

 Clark, J. W. — Pear or Fire Blight. BuUedn 16, Missouri Experiment 

 Station. 



* For earlier references see Arthur, J. C. Important Articles on Pear 

 Blight. Report N. Y. State Experiment Station, 1886, pp. 300, 315. 



