January 26, 1917] 



SCIENCE 



93 



SPECIAL ARTICLES 



THE ROOT-ROT DISEASE OF THE APPLE 

 IN VIRGINIA 



An unusually destructive rotting of the roots 

 of apple trees is prevalent in the chief orchard 

 sections of Virginia. The infectiousness of 

 this condition is shown in the death of adjoin- 

 ing trees in groups of considerable numbers 

 irrespective of soil conditions or topography 

 and the death of replants set in holes from 

 which rotted trees were removed. 



The symptoms of this disease have been 

 known for some time, but the causative organ- 

 ism has not been determined. 



Isolations from diseased roots by the writers 

 from a number of orchards in the " Valley " 

 and " Piedmont " sections of the state have 

 yielded cultures of an imperfect fungus which 

 appears to be the conidial stage of a species of 

 Xylaria. Inoculations made from pure cul- 

 ture of these isolations into bark wounds of 

 living apple roots in both damp chambers and 

 in the field have produced typical rotting of 

 the bark and wood, and the introduced fungus 

 has been obtained in pure culture from the 

 margins of these infected portions. 



Eecently perithecial stromata of Xylaria 

 polymorpha (Pers.) Grev. have been found on 

 roots of apple trees in various stages of typical 

 root-rot attack and on the stumps of several 

 deciduous trees in a small patch of woodland 

 immediately adjoining the orchard in ques- 

 tion. Cultures obtained from germinated 

 ascospores of this fungus are being used for 

 additional inoculations into apple roots. 



Pending the results of these inoculations, it 

 seems reasonably certain that a species of 

 Xylaria is responsible for the root-rot disease 

 of the apple in Virginia. It is possible that 

 more than one species of Xylaria is involved, 

 since certain constant cultural distinctions 

 exist between some of the isolations; these, 

 however, may be varietal rather than specific. 



Apparently all varieties of the apple are 

 susceptible and probably equally so. Obser- 

 vations indicate that the disease may be spread 

 in cultivation or in the removal of borers, in 

 contact between roots systems of diseased and 



healthy trees, and by surface washing of spores 



or other infective material. 



P. D. Fromme, 

 H. E. Thomas 

 Virginia Polytechnic Institute 



THE AMERICAN MATHEMATICAL 

 SOCIETY 



The twenty-third annual meeting of the Ameri- 

 can Mathematical Society, which was held at Co- 

 lumbia University on Wednesday and Thursday, 

 December 27-28, 1916, was in several respects an 

 exceptional occasion. It took place in the midst 

 of the convocation week series of meetings of the 

 American Association for the Advancement of Sci- 

 ence and its long train of afiSliated societies, and 

 was immediately followed by the second annual 

 meeting of the newly organized Mathematical As- 

 sociation of America, with which the society has 

 not only a large common membership, but also a 

 general community of interest highly beneficial to 

 both. The annual meeting is always one of the 

 largest of the year, being the season of the elec- 

 tion of officers and other members of the council 

 and the transaction of important business. This 

 year it was especially marked by the delivery of the 

 retiring address of President E. W. Brown, of 

 Yale University, who chose as his subject "The 

 relations of mathematics to the natural sciences." 

 This was presented before a joint session of the 

 American Mathematical Society, the Mathematical 

 Association of America, the American Astronom- 

 ical Society, and Section A of the American As- 

 sociation, and was followed by the retiring address 

 of Yice-president A. O. Leuschner, of Section 

 A, on "Derivation of orbits — ^theory and prac- 

 tise. ' ' A joint dinner of four organizations was 

 held on Thursday evening at the Park Avenue 

 Hotel, with an attendance of 143 members and 

 friends. Much of the credit for the great success 

 of the meetings is due to the joint committee on 

 arrangements and to the program committees of 

 the Mathematical Association. 



Under all these favorable circumstances the at- 

 tendance at the four sessions of the society ex- 

 ceeded all previous records, the number of mem- 

 bers present being 131. President Brown occupied 

 the chair, being relieved by Vice-presidents Hed- 

 riek and Snyder and Professor G. D. Olds. The 

 council announced the election of the following 

 persons to membership in the society: Professor 

 H. H. Conwell, University of Idaho; Mr. Robert 



