APPLE DISEASES 



483 



remove the cause, and root Injury is a 

 cause without which I do not believe 

 rosette will exist, yet root injuries are 

 not all from the same causes, and the 

 varied contributory causes are conditions 

 which precede the results and we must 

 strive to correct them. 



For instance, if there is a condition 

 where the root hairs are perishing for 

 lack of water, the remedy is more water. 



If the root hairs are being injured by 

 too much water, the remedy is less water. 



If there is underground seepage, the 

 remedy is drainage. 



If the roots are cramped by a hard 

 soil, the remedy is dynamite or alfalfa. 



If field mice or gophers injure them, 

 kill the mice and gophers. 



If the soil lacks humus, manure it. 



If it has too much alkali, wash it out, 

 or drain the land, if you can. 



If root injuries are caused by aphis, 

 kill the aphis. 



In every case of a resetted orchard I 

 have observed, where alfalfa or clover 

 has been sown, the conditions have been 

 improved. This would not correct the in- 

 jury where the alkali or other salts were 

 strong enough to kill the alfalfa. 



In case the cause is crown gall, or some 

 other form of gall, I have no knowledge 

 of a remedy which I could recommend, 

 but think that alfalfa or dynamite might 

 open up the soil and improve the con- 

 ditions. I have strong faith that alfalfa 

 will improve the orchard conditions in the 

 arid regions. 



Opinions from Tarions Sonrces 



In 1897 Cavara caused on the roots of 

 the vine, what he called "tuberculosis or 

 gall," by means of material which he had 

 shipped from Venice and from which he 

 made pure cultures and performed suc- 

 cessful inoculations. The following cita- 

 tions are from his article on the subject: 



"The plant attacked presents the fol- 

 lowing characteristics: 



"A rachitic development of the leaves. 

 Color of the leaf greenish yellow." The 

 work "ratchitic" means a bunching or 

 clustering of the leaves as in case of a 

 racime or spike. 



In this case then, we have a bunching 



of the leaves, a yellowing of the leaves; 

 this bunching and yellowing caused by 

 gall. 



In U. S. Bulletin No. 213, Bureau Plant 

 Industry, it is stated that an analysis of 

 sap from crown gall showed that it con- 

 tained an amount of acetic acid. See p. 

 174, Bull. 213. 



Professor J. W. Tourney, formerly of 

 the Arizona Station, said: "The warty 

 growth in crown gall is due to a vege- 

 table organism or slime mould fungus. 

 When these galls grow until they girdle 

 the trunk, they interfere with the move- 

 ment of the sap. Affected trees show 

 signs of starvation, yellowish foliage and 

 enfeebled growth. Young trees often die 

 of the disease." 



Here Professor Toumey describes some- 

 thing very similar to rosette, and affirms 

 that these conditions are due to crown 

 gall. 



The U. S. Bulletins with those of Cana- 

 da give the information that 485 species 

 of trees, shrubs and plants have been ob- 

 served to have galls, caused by insects, 

 rodents, birds, or other injuries, and give 

 a number of cuts showing the effects up- 

 on the leaves or branches, and the tend- 

 ency is always toward a resetted condi- 

 tion. 



The article on "Galls" in the new Ency- 

 clopedia Britannica shows that gall is 

 found in Europe on many of the forest 

 trees. I have found the same things In 

 the forests of this country, and on some 

 of the forest trees in the orchards of this 

 country, and have often been able to dis- 

 cover gall on the roots because of the 

 rosetted condition of the top first at- 

 tracting my attention. 



In North Carolina Bulletin No. 206 Pro- 

 fessor Smith says: "The presence of 

 woolly aphis on the roots may often be 

 detected from the outward appearance of 

 the trees. If badly infested, they usually 

 present a sickly appearance, indicated by 

 scant foliage of a yellowish color, and a 

 dwarfed growth. After the aphids have 

 been present for two or three years, the 

 roots become so badly weakened that the 

 entire tree may become loosened or 

 pushed over. Similar to all plant lice, the 



