ANOTHER IMPORTED TREE DISEASE 



739 



Hebrew for " holy," and the grove has undoubtedly been 

 preserved because of its sacred character. The natives 

 to-day will tell you that the grove is sacred because it 

 " was planted by Jesus Christ," a belief which finds the 

 semblance of justification from a poetical passage in the 

 104th Psalm referring to " the Cedars of Lebanon which 

 the Lord has planted." 



As the traveler stands on the summit of Lebanon, nearly 

 10,000 feet high, and looks down upon this ancient grove, 

 the remnant of a mighty forest, and upon the still more 

 ancient glacial moraine upon which it grew, and sees upon 

 the flank of Lebanon the ruins of ancient temples and the 

 vast expanse of the Mediterranean beyond, and to the east 

 the distant ruins of Syrian Baalbek, he may recall the 

 force of the words of Holy Writ, " all flesh is grass and 



as the flower of the field it perisheth." Over this ex- 

 panse, witnessed by these trees and their immediate pred- 

 ecessors, have come and gone all the great nations of 

 antiquity. Here are the relics of the Assyrian, the Uab- 

 ylonian, the Egyptian, the Phoenician, the Greek, the 

 Roman, the Moslem, but yesterday, as it seems, the Cru- 

 sader, and now the warring Turk and Slav. And each 

 has done, and perhaps to-day is doing, his part to destroy 

 the mountains' noble covering of forest and to add to the 

 desolation wrought by his predecessor. Could the process 

 but be reversed, and the greed of man restrained and 

 protection be given to the reforesting of the region, the 

 Cedars of Lebanon might again become, as in the days of 

 the Psalmist, the glory of the mountains. 



Another Imported Tree Disease 



ANOTHER of the several imported tree diseases, and 

 one recently discovered in this country, is described 

 ^ by Dr. George C. Hedgcock, of the Office of 

 Forest Pathology in the Bureau of Plant Industry, in the 

 current number of Mycologia. Doctor Hedgcock states 

 that the poplars of this country are threatened by a dan- 

 gerous fungous disease which has evidently been im- 

 ported from Europe. This is the European poplar-canker, 

 a disease which attacks the twigs, limbs, and trunks of the 

 black and Lombardy poplars (Populus nigra) and of 

 the Carolina poplars or cottonwoods (Populiis deltoides) , 

 and may be expected to attack other species of poplars 

 and cottonwoods in regions not yet investigated. 



This disease is caused by the fungus Dothicliiza popu- 

 lea. It occurs first in the form of cankers or depressed 

 dead areas in the bark much in the same manner as in case 

 of the blight of chestnut trees, which is, however, caused 

 by a distinctly different fungus. The effect of the fungus 

 on poplar and cottonwood trees is as follows: cankers 

 are formed at the point of attack, spread rapidly and 

 often girdle the twig, limb, or trunk at the point of attack, 

 killing the part above the canker. Trees attacked on the 

 trunk become *' spike topped." The death of limbs and 

 twigs gives the trees a ragged appearance, which spoils 

 their beauty, and later kills them. This is especially the 

 case with black poplars which are frequently planted in 

 rows along boulevards and avenues. 



The European poplar-canker is most severe in its effect 

 on stored and transplanted nursery stock. Trees when 

 in transit, and when heeled in the ground, or freshly trans- 

 planted in the spring, are readily attacked by the fungus 

 and ruined within a very short period of time. This dis- 

 ease is spread by means of spores produced in pycnidia 



or fruiting bodies in the form of small pimples or pustules 

 in the bark of the cankers. From these pustules in spring- 

 time there are exuded small, sticky, cream-colored tendrils 

 which soon change to a tawny olive or even a walnut 

 brown. These tendrils contain millions of spores which 

 spread the disease in various ways. 



The fungus causing European poplar-canker was first 

 found in Troyes, France, and described in 1884. In 1905 

 the first serious outbreak to be noted was reported and the 

 disease described by Ihe French pathologist Delacroix, 

 An outbreak of the disease in Italy was reported in 1907. 

 This disease was first reported in America by a corre- 

 spondent of the Plant Disease Survey in 1915, from Mas- 

 sachusetts and New Hampshire, but the causal fungus 

 was not correctly identified. During the present year the 

 disease was found prevalent in small areas in certain dis- 

 tricts in the following states : New Hampshire, Massa- 

 chusetts, Rhode Island, Connecticut, New Jersey, Penn- 

 sylvania, Delaware, Maryland, Ohio, Nebraska and New 

 Mexico. The centers of infections appear to be in every 

 case either certain nurseries now known to contain dis- 

 eased trees, or points where poplars received from such 

 nurseries have been planted. As this disease was not 

 known in the United States till recently, it is evidently 

 an imported one, and must be dealt with as such, if it is 

 dealt with at all. 



Conservationists may well pause to inquire how long 

 the merry game of importing tree diseases is to continue. 

 The chestnut is gone: the white pine is going: the gypsy 

 moth continues to enlarge its territory. Is the entire im- 

 porting nursery trade worth the damage it has already 

 caused to more substantial interests? 



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