1056 



AMERICAN FORESTRY 



pith. The developing ears are also sometimes hollowed 

 out. As high as 90 per cent of the stalks in a corn 

 field may be infested. Over 200 borers have been found 

 in the stalks growing in one hill of corn. Control is made 

 more difficult by the fact that the borer feeds on a num- 

 ber of other plants, including the stalks of weeds and 

 flowers, and may live over winter in grass roots. 



Many people believe that we have been bringing in 

 plants from abroad for so many years that now we have 

 all of the pests 

 to which plants 

 are heir. This 

 is a mistake, in 

 the opinion of 

 plant physi- 

 cians who are 

 best qualified to 

 know. The Bu- 

 reau of Ento- 

 mology, United 

 States Depart- 

 ment of Agri- 

 culture, has 

 published de- 

 s c r i ptions of 

 over 3,000 dis- 

 tinct insect 

 pests which are 

 likely to be in- 

 troduced into 

 this country 

 and cause ser- 

 ious loss. About 

 half of these 

 are European 

 insects which 

 feed upon for- 

 est and shade 

 trees and the 

 balance infest 

 v a r ious culti- 

 vated crops. 

 Among the im- 

 portant insects 

 which it is 

 hoped to ex- 

 clude from the 

 American con- 

 tinent are the 

 Mediterranean 

 fruit fly, con- 

 sidered by en- 

 tomologists to 

 tike first prize 

 as a destructive fruit pest, and the pink boll worm of 

 cotton, from Mexico, which is capable of making the 

 best efforts of the cotton boll weevil appear puny in 

 comparison. The life stories of some of these pests, as 

 unfolded by years of study pn the P art f patient scien- 



Photograph by W. 



tists, are so amazing as to be classed with fairy stories 

 by those who are little acquainted with the wonders of 

 Nature. White pine blister rust is an instance. This 

 parasitic fungus is native to the Old World, attacking the 

 stone pine and other native five-leaved pines of Europe. 

 When extensive interest in planting forest trees first 

 began to develop about a score of years ago, white pines 

 imported from Germany, France and Holland, brought 

 this disease to the United States, principally in 1908 and 



1909. Curious- 

 ly, the safety of 

 our white pines 

 depends entire- 

 ly on whether 

 we can control 

 the spread of 

 the disease on 

 currant and 

 gooseberry 

 bushes. The 

 fungus cannot 

 go directly 

 from one pine 

 tree to another 

 but first must 

 spend part of 

 its life on cur- 

 rant or goose- 

 berry leaves 

 and in this 

 stage it has the 

 power of 

 spreading 

 rapidly and 

 widely to other 

 currant and 

 gooseber ry 

 bushes. The 

 fungus then 

 develops anoth- 

 er stage by 

 which it is en- 

 abled to pass 

 from the cur- 

 rant or goose- 

 berry bushes 

 back to the 

 pines. If we 

 destroy the cur- 

 rant and goose- 

 berry bushes 

 we prevent the 

 disease from 

 Hence, improbable as it ap- 



5. Carpenter, New York Conservation Commission 

 STRANGLED TO DEATH 

 A native ten year old white pine tree which has been girdled by the white pine blister ml, a fungus 

 of foreign origin first found in America in 1906. The cankered area above the ax is due to t ne kii ling 

 of the bark by the growth of the fungus. The disease has progressed to such an extent that the sap '< s c- 

 ing cut off from the top and the tree is in the last stages of destruction. This disease cannot be transmitted 

 directly from pine to pine but must pass through an intermediate stage on currants or gooseberry ousnes. 

 To prevent white pines from becoming diseased, remove all currant and gooseberry bushes from the vicinity 

 of the trees. 



infecting our white pines 

 pears to the uninitiated, the salvation of these magnifi- 

 cent trees depends to a large degree on whether people 

 are willing to forego the luxury of currant jelly and 

 gooseberry jam. Congress has passed a literacy test 



