I 



PI.ANT DISEASES IN I908. 21 



crotch. There are several theories as to why the ice should 

 cause the bark to die. One is, that it acts as a lens and concen- 

 trates the rays of the sun, causing a scalding of the bark. The 

 position of the injured limbs alone would seem to be sufficient 

 to show that this theory is not a good one. It seems more likely 

 that the injury is caused by the softening of the bark by the 

 melted snow or water before freezing, and that after freezing 

 the bark which is, even before this probably tenderer than at 

 any other part, owing to its being most shaded there in summer, 

 is subjected to a severe frost and it and the cambium are both 

 destroyed. One of the best means of preventing crotch injury 

 is to grow trees with as little crotch as possible, training with 

 a central leader." 



Winter Injury oe the White Pine in 1908. 



Coincident with the large amount of winter-killing of fruit 

 trees in Maine there has also appeared a diseased condition of 

 the white pine, particularly of those young trees wdiich are 

 springing up over waste lands and abandoned pastures and 

 which are leading to a natural reforestation of these areas. 

 The matter has received considerable attention from the public 

 and agricultural press of the State. This naturally led to wide- 

 spread and general alarm among owners of such young pine 

 growth, and has influenced many who were contemplating plant- 

 ing of pines on waste lands, to either give up the project or put 

 it off indefinitely. This trouble has been known popularly as 

 "pine blight" and apparently the term has been used to cover 

 every condition of the tree which the observer considered to be 

 abnormal from the normal, yearly death and shedding of the 

 oldest set of needles on the twigs to the troubles herein 

 described. 



The general notion exists that the so-called pine blight is due 

 to some parasitic agency, although the cause attributed is as 

 varied as the number of writers on the subject. Fungi, various 

 insects, gases from the sulphite mills, etc., are some of the 

 causes assigned by dift'erent individuals in articles, correspond- 

 ence or in conversation. 



There appeared to be a lack of definite information on the 

 subject, based upon careful observation of the trees in the field 



