^58 



Protection Against Fungi from Abroad. [Oct., 



gardens of Kent, what a field for mischief it would findl The 

 damp climate of England would probably suit it, and the well 

 nourished and well tended Kentish heps would, in all likelihood, 

 furnish the most acceptable of hosts to that type of parasitic 

 fungus. 



Fire Blight. — The growing of susceptible pears in some parts 

 of the United States, notably in southern New York State, is 

 rendered unprofitable by the devastation caused by the Fire 

 Blight, a bacterial disease due to the organism Bacillus amylo- 

 vorus. Dr. H. H. Whetzel, the Professor of Plant Pathology in 

 Cornell University, says " Fire Blight is the most universally 

 destructive of all pomaceous fruit diseases." Dr. C. E. Orton 

 may also be quoted as stating " The losses from Fire Blight run 

 into millions of dollars in certain years in this country." 



This disease occurs on Pears, Apples and Quinces. It is most 

 destructive to young apple trees in the nursery and to older 

 pear trees. There are four prevalent forms : — 



(a) Fire Blight itself, which is a twig blight. The leaves, 

 blackened as if by fire, cling to the blighted -twigs. Sometimes 

 only the apex is black, sometimes the destruction extends two 

 or three feet back. 



(b) Blight Cankers slightly sunken and blackened with a 

 cracked rough edge delineating the morbid from_ the healthy 

 tissue. 



(c) Blossom Blight causes the flowers, dead and brown, to 

 hang on the withered spurs. 



From each there oozes, in wet weather, the sweetish, sticky, 

 brownish-white fluid which bears the millions of bacteria. 



(d) Collar Blight, the canker attacking the trunk of the tree, 

 is particularly common on apples. 



The appearance of the trees reminds one of an intensified 

 attack of Blossom Wilt or Wither-tip, but the leaves are blacker, 

 the flowers more scorched-looking, the effect more severe. A 

 definite ooze is, moreover, usually present as drops on the diseased 

 fruit or welling out from cracks in the twigs and diseased boughs. 



Black Knot. — A disease which, like the Chestnut Blight, has 

 so far never appeared in England, is the striking and unsightly 

 Black Knot of Plum and Cherry (Plowrightia mnrhosa). This 

 abounds on the wild plums and cherries in the United States of 

 America, both on the native plums Cincluding the tall Pied Plums 

 and the straggling Beach Plum a foot or so high) and on the 

 introduced sloe or blackthorn, which is very common along the 

 snake-fences and edges of the roads in New England. Cherries, 



