STATE HORTICULTURAL SOCIETY. 171 



the fruit is to be inerustecl by this disgusting parasite that destroys 

 not only its good looks, but, what is more to the point, its market 

 value. 



Its appearance on tlie fruit is, unfortunately, too familiar to 

 need description. It also developes on the leaves and young stems, 

 forming small, brownish, more or less, distorted blotches. The mi- 

 croscopic structure of the fungus is very sim])le. It consists of short, 

 branching, coloress threads within the tissues of the host, which 

 throw up immense numbers of short colored upright branches, which 

 push through the epidermis and bear on their summits the very 

 abundant, brownish, usualh' simple, spindle-shaped conidia or sjjores. 

 It occurs throughout this country from California to the Atlantic 

 Coast, and has long been known ia Europe, but it is still a matter of 

 doubt among botanists whether or not it is specifically distinct from 

 the apple scab fungus. ( FnsiclarUHm (/endrificuDi ). In either event 

 they are so nearly alike that, for practical purposes, they may be 

 considered as identical. It is undoubtedly affected by climatic con- 

 ditions, as it is much worse in some seasons than in others, yet it is 

 able to exist where ever pear trees can be grown, and methods of 

 culture seem to effect it but little. Many remedies have been pro- 

 posed, but, so far as known, none have been demonstrated to have 

 practical value. 



Although the fungus is abundantly supplied with easily germin- 

 ating spores, the disease usually seems to spread, rather slowly, from 

 one part of the orchard to another, or to adjoining ones; but when 

 once established, it reappears year after year with the greatest per- 

 sistence. It is for this reason that young orchards, especially if 

 somewhat isolated, are more apt to escape injury than older ones in 

 thickly settled communities. 



This fungus, as also the Morthiera of leaf-blight, belongs to the 

 so-called "imperfect fungi." That is, the form with which we are 

 familiar is supposed to be but one stage in the development of the 

 ])lant. and that when its life history is fully known, it will be found 

 to be connected with some more com})lex and highly developed form 

 occurring on the same, or, possibly, on a different host. The impor- 

 tance of knowing the complete life history of plants that are capable 

 of doing such extensive injury, can not be over-estimated, for, until 

 this is known, we can never be sure we are not overlooking some 

 simple and practical means of controlling them. We see here only 

 another instance of the need of thoroughly equipped Experiment 

 Stations, officered by men cai)al)le of carrying on the ilelicate investi- 

 gations necessary for a full understanding of the uumy insiduous 

 diseases by which our crops are injured and our profits wasted. 



