Report of the State Entomologist. 185 



when a few apple trees became the adjunct of the simple homes of the early settlers, 

 those of our insects to which they offered more desirable food, than that on which they 

 had previously subsisted, were obliged to wing their way often for many miles in 

 search of a tree upon which to deposit their eggs. If birds were then abundant, how 

 few of the insects could safely accomplish such extended flights. But in the apple 

 orchards of the present day — some of them spreading in an almost unbroken mass of 

 foliage over hundreds of acres — our numerous apple insects may find the thrifty root, 

 the vigorous trunk, the succulent twig, the tender bud, the juicy leaf, the fragrant 

 blossom, and the crisp or mellow fruit spread out before them in broad array, as if it 

 were a special offering to insect voracity, or a banquet purposely extending an irresist- 

 ible invitation to the tent-caterpillar, the codling-moth, the canker-worm, the striped- 

 borer, the bark-beetle, the twig-borer, the leaf-aphis, the bark -louse, the root-louse, and 

 every other of our two hundred species of apple insects. Here they may luxuriate as 

 nowhere else. The reauired food is greatly in excess of insect need. Careful cultivation 

 has made it the best of its kind ; appetite is stimulated : development is hastened ; 

 broods are increased in number: individuals are multiplied beyond the conservation of 

 parasitic destruction; facilities of distribution are afforded with hardly a proper 

 exercise of locomotive organs, and when those almost useless members have become 

 aborted, as in the wingless females of the bark-louse {MytUaftpis pomicoi'tieis) and the 

 ca,nker--worms (Anisopteryxvprnata and -1. ;jojne/a>'/a), the interlocking branches afford 

 convenient passage from tree to tree." 



Increase in Plant Diseases. 



The same causes, viz., high culture, enormous production, and massing in large 

 areas, inevitably promote plant diseases. Let me, in passing, simply name a few of 

 these, since they are so intimately connected with insect attack, being often its pre- 

 cursor or its sequence— and then leave them to be discussed by those to whom their 

 study properly belongs. 



Of the more than two hundred species of fungi known to infest the grapevine, special 

 attention has been called within the last few years, to the following, from the serious 

 losses that they have occasioned: The Downy mildew [Peronospora viticola); the 

 Powdery mildew {Uncinula spiralis); the black-rot (.Physaloi'pora Bidwellii); Anthrac- 

 nose (Sphaceloma ampelinuni), a comparatively new grape disease in this country, but 

 one long known in Europe, which attacks the vine, the leaf and the fruit. 



Of other well-known and destructive diseases, are the peach yellows (no satisfactory 

 cause or cure for which has yet been discovered); the peach-leaf curl iExnasciis defor- 

 7nan.s) ; the plum-rot (^Vo?«7ia fritctigena); the black-knot (Plowrigldia morhosa) of the 

 plum and cherry; the plum-leaf fungus ((S^ptoria cerasina), affecting also the cherry and 

 the apricot, and peach slightly, causing often one-half of the leaf to die and fall away in 

 rounded holes, as in examples recently received by me from an orchard in Canada ; the 

 &^\Aer\\s,t(Raste}iapenicillata)\ the apple and pear scab (Fusicladiimi dendriticum and 

 F. pyrinum); the pear-blight, so extensively written of and but lately shown 

 to be caused by the bacteria which has been named Mici'ococcns amylomrus, 

 also infesting the apple and several other fruits; the tomato-rot in green 

 fruit (probably CtorZosiJOj-HHM /u?(i«m); the gooseberry blight; the raspberry rust 

 iCa'oma nitens); and the spot disease or leaf-blight of the strawberry {Eamularia 

 Tnlasnei), The causes and cures of these and of many others associated with them, are 

 deserving, from their great economic importance, of all the study that is being given 

 to them. Valuable results are expected from the establishment about a year ago of a 

 mycological section in the Department of Agriculture at Washington, specially charged 

 with the study of the fungus diseases of plants ; and it was very fitting that this section 

 should have received the cordial indorsement of your society so promptly given it. 



New diseases are being discovered from time to time. A very remarkable one has 

 lately been reported to the State Horticultural Society of California. The writer names 

 it, " Paralysis of Apricot Trees." It had been observed by him in three different cases 



39 



