66 Insects. 



BUSHBERG CATALOGUE. 



rinjlloxera. 



The annexed ligiire (86) s^hows the abnormal 

 swelling of the rootlets which follows the punc- 

 ture of the root-louse; they eventuullj^ rot, and 

 the lice forsake them and betake themselves to 

 fresh ones. As these decompose, the lice congre- 

 gate on the larger parts beyond, until at last the 

 root-system literally wastes away. 



During the lirst year of attack there are scarcely 

 any outward manifestations of disease; only the 

 second and third year — when the fibrous roots 

 have vanished, and the lice not only prevent the 

 formation of new ones, but settle on the larger 

 roots, which also eventually become disorganized 

 and rot — do the outward symptoms of the disease 

 become manifest in a sickly, yellowish appear- 

 ance of the leaf, and a reduced growth of cane; 

 and the vine dies. When the vine is about dying, 

 it is generally impossible to discover the cause of 

 the death, the lice having previously left for fresh 

 pasturage. 



As is frequently the case with injurious insects, 

 the Phylloxera shows a preference for and thrives 

 best on certain species, and even discriminates 

 between varieties, or what amounts to the same 

 thing, practically, some species, or varieties, re- 

 sist its attacks, and enjoy relative immunity from 

 its injuries. A knowledge of the relative suscep- 

 tibility of different varieties to the attacks and in- 

 juries' of the insect is therefore of paramount 

 importance. 



c7 



Type Kadicicola: «, shows tho licallliy roof, h, one on 

 \vhic)i the lice are woikiii^, repicst'iitiiij; the knots 

 and swellings caused by llieir punctures: r. a root that 

 has been deserted l\y tliem, and wheie the rootlets 

 liave comnKMiced to decay; rf, rf, tl, show how the lice 

 are found on tlie hirtrer roots; e, female pupa, dorsal 

 view; g, winged female, dorsal view. 



Most American varieties, indeed even the most 

 susceptible, resist the insect, provided they are in 

 locations suitable as to soil and climate. 



"VVe see in the general resistibility of our puiely 

 native American vines against the I'hyiloxera. 

 a remarkable verification of that law which Dar- 

 win has so ably established and aphoristically 

 expressed, as "thk s^ruviVAL of the fittei;t.'* 



Prof. Riley, in explaining •' why the insect 

 is more injurious in Europe than here," says: 

 '•There exists a certain harmony between the 

 indigenous fauna and flora of a country : and our 

 native vines are such as. from their inherent 

 peculiarities, have best withstood the attacks of 

 the insect. The European vine, on the contrary^ 

 succumbs more readily, not only because of its 

 more tender and delicate nature, but because it 

 has not been accustomed to the disease — there 

 being, doubtless, a parallel between this case and 

 the well-known fact that diseases and parasites 

 which are comparatively harmless among peoples 

 long accustomed to them, become virulent and 

 often fatal when first introduced among hitlierto 

 uucontaminated peoples. Then the particular 

 natural enemies of the insect which belong to its 

 own class, and which in this countrj' help to keep 

 it within bounds, are lacking in Europe; and it 

 will require some time before the closely allied 

 European predaceous species will prey upon and 

 check it there to the same extent. The Phyl- 

 loxera will, also, all other things being eijiial. 

 have an advantage in those countries where the 

 mildness and shortness of the winter allow an 

 increase in the annual number of its generations. 

 Finally, the differences in soil and in modes of 

 culture have no insignificant bearing on the 

 question in hand. Though Phylloxera, in both 

 types, is found on our wild vines, it is very doubt- 

 ful if such wild vines in a state of nature are ever 

 killed by it. With their far-reaching arms em- 

 bracing shrub and tree, their climbing habit 

 unchecked by the pruner's knife, these vines have 

 a corresponding length and depth of root, which 

 render them less susceptible to injury from an 

 under-ground enemy. Our own method of grow- 

 ing them on trellis approaches more nearly these 

 natural conditions tlian that employed in the 

 ravaged French districts, where the vines aie 

 gro^vn in greater proximity and allowed to trail 

 upon the ground, or are supported to a single 

 stake." 



Again, after speaking of the large numbers of 

 winged females rising from the ground during 

 late summer and fall, he adds: ''The winged 

 migrant Phylloxera is wafted about, and will lay 

 her eggs, or, in other words, deliver herself or 

 her progeny, wherever she happens to settle. If 

 this be upon the grape-vine, well and good — the 

 young live and propagate; if upon other plants, 

 they "perish. We thiis have the spectacle of a 

 species annually wasting itself away to a greater 

 or less extent, just as in the vegetable kingdom 

 most species produce a superabundance of seed, 

 the larger portion of which is destined to perish. 

 Thus in the thickly planted wine districts of 

 France few winged insects would fail to settle 

 where their issue could survive, while in America 

 an immense number annually perish in the large 

 tracts of other vegetation intervening between 

 our vineyards." 



Under the stimulus of a large reward (300,000 

 f ranees; appropriated for the purpose by the 

 French Government, innumerable plans have 

 been proposed and experiments made, but no 

 rcmedii has yet been discovered which gives entire 

 satisfaction, or is applicable to all conditions of 



