406 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



successfully resist its attacks. The European vine, however, succumbs in all parts 

 of the world where the insect exists. In all other countries except the Eastern United 

 States the insect is an importation. Hence, while different foreign Governments have 

 found it necessary to enact laws and regulations to prevent its importation and spread, 

 our own Government has felt no necessity for any such regulations, and whatever lias 

 been done to remedy the evil here has been accomplished by individual effort or by 

 local or State action, as in some parts of California. It is true that under a misap- 

 prehension of the real facts some cuttings sent over to this country last spring were 

 held by the New York authorities, and as it is germane to this letter I quote a portion 

 of my reply to the letter of the Secretary of the Treasury upon this case, referred to 

 me by you: 



" The life-history of this interesting insect maybe thus briefly stated: Starting 

 from a stem-mother, it multiplies agamically through an indefinite number of gener- 

 ations, either in galls on the leaf or m cavities or on swellings on the roots. Its spread 

 is naturally slow in the unwinged condition, whether on the surface or beneath the 

 ground. But winged agamic females are produced during the late summer and au- 

 tumn months, and these are the true migrants of the species, and disperse and spread 

 from vineyard to vineyard through the atmosphere. They lay some half-dozen eggs 

 only, in such situations as afford shade and moisture, and from these come only true 

 males and females, which are mouthless, feed not, and are born simply to procreate, 

 the female laying either below or above ground a single and the only directly im- 

 pregnated egg, which has been termed the winter-egg, and which in the spring fol- 

 lowing gives birth to a stem-mother which may either found a colony in a gallon the 

 leaf or upon the root, the latter being the more common habit. 



"The prohibition of other products than grape-vines is based upon the supposed pos- 

 sibility of winged females settling thereon and depositing the few eggs which give 

 birth to true males and females, which produce the winter egg. Now, the experi- 

 ments which I made in 1875 (recorded in the Transactions of the Saint Louis Academy 

 of Sciences, October, 1875), and which were the first recorded of their kind, show that 

 the eggs from the winged females are most often laid in or on the ground near the base 

 of the vine, and that they are so delicate as to require specially favorable conditions of 

 moisture and temperature to enable them to hatch. I do not hesitate to express my 

 conviction that when deposited on anything else than the lower tomentose surface of 

 the living leaf of the grape-vine, where they can receive moisture by endosmosis, or 

 in the crevices or irregularities of earth that receive from dew or other sources a due 

 amount of moisture, they will infallibly perish. But even supposing that these eggs 

 could hatch, and the resulting female should lay the impregnated egg on any other 

 living plant, and that this egg should in due time give birth to the stem-mother, she 

 would inevitably perish without issue for want of suitable food; while to suppose that 

 all these operations could go on upon any other product or substance than living 

 plants or upon the dry parts of plants is to exhibit crass ignorance of the peculiar con- 

 ditions necessary to the perpetuation of the species at these particular stages. With 

 the utmost care in endeavoring to supply the natural conditions, I have failed nine 

 times in ten to obtain the sexual individuals, and still more frequently to get the im- 

 pregnated egg, and such has been the experience of others in Europe. The danger of 

 introducing this insect upon anything else than the grape-vine, where a voyage has to 

 be made in the tropics, is yet more remote, as even supposing the winter egg could 

 be produced, it would prematurely hatch on the voyage. 



" The only way, therefore, in which Phylloxera can be conveyed from one country to 

 another widely separated therefrom, is upon grape-vines. The recommendation to 

 use certain resisting American vines as stocks on which to graft the more susceptible 

 European vines has resulted in an immense traffic between this country and Europe 

 in American cuttings, and nurserymen engaged in this business, however unbiased 

 they may desire to be, naturally lean toward that side of the question which furthers 

 their own interests. The insect may be carried on the roots of the vines during the 

 winter either in the dormant larva state or in the "winter-egg" state, and while 

 later researches here by myself and abroad by others have confirmed my previous ex- 

 perience in this country, published five years ago, as to the rarity of the winter egg on 

 the canes above ground, and the more recent observations would seem to indicate 

 that wherever it is thus found above ground it is produced rather from the gall-in- 

 habiting type than from the more dangerous root-inhabiting type, yet the fact tli $ 

 this winter egg does occur upon almost any part of the plant above ground, and more 

 particularly under the loose bark of the two-year-old cane, renders it quite possible 

 that the insect may be carried upon cuttings in this winter-egg state, and fully just i 

 ties the prohibition of the introduction of such, as well as of rooted plants, from any 

 country where the insect is known to occur. Indeed, considering the rarity of ship- 

 ment of rooted vines, I strongly believe that the insect was originally introduced into 

 Europe from America in the winter-egg state upon cuttings. I would say, therefore, 

 to those countries desirous of defending themselves from the scourge, that all danger 

 is removed when vines and all parts of vines from infested countries are kept out. 



