492 



JOUENAL OF HOKTICULTUKE AND COTTAGE GAEDENEE. 



[ December 19, 1872. 



to be so much the more destructive because the first appear- 

 ances of the evU had perhaps been overlooked. From this 

 time the disease did not cease to spread, and it now rages from 

 the department of la Drome to the confines of la Crau, more 

 particularly on poor, dry, stony, and damp soils. 



The ai'rondissement d'Orange on the left bank of the Ehone, 

 ■which is one of the most severely visited spots, has already 

 lost during last year 3.600 hecatares (8.896 acres) of Vines out 

 of the 10.880 (26.886 acres) which it formerly possessed. The 

 department of Basse Alpes, which has until now escaped, is 

 beginning to be attacked. 



On the right bank of the Ehone the progress of the disease 

 has not been so quick, but the departement du Gard has been 

 affected in a great many quarters ; that of l'Ardeche has in- 

 fected Vines, and l'Herault is already showing the early symp- 

 toms of the evil. The progress of the disease in Bordelais, 

 where it appeared some years ago, has been slower than in the 

 valley of the Ehone. 



Phylloxera vastatrix — Wingless form. 



tained centres of contagion. When the roots of the afflicted 

 Vines are examined it is easy to see that they have become- 

 considerably altered in then' nature, for they are always soft 

 and rotten ; and the tissues surcharged and without any firm- 

 ness, yielding to the pressure of the fingers. 



These severe affections are due to a kind of insect which has 

 been named Phylloxera vastatrix. This insect, which is almost- 

 invisible to the naked eye, takes up its abode in the roots of 

 the Vine, and pricks them with its proboscis in order to extract- 

 the juices they contain. These repeated perforations most likely 

 irritate the tissues and induce hypertrophy. They give rise tc- 

 knots upon the fibres of the roots, which are quite peculiar to 

 the new disease, and form a fundamental distinction between 

 it and all other kinds of affections remarked in the Vine, 

 such as the " pourridie " or " blanquet," a sort of rot pro- 

 duced by subterranean fungi, and the disease "Camargue'" 

 which has already caused the destructions of a large number 

 of Vine plantations. It must at the same time be remarked 

 that the Phylloxera never remain upon the roots which are 

 beginning to decompose, but immediately remove from one de- 

 caying part to another which is as yet untainted. In fact, they 

 are the cause of the rot, always going before it, and never fol- 

 lowing after. 



I ^^ 



Phylloxera vastatrix. 



Until now there is not one of our kinds of Vine which has 

 not been attacked by this disease, but it is reported that there- 

 are some American varieties in the outskirts of Bordeaux, 

 which, although they have been surrounded by infected plants 

 for three years, show as yet no signs of suffering from the new 

 complaint. The insect which thus riots on the Vines belongs to- 

 the genus Phylloxera, and constitutes part of the order of 

 Hemiptera, and more particularly of the sub-order Homoptera, 

 the most commonly known of which are the grasshoppers, the 

 lice, and the cochineal. It forms of itself a small family, 

 which is a sort of connecting link between the lice or aphides- 

 and the cochineal or eoccidea?. 



Phylloxera vastatrix — Wingless form. 



The visible feature most characteristic of the new disease is 

 the existence of a centre of attack in those parts which have 

 been but a short time affected, and which extends itself with- 

 out intermission. The portions of the Vine which are con- 

 tiguous to the tainted part let their leaves fall, and grow 

 yellower and yellower until they are quite dried-up. When 

 the seat of contagion has grown to a sufficient extent, and 

 when the disease is severe enough , instead of one there spring 

 up several centres of attack. From the facts it has been 

 generally remarked that the disease is propagated in two 

 ways — progressively and intermittently. The gradual exten- 

 sion of various centres of attack, of which we have just 

 spoken, shows us the first ; their existence simultaneously 

 at several far isolated points is proof of the second. The 

 occurrence of many instances has taught us that the ' new 

 disease of the Vine makes its way by irregular bounds, often 

 abruptly appearing at great distances from the already ascer- 



Phylloxera vastatrix — Galls. 



According to the recently made investigations, the Phylloxera 

 exists under two different forms — wingless and winged : it is 

 not viviparous, but during the whole season and under both 

 forms it only deposits eggs. We must add that the individuals 

 hitherto observed, and they have not been few, have always 

 been female. The male Phylloxera had not been found either 



