VINE DISEASES. 147 



email whitish or yellowiish maggots — are also fairly active, 

 but they cannot jump. Both feed on the surfaces of the 

 leaves and shoots, sucking out the juices, and causing 

 them to assume a yellowish tinge and die. Not only do 

 they injure the leaves, but also the young shoots and 

 flowers. They are especially destructive to the young and 

 tender foliage of vines. As a rule, they never get very 

 numerous in vineries that have a fairly moist atmosphere. 

 Remedies. — Sponging or spraying the foliage with an 

 insecticide, or fumigation with a nicotine preparation on 

 three successive evenings generally proves successful. 



Vine Louse (Phylloxera vastatrix). — This is very inju- 

 rious to the vineyards on the Continent, and has also done 

 a great deal of damage in some places in England, attack- 

 ing both leaves and roots. When the leaves are attacked 

 they have a warty appearance, and the roots become 

 covered with knots. 



PiEMEDiEs. — The only sui'e remedy is to burn the vines 

 and roots, thoroughly clean the house with paraffin emul- 

 sion, and paint all the woodwork; then take all the soil 

 out of the border and make a new one. This disease must 

 be notified to the Board of Agriculture. See Chapter V., 

 Part YII. 



Warts on the Leaves — Warts, when they are ex- 

 tensive, intt?rfere with the functions of the leaves, but 

 slight cases of wartiness are not very harmful. It is fre- 

 quently caused by a check, such as ventilating too freely 

 when the house is very hot, improper removal of foliage, 

 etc. 



B DISEASES. 



Black Rot of Grape Vine (Guignardia Bidwelhi).— 

 This disease is not very common in Britain, but still 

 it is just as well that readers should be acquainted 

 with its life history, and the best way of coping with it. 

 The general appearance produced by the disease is well 



L 2 



