110 



THE GARDENER'S ASSISTANT. 



egg-laying female deposits her eggs upon the 

 rods in autumn, and the aphis hatched in spring 

 is flask-shaped, amber-yellow or rusty, and con- 

 stitutes the foundress of a colony. She punctures 

 the under surface of the leaf, causing it to grow 

 over her, forming a globular gall, in which she 

 deposits egg -like bodies in hundreds. When 





Fig. 143.— Vine Louse (Phylloxera vastatrix). 



1. Root galls. 2 and 3. Forms of larva. 4. Winged female 5. Portion 



of diseased leaf. < ; . Enlarged Bection of excrescence on. leaf. 



the foundresses are numerous the leaves become 

 studded all over with galls, but more particularly 

 towards the edges. The young from these galls 

 descend to the ground to continue their exist- 

 ence upon the roots, the younger ones of which 

 appear dusted with yellow grains, or develop 

 small tubercles containing lice, while the older 

 roots lose their cortical covering. The root 

 forms of the insect are smaller than the leaf 

 forms, granulated upon the back, and amber- 

 yellow, with an olive tint towards the head 

 and tail. They lay eggs underground. Later 

 generations become more flask-shaped, and of a 



rusty hue. They hibernate in the soil in a 

 dormant condition, but become more active as 

 the temperature rises in spring. Both in Britain 

 (when they do occur) and upon the Continent, 

 the root forms of this louse are by far the most 

 prevalent, and cause the greatest amount of 

 damage. In July some of the insects pass into 

 the pupa state, rise above ground, and develop 

 wings. There are long and short bodied winged 

 forms. In America they spread far and wide 

 in myriads, infesting fresh vineyards. 



Remedies. — The gall-producing forms on the 

 leaves may easily be kept in check by pulling 

 off the leaves and burning them as soon as they 

 are seen to be infested. The root forms are 

 most to be dreaded in this country. In very 

 bad cases the Vines may be cut down and burnt 

 at once, or previously have the foliage destroyed 

 by burning sulphur in the house. Then the 

 borders may be thoroughly cleared out, soil and 

 all being taken to a distance from the garden. 

 Thoroughly clean every part of the house, fill 

 the borders with fresh soil, and get another 

 stock of Vines to plant. Methods of cure have 

 however, been effected by flooding the borders 

 for twenty -five to thirty consecutive days 

 during autumn or winter. Bisulphide of carbon 

 is very effective, according to several authorities 

 who have employed it. The method is to put 

 2 ozs. of the material into a phial or glass vessel 

 left open at the top and sunk at intervals in 

 the borders, and near the roots of the Vines. 

 The liquid is very volatile but heavy, giving off 

 an offensive odour, which penetrates the soil 

 and kills the insects, but is not injurious to the 

 Vines. The material is poisonous to human life, 

 inflammable, and must neither be spilled nor 

 brought near a fire nor light. Sulpho-carbonate 

 of potassium has also been found efficacious. 

 Another remedy is carbolic acid, mixed at the 

 rate of 1 part to 50 or 100 of water, and poured 

 into holes about 10 inches deep in infested 

 borders. AVhen the Vines are grafted on the 

 roots of varieties of the American Vine, the insect 

 does not increase fast nor do much damage. By 

 adopting some of the above remedies on the 

 first appearance of the attack, gardeners have 

 little to fear, for the louse increases and spreads 

 but slowly, as our climate does not seem very 

 favourable to the production of winged forms. 



Wireworms. — These are the larvae or grubs 



of beetles belonging to different genera, and 



j numbering nearly seventy species, many of 



! which are rare, while others do not feed on 



garden crops. Only four of the commonest 



I affecting fields and gardens need be noted here. 



