488 Insect Pests. 



lays about the fourth day after she is hatched. This true egg is 

 olive in colour and it may survive all through the winter. 



A subterranean race only may occur on a vine. 



When this serious pest is known to occur under glass in this 

 country it is best to at once grub up the vine that is attacked and 

 burn it. 



Bisulphide of carbon injected into the soil will kill the root form, 

 but it miist be done very thoroughly, many small injections being 

 made. 



American and Australian stocks are resistant of this disease, and 

 the introduction of the former has done much to lessen the damage 

 caused by this pest in Europe. 



Care should be taken to see that vines are clear before they are 

 planted in this country under glass, especially if they are imported 

 from abroad. Any found to show any symptoms of the root form 

 should at once be burned. 



RED SPIDER. 



{Tetranychns fclarius. Linn.) 



This well-known vine pest also appears on many other plants, but 

 it must not be confused with the Eed Spiders of fruit out of doors 

 (vide Bryobia, etc.). It feeds upon the leaves, usually on the under- 

 sides, and causes tliem to become mottled or marked, and then rusty 

 in colour. Unlike the Bryobia of the gooseberry it spins a dense yet 

 fine network of silk under the leaves, amongst which it lives and 

 breeds. The presence of this fine silken webbing protects it from 

 ordinary contact washes to a considerable extent. The delicate silken 

 threads are passed out through a conical nipple situated underneath 

 near the apex of the body. The threads of the webbing are very 

 delicate, and are not very noticeable even with a lens until numbers 

 become matted together. The delicate strands are guided by the 

 Eed Spider's feet, and are attached to the fine hairs, veins, etc., 

 of the leaf. 



Dry, warm, and sunny weather favours the reproduction of the 

 mite. 



The eggs are almost colourless, and spherical in form. They are 

 deposited irregularly in the webbing and hatch in a few days under 

 favourable circumstauces into little six-legged mites, which gradually 

 grow, moult their skin, and become the eight-legged nymphs and then 

 sexual adults. The legs are all of nearly the same length, and thus 



