46 VINES 
The red spider is rarely present in the green- 
house unless the atmosphere becomes drier than 
it should be for the good of the plant. Obviously, 
the preventive measure is occasional spraying. 
A syringing of the plants will also remove this 
insect, except in very severe infestations. 
Caterpillars, the larve of many sorts of beetle 
and moth, rarely trouble indoor plants. On 
vines, even outdoors, they are rarely very serious. 
The Dutchman’s pipe (Aristolochia macrophylla) 
is occasionally attacked, but it is rarely necessary 
to discolour the foliage by spraying, for any 
insects that bother this vine are liable to be so 
large and in such small numbers that they can be 
picked off without trouble. When spraying is 
not undesirable, the best material to use against 
the chewing insects is arsenate of lead in the 
proportion of one pound to ten to twenty gallons 
of water. A fairly weak mixture is desirable on 
many vines, although on the tomato, the potato 
beetle requires a strong dose. Paris green is 
another form of arsenical poison, but slightly 
less efficient and more easily washed from the 
foliage by rain. This, too, is used in various 
degrees of strength, but always add one pound 
of lime for every pound of the poison. Either 
vf these poisons can be added to Bordeaux 
