258 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
where a large staff of skilled men are employed, every effort is made to 
keep the trees clean ; but in some of the smaller ones, understaffed (from 
one of which the trees under notice were obtained), time cannot, or is not, 
given to the work. Is not this a grave mistake ? It is comparatively 
easy to keep young trees clean in a nursery, but when an infested tree is 
sent out to be planted among others the pest is quickly spread, and infests 
what may have been previously a clean plantation. I have seen several 
instances where American blight has been introduced with grafts from a 
nursery, and where clay has been used in the grafting, healthy and thriving 
colonies of insects have been found in the following summer. When wax 
is used there is no harbour for them. A good wax can be made with 
equal parts by weight of Burgundy pitch, beeswax, and olive oil. It is best 
used warm. Many insecticides are recommended to get rid of this blight. 
1 
Fi(i. 126.— American Blight in various Stages. (TJie Garden. 
Gishurst compound is quite safe and effective ; so is tobacco water, made 
with one ounce of black shag to two quarts of boiling water. Petroleum 
may be used in winter when the bark is hard, but is dangerous in 
summer. Brush it well into all infested parts with a half- worn-out paint 
brush during the winter months. Follow it up well in the spring and 
summer with the Gishurst or tobacco water, brushing this again carefully 
into every spot where a bit of the woolly-looking stuff is to be seen. 
Fig. 125 shows the same tree after a dressing of " Abol " used at three times 
the strength recommended for green fly, and applied wi'th an " Abol " syringe, 
which forces the liquid into the crevices better than can be done with a 
brush. I have used this preparation, at the strength above given, on 
tender shoots and found it safe and effective. I wish to lay special stress 
on this fact that young trees may be kept clean, but if they grow on for 
fifteen or twenty years with the blight constantly propagating itself, it 
