40 
BLIGHT TREATMENT 
The diseased area is sunken, and not swollen like the cankers caused 
by New York apple tree canker. The surface of the blight canker is usually 
brown, smooth, and not cracked or checked, although there are concentric 
rings showing the different periods of activity. The freshly-cankered 
tissues near the edges of an active canker are watery. There are never 
little pimples like those on the surface of cankers caused by fungi, although 
sometimes, after the bark has been killed by the blight, a saprophytic 
fungus may gain foothold. A saprophytic fungus is one that lives only on 
dead tissue; it doesn't attack live tissue. A parasite attacks living tissue. 
Remedy. This disease can be controlled', but, because of its nature, 
spraying is of no help. In controlling it, several things should bo taken 
into consideration. Blight is nearly always present in the orchard, and 
will be carried chiefly by insects (it is never blown by wind, although the 
wind may control the flight of the insects), and there is no known means 
of absolutely preventing infection. Three years out of five— depending 
on weather conditions — this infection is apt to cause serious loss in cer- 
tain sections of the country. To control the disease, begin to fight in the 
autumn by inspecting all trees. First, begin at the bottom and examine 
closely the trunk and branches, then go to the top of the tree and work 
down. Remove all diseased limbs, sawing them ofi at least 3 inches back 
from the canker, and cut out all of the cankers with a sharp knife. Cut 
away the bark 1 inch beyond the outline of the canker if the outline is 
distinct; 3 inches if the outline is not distinct. Remove all the diseased 
bark, disinfect all wounds and tools with a solution of corrosive sublimate 
(mercuric chloride — poison). It is very necessary that each wound be 
disinfected thoroughly with the solution. Disinfecting the tools alone is of 
very little help. This solution is made by adding one part of corrosive 
sublimate to a thousand parts of water. When the corrosive sublimate 
solution has dried, paint the large wounds with a coat of white lead and 
raw linseed oil paint. This disinfection must be given careful attention. 
It is also a good plan to go over the orchard a second time in early spring, 
for cankers overlooked in the first inspection. 
A few cankers may be the source of infecting the entire orchard the 
next spring. The regular pruning may be done at this time. Also cut 
down all old, uncared-for apple, pear, quince, hawthorn, and wild crab on 
your place, and then get permission to cut down those on your neighbors' 
land. They are dangerous. If it is not practical to cut them out, keep 
them cleaned. up in the same way you do the trees in the orchard. 
When the petals of the blossoms begin to fall in the spring, go over 
the orchard, thoroughly examining for blighted twigs and cankers which 
may have escaped the wnter inspection. Break off all fruit spurs as soon 
as they show blight; rub oft with the hands from the trunks and limbs all 
young water-sprouts as fast as they start whether they show blight or 
not. However, don't bother fruit spurs, unless thay are diseased. After a 
little experience, it is possible to distinguish a diseased twig before it 
actually wilts and dries up. It is not necessary to disinfect the wounds of 
these small spurs, but the trimmings should be collected in a bag, carried 
by the operator, and burned. Where a fair-sized water-sprout or twig 
has the blight, cut it out with a pruning knife, and disinfect it with cor- 
rosive sublimate solution. 
About a week later go over the orchard a second .time, and continue 
to do so every week. It must be gone over repeatedly and thoroughly 
to be of any benefit. 
Tools. For winter pruning a light single-edge pruning saw is neces- 
sary. If the trees are largo, a carpenters' saw may also be required. For 
clearing out the cankers, use a sharp-hooked, pointed pruning knife. Carry 
the corrosive sublimate solution in a half-gallon bottle or jug. Also have 
a can or pint cup fastened about the workman's waist and in this carry a 
