The Delta independent., 1913-01-10
RELATION OF PROPER PRUNING
OF ORCHARD TREES TO
THOROUGH SPRAYING.

The necessity for thoroughness in
spraying is recognized by every one
who has had any experience in fight
ing our worst insect pests. Writer'S
On spraying have urged that tho
cughness is one of the most important
factors entering into the spraying
OF eI alton. While such urging is en-
tirely justifiable. l somemtimes feel
that too little has been said about
preparation for thoroughness. rms
is certainly true in the case of many
of our orchards where more time
spent in heavy and intelligent prun-
ing and less in spraying would result
in much more effective work than is
sometimes done. Orchards have been
observed time and again which had
not seen a pruning saw for years
where the growth of the branches
most entirely from the center of the
trees: where the fruit was small ana
poorly colored; where codling moth
may seek retreat and security
for its survival. and yet when the
owner was asked why his fruit was
wormy he would reply that the arsen-
ate of lead that he sprayed with was
not good. Such orchards defy proper
spraying. or at least require so much
spray to do the work well that the
average orchardist would rather grub
up the trees than spend the necessary
money to spray them. While this
statement may be slightly overdrawn
il is not far from the truth. as any
investigator who has studied spraying
problems will have TO admit.
The horticulturist urges regular
and systematic pruning of the orchard
just as emphitically as the entomolo
gist urges thorough spraying. Heavy
pruning of old trees does not usually
become necessary when each seasoI
after planting. moderate. careful
pruning is done II does become nee
essary in extreme cases where earle
pruning has been neglected, and the
time has come when serious pes
infects the orchard. else the spraying
in all probability will be insufficien
TO control this pest.
Many striking examples of this re
lation between pruning and spraying
were observed in orchards where the
leaf-roller has been doing so much
damage of late years. Where trees
have been allowed TO grow TO an alb
normal height and the upper branches
have not been reached with the spray
they have lost a much higher percent
age of their foliage from the attack of
Z the larvae than branches lower down
where spraying could be more easily
done. This same condition has very
often been observed where codling
moth was the pest sprayed for instead
+ of ieaf-roller. 1t must hold true wheI
/ spraying for any pest. whether it feed
I on the bark fruit or foliage. ii it is
at all prevalent
There are orchard trees in Colorad
that offer resistance to Thorough
spraying so great that our high pres
I sure power sprayers sre insufficient
TO overcome it altogether. Before
spraying should be attempted in such
cases the trees should be cut back to
a reasonable height and all the inter
fering and surplus branches should be
taken out. thus making the tree low
enough so that the topmost branches
( may be easily sprayed and the head
open enough so that each branch may
get it's share of the liquid.
Trees that would properly require
/ from 20 to % gallons Of spray for the
I most thorough work could probably
! be well sprayed with ten gallons when
pruned as they should be.
+ The control of we'll established
/ insect pest. is often no easy matter
( Notwithstanding the fact that we may
have acess 10 the improved modern
power spraying machines: the insec
ticide used may be perfectly reliahl
. in controlling the pests we spray Tor
and yet we may fail because of havin
to do our spraying under unfavorable
conditions. In the orchard nothing
can be more unfavorable than tall
brushy, neglected trees.
GEORGE L. WELDON,
Colorado Experiment station, For
Collins, Colorado.