The red turpentine beetle, a pest of conifers in the California region

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Material Information

Title:
The red turpentine beetle, a pest of conifers in the California region
Physical Description:
4, 1 p. : ill. ; 27 cm.
Language:
English
Creator:
DeLeon, Donald
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
U.S. Department of Agriculture, Bureau of Entomology and Plant Quarantine (Washington, D.C )
Place of Publication:
Washington, D.C
Publication Date:

Subjects

Subjects / Keywords:
Red turpentine beetle -- California   ( lcsh )
Conifers -- Diseases and pests -- California   ( lcsh )
Genre:
federal government publication   ( marcgt )
non-fiction   ( marcgt )

Notes

General Note:
Caption title.
General Note:
"E-568."
General Note:
"May 1942."
Statement of Responsibility:
by Donald DeLeon.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030277083
oclc - 779385683
System ID:
AA00023039:00001

Full Text





May 1942 E-568

EIMRTMENT

OAGRICULTURE

EWTOMOLOGY AND
ANT WIMAANTINE



THE RED TURPENTINE BEETLE, A PEST OF CONIFERS IN
THE CALIFORNIA REGION


By Donald DeLeon,
Division of Forest Insect Investigations


What Its Distribution Is

The red turpentine beetle (Dendroctonus valens LeConte) is a native
insect, which occurs throughout the timbered parts of California and the
rest of the United States. Although no+ u-ually a serious pest, it very
commonly attacks conifers growing on summer home sites and in other recrea-
tional areas. It is widespread in the Bay region of California, where it
occasionally kills Monterey pines. It also breeds abundantly in freshly
cut stumps.

What Its Injury Looks Like

Trees attacked by the beetle produce a copious flow of pitch, which
hardens after a short time, forming a large, irregular, reddish-brown mass
around the point at which the beetle entered the tree (figs. 1 and 2). After
several months these masses turn a whitish or yellowish pink and become dry
and crumbly. The beetles prefer to attack rather thick-barked trees and
confine their attacks to the basal area just above and below the ground
level. They sometimes attack exposed roots. Only rarely have they been
known to extend their attacks as high as 12 feet up the trunk of a tree.

What It Looks Like

The adult beetle (fig. 1, a) is reddish, barrel-shaped, and aver-
ages slightly less than three-eighths of an inch in length. The grubs, from
which' the beetles develop, are legless, curved, ivory white, with dark-brown
heads and a brown platelike marking on the back end (fig. 1, c). There is
also a double row of brown spots down each side. There are no prominent
ha.irs on the body. The pupa, which is the resting stage that occurs after
the larvae have become full-grown, is white, somewhat spindle-shaped, and
has rudimentary legs and wing pads showing (fig. 1, d).







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What Kinds of Trees It Attacks

Only conifers are attacked, and, of these, pines are the preferred
hosts. The trees listed below are known to be attacked. The list is arranged
in approximate order of tree preference.

Bay and Coastal Region.-- Monterey pine, knobcone pine, Bishop pine,
and Coulter pine.

Cascade and Sierra Region. -- Ponderosa pine, Jeffrey pine, sugar pine,
lodgepole pine, western white pine, limber pine, foxtail pine, Digger pine,
knobcone pine, weeping spruce, and Engelmann spruce.

Southern California Region.--Jeffrey pine, ponderosa pine, and Coulter
pine.

How It Spreads and How It Works

The young beetles chew their way out through the bark of the trees
in which they have developed and fly to green trees. They attack only green
trees, green stumps, and, rarely, freshly cut logs. The female beetle bores
through the bark to the wood and then excavates a gallery between the wood
and the bark (fig. 2). On each side of her gallery she lays a large number
of eggs in groups of half a dozen or more (fig. 1, b). The eggs hatch after
a period of about 2 weeks, and the young grubs, feeding side by side, mine
out the green tissues under the bark (fig7 2). It takes at least 8 weeks
for the grubs to reach the pupal stage. Just before the pupal stage is reached
the grub makes a separate gallery and constructs a small cell, in which molt-
ing from the grub to the pupal stage and from the pupal stage to the young
adult stage takes place.

Beetles are in flight from March to October, but the main period of
attack occurs in April and May in the Bay region, and from April through
August in the Sierra region. In general there is one generation a year, but
as the female lays eggs over a period of several months, brood in all stages
of development can be found under the bark of infested trees at almost any
time of the year. Records indicate that where the growing season is short,
some beetles require 2 years to develop. In the Bay region, where it is
warmer than in the Sierra region, there appear to be two generations a year.

What It Does to the Tree

The attacks of a few beetles may kill a patch of living tissue, but,
unless the tree has been weakened from other causes, the beetles are usually
unable to establish a brood, and, even if they do, the injury caused by the
feeding will often gradually heal over. Where the attacked tree has been
weakened from some other cause, or where enough beetles attack so that







-3-


their larval galleries overlap, the beetles will kill the tree unless they
are destroyed. A rough estimate based on field observations indicates that
there must be at least five attacks per square foot over the full circum-
ference of the tree for the attack to prove fatal.

What Can Be Done to Destroy It

If there are only a few attacks on a tree or if they are only on
one side, it would be best not to attempt to control the attacking beetles,
as they will almost certainly be unable to establish a brood and will sooner
or later be killed by the pitch in the tree. However, if a great many beetles
attack the complete circumference of a tree at about the same time, they
should be destroyed before they are able to lay any eggs, for if they Co
become well established, it is quite possible that the tree (especially if
it is Monterey pine) will die either from the attacks of the beetles them-
selves or from attacks by other species of beetles attracted to the weakened
tree. Often the beetles are attracted to a tree dying or at least severely
weakened from some other cause. When this is the case, destroying the red
turpentine beetle will not, of course, keep the tree from dying. Two methods
for control are given below.

Method 1. -- A method preferred by many entomologists is that of cut-
ting out the gallery of the beetle (figs. 4A and 4B) with a chisel and then
coating the exposed wood with a pruning paint. This method is quick, effec-
tive, and permanent if the attack is treated before the larvae have had a
chance to grow-very large. When they are about a third grown they have
spread so far that often large areas of bark have to be chiseled away. Care
should be taken to avoid cutting bark away from the edges of the burrow and
thus exposing the live phloem. The wound caused by chiseling off the bark
should be kept as small as possible and still permit reaching the beetles
and their brood.

Method 2. -- A method of control that avoids removal of the bark con-
sists of injecting a chemical into the beetle gallery. A medical syringe
holding about 1 ounce of liquid works very well, but an oil can that will
squirt a stream of liquid with considerable force is equally effective
(fig. 3). Ethylene dichloride, which is noninflammable but is sometimes'
hard to procure, and carbon disulfide, which is easier to get but is highly
inflammable, are the two most effective fumigants. The common fly or insect
spray that is used in houses against flies and mosquitoes is fairly satis-
factory and very easy to procure. It is somewhat more effective if naphtha-
lene flakes in the proportion of 6 teaspoonfuls to a half pint of liquid
are dissolved in the fly spray.

To inject a gallery properly, the bark should be shaved off until
a small length of the main gallery is exposed or an entrance or exit hole
is located. The liquid is squirted in until the gallery will hold no more.
The liquid will gradually spread under the bark, so that after a few minutes






4 -


more can be squirted in. This process should be continued at least five or
six times. The open section is then closed with putty or a pruning paint.
When fly soray is used, care should be taken to make the injection at or
near the top of the gallery, otherwise the liquid will not reach the beetles
at the upper end of the gallery. To be effective, the insecticide must come
in contact with the insects.

Often one overlooks a gallery, or the insecticide fails to reach
the beetles, consequently the process should be repeated on any galleries
that still show sign-, such as fresh boring dust or pitch flow, of active
beetles.


UNITED STATES DEPARTMENT OF AGRICULTURE
OFFICE OF THE SECRETARY
WASHINGTON, D. C.

OFFICIAL BUSINESS


PENALTY FOR PRIVATE USE TO
PAYMENT OF POSTAGE, $300












F IG I SEASONAL DEIPENI T1 tl

SIERRA REGION. TiERE ARE SEVERAL 1 4 :

MUCH MORE DESTRUCTIVE IL CO, FEI A

IF BUT THEY ARE ALL CONSIDERABLY CALLE T F
7r- 1 HIGHER UP ON THE BOLE, AND TMEI LT



COPIOUS FLOW OF PITCH. T.'l E TL

HEALTHY TREE, EXCEPT PERHAPS tONO1TE, NE. A
/ ; ' -. - .... .B Y T H I S B E E T L E I N D I C A T E T H A T T I ,I l



ENED OR I1S DYING FRLM $OME OTHEL ,A


FIG. 1.-LIFE HISTny tr T ,I TLE. IT SLLDOM PAY T,











FIG. 2.-- NOTE THE WAY THE YOUNC LAtAL t

SHEN THE BROOD IS AS FAR ADVANCEr A Y
EG GALLERY
/ DIFFICULT TO TREAT THEM. IH5LIN. AY C

EXPOSE THE BROOD DISFIGURES TEL TREE Tr A P I
ABLE DEGREE. INJECTION OF A L', ID AS AF.,IE'I


THE TEXT IS PROBABLY THE M, T 8iT<
Ii' r/ -LARVAE FEEDING
PITCH TUBE OFTEN DIFFICULT TO REACH ALL THE LA AE 7 F

CHEMICAL OR ITS FUMES,










FIG, 2.-- CLOSE-UP Of ASE Of' 1r STED TREE,















4 14
'- 4











FIG. --EquIPMENT U.ED IN TREATIN INFESTED TREE SHOWING FIG. 4A. FIG. 48.


ONE OF- T E N Ll U D TREA METHOD OF TREATING A RECENTLY INFESTED A A
ONE OF THE LIQUID INSeCTIiES WHICH CAN BE USED, A GOOD OFF TO EXPOSE THE FULL LENGT- OF THE GALLERY ASP T I
TYPE OF CAN FOR INJECTING THE LIqUID, A CHISEL AND AXE POSED PORTIONS ARE COVERED WITH A PUNNG PAINT 10
WHICH ARE THE BEST TOOLS TO USE TO GET AT THE BEETLES WHEN INFECTION. x
THEY HAVE UST RECENTLY ATTACKED, AND PRUNING PAINT WHICH
18 USED TO COVER THE WOOD AFTER THE BARK HAS BEEN CHISEL- I B, RARY
LED AWAY.


~rATF~PLAN~T BOARD-




UNIVERSITY OF FLORIDA
.126 0923II
3 1262 09230 3626


UNITED STATES DEPARTMENT OF AGRICULTURE
OFFICE OF THE SECRETARY
WASHINGTON, D. C.

OFFICIAL BUSINESS


-SdN~ViS NVSGNO8

SONIAVS 3SN3J30
Hol


PENALTY FOR PRIVATE USE TO AVOID
PAYMENT OF POSTAGE, $300


STATE PLAOFT EA2D 3F r oKDA

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