C SOUTH
ank Range
F O R E S T SERVICE
U. S.DEPARTWIENT O F AGRICULTURE
P. 0. BOX 245, BERKELEY, CALIFORNIA 94701
CONTACT TO
Robert L. Lyon
USDA Forest Service
Research Note PSW-249
1971
Absaaet: Thbteen insecticides were tested against Ips
paracoafisus Lanier, and six agahst the western pine
nu~
Lec.). The rankhg of
beetle ( D e n c k s ~ ~ f ~brevicomis
toxikity at LDQO by topical appGcation to I. pamcoY1Jusus was: SD 3450 endosulfm malathion
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hndane
phorate
carbayl
caPzbophenothion =
Ilmidin crotoxyphos dimethoate DDT > ~ i l a n
trichlorfon. The rankkg of toxicity to D. bbrevieomis was: Zectran = dichlonros
Dursban
malathion
pyrethins = Endane. Five compoundsZectran, Dursban, malathion, dichlomos, pyrethrhsshow promise for study as possible alternatives Lo
h d a n e , which is now commonly used for bark beetle
supp1ession.
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Oxford: 145.7~19.92Ips pa~'ldcoa~sus:Lg53-414.12+
145.7x19.92 Dendroctonus brevicomis: 453-414.12.
Reh.ievaE Terms: Ips pabraconfusus; Deadroctonus
brev ico m is; toxicity tests; Zectran; Dursban;
malathion; dichlomos; pyrelhrins; lhdane.
Ips paraconfiasus Lanier, formerly known as Ips
confusus (LeConte),l is one of the most aggressive
bark beetles in California. It does the most damage to
ponderosa pine (Pinus ponderosa Laws.) from sapling
size to 24 inches d.b.h., but attacks all pine species
wi"ln its range.2 I. paraconfusus also attacks the
limbs and tops of larger trees. An infestation is soon
followed by the tree-killing western pine beetle
(Den&octonus bvevicomis keC onte), the most destructive insect to ponderosa pine.2
The toxicity of lindane to bark beetles has been
This insecticide, either pure or as
well e~tablished.~
the active ingredient of benzene hexachloride (BHG),
is now used in California and elsewhere as a bark
spray for suppression of bark beetles or for protection againsMheir attack. Nationwide, ethylene dibromide is the only other insecticide which is also
used for bark beetle s u p p r e s s i ~ n . ~
The dependence on such a small arsenal for bark
beetle suppression poses risks which are compounded
by the current disfavor expressed toward chlorinated
hydrocarbons, such as lindane.
As part of a large-scale study to find alternatives to
chlorinated hydrocarbons, we tested 13 insecticides
against Ips paraconfusus Lanier and 6 against the
weskrn pine beetle. The results sugges"chat five of
the chemicals tested-Zectran, Dursban, malathion,
dichlorvos, pyrethrins-show promise as possible alternatives to lindane. Further research and field
testing would be necessary before the most suitable
candidate insecticide is decided on.
MATERIAU AND METHODS
The insecticides tested were formulated in acetone
on the basis of the active ingredient in the technical
grade product. Fresh solutions were made on each
day of testing. Common and proprietary names and
chemical definitions used in this report are those
given by the Committee on Insecticide Terminology,
Entomological Society of A m e r i ~ a .The
~ insecticide
lindane able 2). On the basis of average insect
SD 3450 is not cited. Its chemical name is:
mortalities, tlre ranking of toxicity was Zectran =
5 ,$,7,8,9,9-hexachloro-l,4,4a,5,8,8a-hexahydrodichlowos > Dursban > malathion >- pyrethrins =
1,4:S,8-dimethanophthalazine.
lindane.
Testing procedures were similar to those described
Table 2-Mort~lity of westerr2 pine beetle adults treated with
by L ~ y o n Acetone
. ~ ~ ~ solutions were applied topically
six insectkides at three dosage levels
to the venter of the adult beetle at the rate of I 6-11/10
I ~ o & a ~attdosage
~ l of
mg. body weigl-ft. The insects were held after treatment singly in size No. 000 gelatin capsules. Dead
Insecticide
insects were counted 3 days later.
Percent The insecticides were tested on 6. pavaconfusus at
four to six different concenkrations and replicated
110
100
100
100
Zectran
60
100
aoo
Dichlorvos
usually two t o five times. Full dosage-mortality
96
100
31 00
110
Dursban
regression curves were obtained for tlvs insect by
85
100
100
110
Malathion
using a computer program of probit a n a l y ~ i s .Addi~
100
53
100
110
hrethrins
"conal candidate insecticides were tested at three
62
95
100
180
Lindane
concentration levels agkst the western pine beetle.
RESULTS
At ED,, , three insecticides-SD 3450, endosulfan,
and malathon-were more toxic "clan lindane to I.
paraconfusus, though the differences were not large
(tabk I; fig. I). Malathion was less toxic at the LD,,
level.
All six insecticides tested on the western pine
beetle were as toxic as or sEghtly more toxic than
Table 1- abxicihy of 13 insecticides applied t o p k d l y to Ips
~amconfususadults
I Number
&. /g body weight
SD 3450
Endosulfan
Mdathion
Llindane
(standard)
Phorate
Cabsyl
Cabophenothion
Imihn
Crotoxyphos
Dimethoate
DDT
Di?lan
'Ifrichlorfon
~
L = dose
D lethal
~
~to 50 percent of sample; LDgO= dose lethal
to 9 percent of sample.
2~oxicityrelative to findane:
LDS0
lindane
= toxicity index.
LD50 (,,
candidate
l~orrected for natural moaality by Abbott's formula;
natural mortaEi;y from treatment with acetone alone was 14
percent.
T h e five c o m p o u n d s - Z e c t r a n ,
Dursban,
malatl~on,dichlorvos, and pyrethrhs-appear to be
the most promising candidates for further study,
'Ifl~ey are at least as toxic as lindane and, unlike
chlorinated hydrocarbons, do not have the "eoublesome quality of persistence in the environment. They
may, however, have insufficient persistence in bark.
Residual action in bark is of considerable importance
in bark beetle suppression, as it tends to increase the
effectiveness of sprays and their flexibility of use.
Residual life of these five compounds, when applied
to bark, is not now known. Laboratory and field tests
with deposits in bark are needed "I assess fully their
potential for use agakst bark beetles.
,
NOTES
'kanier, 6. N. Biosystematics o f North Arrzerican Ips
(Coleoptera: Scolyt id@ Hoppirzg9sgfoup IX.Can. Entomol.
102(9): 1139-1163, 1970.
2~truble, George R., and Hall, Ralph C. The California
five-spined engraver-its biology avzd eo~ztml.U.S. Dep. Agr.
Ckc. 964, 21 p., illus. 1955.
3 ~ y o n ,Robert L. Structure and toxicity of insecticide
deposits for contml o f bark beetles. U.S. Dep. Agr. Tech.
Bull. 1343, 59 p. 1965.
on,
Robert L. Formulation and s2.Yucture of residual
insecticides for bark beetle cont'rol. In, Advances in Chemistry Ser. 86: 192-206. R. B;. Gould, ed., Washington, D.C.:
Amer. Chem. Soc.1949.
'~illings, Samuel C. Consolidated list o f approwd conzmorz
names of insecticides and c e r t ~ i nother pesticL"des. Bull.
Dosage ( p . g . 4 . body weight)
Figure 1-Dosage-mortality curves f i r 13 insecticides upplied topical&
to Ips pamconfusus adults.
Entomol. Soc. Amer. 1143): 204-213, 1945; 1243): 356-35'7,
1966; 1344): 342, 1967; 14(4): 289, 1968; 1564): 380, 1969.
he assistance of Burton B. Combs and Peter Letchworth in
the bioassay is gratefully acknowledged.
?Ly on, Robert L. Toxicity of severa.rak residual-type insect;
cides is selected western bark beetles. J . Econ. Entomol.
5262): 323-327, 1959.
8&ovided by Gerald S. Walkon, U.S.Forest Service, Upper
Daby, Pa.
The Author
ROBERT L, LYON, a research entomologist, is responsible for insect
culture and bioassay in the Station's studies in the evaluation of chemical
insecticides. He attended New Y ark State University College of Forestry,
where he earned B.S. (1953) and M.S. (1954) degrees. He received a
doctorate in entomology (1961) from the University of CaEfornia,
Berkeley.
This pUbGciltion reports $esearch involving psticides. It does not c o n t ~ n
recommendations for their use,nos; does it imply that the uses discussed here have
uses of pesticides must be ne@stered by appropiate State
been regjstered,
andlor Federal agencies before they can be recommended.
:
I
CAWION: Pesticides c m be injurious to Zlumkuas, domestic animals, deskable
plants, and fish or other wildl8e-if they ase not handled or applied properly. Use
a11 pesticides selectively and ca~enTuiHy,Follow recommended practices for the
$ i s p o d of surplus pesticides and pesticide containers.
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ent of Agdcdme
The Forest Semice of the U.S, Dep
. . . Conducts forest and range research at more than 75 locations from Puerto Rim to
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'
The Pacific Southwest Forest and Rmge Experiment StaGon
represents the research brrmch of the Forest Service in Cdifomia and Hawaii.