How to fight the chinch bug


Material Information

How to fight the chinch bug
Series Title:
Farmers' bulletin / United States Department of Agriculture ;
Physical Description:
22 p. : ill. ; 23 cm.
Packard, C. M ( Clyde Monroe )
Benton, Curtis, 1898-
U.S. Dept. of Agriculture
Place of Publication:
Washington, D.C
Publication Date:


Subjects / Keywords:
Chinch-bugs   ( lcsh )
Chinch-bugs -- Control   ( lcsh )
federal government publication   ( marcgt )
non-fiction   ( marcgt )


Additional Physical Form:
Also available in electronic format.
Statement of Responsibility:
by C.M. Packard and Curtis Benton.
General Note:
Contribution from Bureau of Entomology and Plant Quarantine.
General Note:
Supersedes Farmers' bulletin no. 1498, The chinch bug and how to fight it, by W.P. Flint.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029641878
oclc - 12221462
lccn - agr37000627
lcc - S21 .A6 no.1780
ddc - 630.6173 s
System ID:

Full Text

I No. 1780


NO. 1780;
o AGR'';

T HE CHINCH BUG is one of the most destructive
native pests of grain and grass crops in the United
States. The worst outbreaks occur in the great grain-
raising region extending from Ohio to Oklahoma,
Kansas, and Nebraska, but heavy losses also occur in
the eastern and southeastern sections of the country.
As far as is known, this insect feeds only on plants
belonging to the grass family.
The chinch bug has two generations a year, and
three in the extreme southern portion of its range.
When full grown it is black with white markings, and
is about one-sixth of an inch long.
The few natural enemies of this insect are not suffi-
cient to prevent it from injuring crops, and spraying
and dusting are too expensive to be recommended
for general use.
The chinch bug can be fought most effectively (1)
by growing immune or resistant crops or crop mix-
tures, (2) by modifying farm practices to prevent
infestation, and (3) by the use of barrier traps to kill
the bugs while they are migrating from small grains
to corn or other susceptible crops.
This bulletin supersedes Farmers' Bulletin 1498,
The Chinch Bug and How to Fight It.

Washington, D. Issued August 1987



By C. M. PACKARD, senior entomologist, and CURTIS BENTON, junior entomologist,
Division of Cereal and Forage Insect Investigations, Bureau of Entomology
and Plant Quarantine

Page Page
Occurrence and importance ..---------------- Plants attacked --.-----------------....----- 7
What the chinch bug looks like-------------- 2 Plants not injured .___...----------------.---
Seasonal history --------------------------- 2 Importance of weather in chinch bug abun-
How and where chinch bugs pass the dance.....----------------.._--------.--- 8
winter-, _-.-------------------------- 2 Natural enemies--------------........-.... 9
The spring flight ..---.--------------. 3 Control measures --------.. -------------- 9
Development and migration of first gener- Growing immune or resistant crops------ 10
ation.---- .-------------------.------. 4 Modifying farm practices to reduce infes-
The summer flight and development of tation ........ ------------.....-------- 11
later generations ----------------------- 5 Barriers ....-----------.. .-_ _-- .. 13
The fall flight to winter quarters ---.----- 5 Spraying and dusting with insecticides as
Life stages------... ...----...-- ------------ 5 emergency measures--...--........-.... 20


T HE CHINCH BUG is one of the most destructive of the native
insects attacking grain and grass crops in the United States.
It is of some importance in the southeastern and eastern sections of
the country, but has reached its greatest abundance in the regions
drained by the Mississippi, Ohio, and Missouri Rivers.
A knowledge of the best methods of controlling this insect has been
sought by grain growers since its first general outbreak, which oc-
curred about 1785. During the intervening 150 years there have
been numerous chinch bug outbreaks, in some instances covering only
parts of one or two States, but in others extending over a much
wider area. The chinch bug's habit of feeding on the widely grown
grains and grasses, its rapid rate of reproduction under favorable
conditions, and its frequent occurrence in enorimous numb1ers 1make
it an extremely difficult pest to fighrt. The general use of insecticidal
sprays is impractial, becrase chinch ugs fd by sucking the plant
juices, and only 1 iso)010 that kill by actual contact witll the insect
areP efective. Other means of combat ing then must t erefore be

1 cknowledgient is due to W. P. Flint, '; I. TI. Dlunan, and J. II. Bi fr for informa-
tion taken from Illinois Agrisultural Experiment Station C'ircular 4:i1; to C. 1. i)rlnkl
G. C. Dicker, and A. D. Worthinton for information and figs. ti anmd 1( takenl front Iowa
Agricultural Extension Service (irculnar 21;1; and to Halph 0. Snelling for oh'servtioir
on t th third generaton in Oklaloma (Jour. Econ. Ent. 2j7: 77 -i, illui. 13I. The
photograph reproduced on the title lage is used by courtesy of 3.1. 1. Ialis, of the Itdiana
Agricultural Experinent Station, and the photograph used for fig,. 7 wa made by M. l.,
Farrar, of the Illinois Natural HIistory Survey. Material froAm I'armcrs"' Bullehtin 148,
The Chinch Bug and flow to Fight It, has been freely us'dl.



The full-grown chinch bug (Blissus leucopters Say) is a black
insect with white markings, not over one-sixth of an inch long (figs.
1 and 5, 0). Both long-winged and short-winged fors are found,
but the long-winged form prevails throughout the Central States.
It is capable of flying considerable distances, probably as far as 10
miles in a single flight when the wind is favorable. The short-
winged individuals are unable to fly. In the East and North a some-
what more hairy species (Bli~ru hirtus Montd.) also occurs, espe-
cially in lawns and grassy areas. Short-winged individuals are usu-
ally more prevalent in that species.

FI.uiE 1.-Chinch bugs, twice natural size.

Ordinarily there are two generations of the chinch bug each year
throughout its entire range in this country, with a third eneration
in the extreme South, and occasionally a partial third generation
farthier north.
Chinch bugs pass the winter in the adult stage, hidden away in
shelters that afford them good lprotection from the weather. They
prefer to hide dee) down in thie tufts of the clump-forming native
grasses (fig. 2). These grasses are known locally as bunch grass,
bluestem, prairie grass, broomigrass, swale grass, eardgrass, and by
se eral othler names. The bugs also hibernate in clump-form
grasses, such as timnothy, purpletop, orchard grass, dropseed, and
sedges, especially where, the so-called bunch grasses do not occur.
Manly h~tgs s ps the winter under leaves and litter in the borders of
woodlantids and mter hedg es. Leaves or litter containiing some grass
(fig. 3) are 1referr'ed to either of these materials alone. From No-
\:vemnb to April the moslikely phlaces to) find chinch bugs are the
Stypes of cover j1ust described, especially o11 Warm southern and
esternl'l exl)os(ures Where the su1n sho81ne (1during t1e afternoflons of tfwe
p)'rece( ing Sipll)t embr and October w henl t111ey erel seekillng winter
quarl er s.
hinc bugs may soltilmes be f)ounlld und er th leaives of 11111eiln
or ofter weeds t at f iorl rosettes of large lea1ves at the surface of
tI1 ground., under tle bark of dead trees and fence posts, under


boards and logs, in shocks of corn or standing cornstalks, in sor-
ghum stubble, or under the loose boards and shingles of houses, in
shds and outbuildings, and in various other shelters. The percent-
age passing the winter in all such places, however. is small, and many
of the bugs die.

FIGCRa 2.-Bunehy perennial grass like this are preferrd by chich h bus for winter

The spring flights of overwintering bugs occur some time bet wet
Febrlar or March and the last part of May, depelding 1on the sea-
son, on sunnIy (das when for several hours the telli)erature remins
at 70 F. or more, and usually only after 1 or 2 such days. In most
years the flight is gradual but sometimes nearly all the chinch bugs
in a locality leave their winter shelters during 2 or 3 dlays of favor-


able weather. They usually settle in fields of small grain, especially
in the thinner or poorer stands. The greater numbr of the bugs
locate in wheat where that is the predominating small-grain crop,
but they may often be found more abundant in rye or barley where
these grains are growing. In certain years, when oats have been
plantedl early and cool weather has delayed the flight until the oats
have made a good growth, many of the bugs may also setle in this
crop. In such years a few of them may even fly direct to young corn.
Once in the fields of small grain, the bugs spend a few days feed-
ing and mating before egg laying begins. Ordinarily little or no
injury to the small grains is apparent as a result of thir feeding,
but in years of drought and heavy infestation they may seriouslr
injure or even kill the small grains in which they settle. When con
ditions become unfavorable for them, either through the drying up

FIFcnE 3:.-Tufts of grass among woodland leaves are also favored places for hibernation.
of these grains or because of thick rank growth they oten move to
other fields or portions of fields more to their taste Occasionally
serious infestations of oats and corn occur in this way. Tere is
often a considerable flight of the old bugs from the small rains to
young corn after they have practically finished laying egs. he
suldden appearance of these spent adults in the cornfields is alarm-
ing, but needlessly so, since they soon die without doing much feed-
ing or egg laying on the corn. The real danger at this time is from
the young bugs they left behind thea in the small grains.
After the period of feeding and nmting, the feales begin to lay
their eggs. Thes e ae deposited behind the lower leaf sheaths of the
ra'a plants 1or in the ground around th(e plants, and in dry years
wlen the ground is cracked they nay be laid on the roots. The
eas or(linarily hiatch Il froml 1 to 2 weeks. By wheat-harvest. time
t he old bugs are r'acticly all l (ead, and the young blgs of the new

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FIMUmI 4.-Seasonal history of the ehinch bug In the Central States. 40614'--11 (Facep.4)


generation are present in nearly all stages of growth, although still
unable to fly. As the small grains ripen or dry up, the young bugs
begin traveling on foot to find succulent food. They do this mainly
in the afternoons of sunny days, although in cloudy weather there
may be some movement throughout the day. At this time they move
into adjacent fields of young corn, sorghum, or other plants of the
grass family, where they resume feeding and complete their growth
to the winged stage. It is during this migration that barrier-trap
control (see p. 13) is effective.
From 2 weeks to a month after the small grain is harvested there
is a second flight to seek favorable host plants on which to feed and
deposit eggs. It is during this flight that the bugs spread throughout
the corn and sorghum fields, especially to thin stands or poor growth.
As the summer advances, the adults of the first generation complete
their egg laying and gradually die off, while the second generation
hatches from these eggs and feeds mainly on corn, sorghum, foxtail,
timothy, Sudan grass, and certain other grasses which may be in
succulent condition during the summer. The second generation
reaches the full-grown winged stage late in the summer or early
in the fall. In the extreme South, where activity begins earlier in
the spring and continues later in the fall, a third generation usually
develops. Under particularly favorable conditions a partial third
generation sometimes occurs as far north as Iowa.
The third, and last, flight occurs in the fall, when the adults of
the second and third generations leave their summer food plants and
seek hibernation quarters. Much of this flight seems to be rather
gradual, beginning late in August and continuing through October
and, in the South. even into November. General flights often occur,
however, during the latter part of this period, particularly on very
warm, sunny days following a period of frosty weather. The bugs
seek winter (uarters only on days when the sun is shining and while
the temperature is at least 70 F.
Once in theirr winterquarters they became sluggish when the air
temperature is low, and inactive when it is below freezing, but
during periods of comparatively high tempnerature in the winter they
may move about to a limited extent. Although they may take water,
they apparently do not feed from the time they seek their winter
quarters in the fall until they leave them in the spring. Some mating
ay before the spring flight. The seasonal history of this insect
is summarized graphically in figure 4.
he female chinch bug lays several hundred eggs at the rate of
15 or 20 a day; hence from 3 to 4 weeks may be required for her
to lay her full quota. The eggs, which are about one thirty-second
of an inch long (fig. 5, A), hatch in from 7 to 45 lays, depending
mainly upon the tenmperature. A very young bug (fig. 5, I) is about


/ C
F &

li a ..u 5,.'Th4e rhilnch hug: A, I ggs; 1B4, the fie lmlinature stagess (, the winged adult.
All greally enlarged.


half the size of a pin head, and bright red marked with a transverse
band of white. In the course of its growth its skin is shed five times,
and each change gives it a darker coat until, in the last stage before
acquiring wings, it has lost most of its red color and become grayish
black with a conspicuous white spot on the back between the wing
pads. In all these preliminary stages (fig. 5, B-F) the insect is
wingless and has to depend entirely upon its legs for locomotion. In
the sixth, or adult, stage the insect has wings, is about one-sixth of
an inch long, and is black with white markings (fig. 5, G).
So far as is known, the chinch bug feeds only on plants belong-
ing to the grass family. This includes all our small grains, corn,
broomcorn, the sorghums, millet, Sudan grass, and other wild and
cultivated grasses. Of the small grains, barley seems to be pre-
ferred above all others. It has been observed repeatedly that, where
several kinds of small grains in practically the same stage of devel-
opment are available to the bugs in the spring, barley is by far the
most heavily infested. Barley, spring wheat, winter wheat, rye,
and oats seem to be attacked in about the order named, although this
order varies from year to year with the condition of the grains at
the time of the spring flight. Where any one of these grains pre-
dominates, the chinch bugs readily feed upon it. During April, May,
and June, after the spring flight, probably 90 percent of the bugs
are found in the fields of small grains. Where the acreage of small
grains is relatively low, the, bugs may be found on timothy, june-
grass and several other wild grasses that appear during these
months. Occasionally a few bugs occur on bluegrass, but apparently
this grass is not succulent enough to be attractive, as the chinch bug
feeds only by sucking, and it must have a food plant with a consid-
erable flow of sap, as well as with stems that it can pierce readily
with its beak.
Throughout the corn-growing sections the second generation of
chinch bugs depends mainly upon corn for food (fig. 6), although it
also feeds on other grains and grasses that may be in succulent con-
dition late in the su1mmer, including timothy, barnyard grass, tickle
grass, crabgrass, foxtail, and bent and other lawn grasses.
Fortunately, the chilnch bu does not develop on 1any memlber of
the great family of soil-uilding crops known as legumes. Th
clovers, alfalfa, vetch, lespedeza, soybeans, cowpeas, field peas. pal-
nuts, and velvetbans are all immune from chicl-bug injury. (Other
common crops not belonging to the grass family that may be grown
during periods of chinch-bug abundance with the assurance that the
will not be damaged are sunbflower, flax, rape. stock eet, buck-
wheatm, pu)Ipkin, squasih anid all the truck or garden crops except
sweet corn. Wlenl th btgs are extremely abundant a nd their nor-
m1al food plants become vePry scarce t11trough the comlbied result of
Ilteir ravages and d oulgh1t, th ley sometimes Iry to feed on legumes a
certailn vegetable crps. Tley canot fee( successfully on these
plants, however, and only rarely do they attempt to do so in 1nulwTrs
4 14a-41----2


large enough to cause any injury The substitution of legumes ad
other immune crops for small grains and corn offers one of the mast
important and valuable way. of av'oiding or overcoming trouble due
to chinch bugS..

The weather is the chief factor governing the abundance of chinch
bugs. They are most susceptible to weather conditions while they
are hatching. hatchi. T tcing period of the first generation extends
from April to about the middle of June, and that of the second gen-
eration from the middle of July to the middle of September, with

Fir;ri 0.-Corn damaged by invasion of chinch bugs from adjacent small grain. This
couldl have been lrevelnted by timely use of a good barrier or by not planting corn and
small grain in adjoining lields.
sonle variation according to the latitude. Frequent heavy, driving
Iainls (during these period s beat tle young lbugs into the nud, froml
which they are uinable to esca e. Such storlms also cover the eggs
with mulld and prevent theml from hatching, and keep the females
fro laying their full llnuber of eggs. As a result the bugs may
be of little illportance as farm pests for several seasons. Frequent
raills or periodl, s of warm, d(llml weather also favor the development
of t le chllnch bugs'r worst 111tulral lenemy, the white-fungus ldisease.
(llhicll hbug are less able to survive an open, wet winter than a
cold one with heavy snow covler. Many bugs re also killed by sudden
chllIges 11l temll)eraturile, extlr elr lowt tevmlleratulres lhile ther is
little islow cover, or the folrllatitml of ice in thelr hilbernation (iar-
ters dlue to a sidden feze ollowing1 a thaw or rain. In the Middle
"West, h, oevelss thla 1() l)elcent of thed bugs die in a normal
All tih rec(orded outbreks of the chinch bug have begun during
periods of normal or less tl:a normal rainfali, and it has usually


been several years before adverse weather and other natural condi-
tions were able to reduce the number of bugs to the point where they
became unimportant. One of the most persistent outbreaks orig-
inated in 1910 in Illinois, Missouri, and Kansas, and, except in 1915,
when an extremely wet summer greatly reduced their number, losses
occurred every year until 1925. Again in 1930 lack of rainfall dur-
ing the breeding season allowed increases in chinch bug abundance
which culminated in 1934 in the most severe and widespread out-
break ever known. Populations were greatly reduced in 1935, lo-
cally by winter mortality but mainly by the widespread cold. rainy
weather in May and June, which delayed the spring flight, reduced
egg laying, and destroyed many bugs of the first generation as they
hatched. Shortage of rainfall, however, during the remainder of the
season, and again in 1936, favored chinch bug increase, until at the
end of 1936 threatening numbers were again present in several Mid-
western States.

Probably the most destructive natural enemy of the chinch bug is
the white-fungus disease (Beauveria globulifera). It is generally
present in the fields throughout the country, but its effectiveness is
dependent on the weather. Since it has been proved that the spores
of this fungus are present wherever the bugs are common, its artifi-
cial dissemination as a control measure is needless.
Next in importance is a tiny wasplike parasitic insect. (Eumicro-
soma benefica Gahan). This little wasp lays an egg in the chinch
bug egg. The maggot hatching from the wasp egg consumes the
contents and develops inside the chinch bug egg, and when this
maggot becomes full grown it changes to the adult wasp, which
emerges from that egg instead of a chinch bug. This beneficial
insect is so small that it is probably never seen by farmers. When
held in the palm of the hand, it appears to be merely a dark speck.
and only microscopic examination reveals it as an insect; yet rec-
ords show that it has parasitized from 30 to 50 percent of the chinch
bug eggs in certain localities. Such a high percentage of parasiti-
zation is unusual, however. It is known to occur over most of the
States of the Middle West and in one Eastern State, but has not
been taken in the far West.
Several other fungus diseases and insects also attack the chinch
bug; and a number of birds, including the bobwhite, the red-winged
blackbird, the catbird, tlhe brown tlhrasher, and the leadowlark, are
known to feed on it. More than 2(00 chinch bgs were found ill the
stomach of a single brown thrlasher and more than 100 each in th
Stomachs of a bobwhite ahd a meadowlark. Many other birds have
taken from 5 to 50 chinch bugs at a single meal. None of these.
however, appear to be important factors in its control more than to
aid other natural enemies in preventing serous outbreaks.
There is so much uncertainty about the duration of chinch bul
oulbreaks that it is ner slfe for tile grain grower to depen(d upon
natural agencies to acurb losses from tiheml. Varlouls Ietlods of con-


trol, including spraying and dusting, have been tried, but there are
only three measures that have proved generally practical. The
following methods can be used effectively under actual farm condi-
tions, as will be explained, and by their use losses due to chinch
bugs can be materially reduced: (1) Growing immune or resistant
crops or crop mixtures, (2) modifying farm practices to prevent
infestation, and (3) using barrier traps to kill the bugs while they
are migrating from small grains to corn or other susceptible crops.
Since the first-generation bugs depend mainly on small rains for
their food, and those of the second generation, feed mostly on corn
and sorghum, a good way to hold this insect in check is to make its
food supply as scarce as possible. This can be done by reducing
the acreage of small grains where corn and sorghum are the leading
crops, and that of corn and sorghum where small grains predomi-
nate, and planting legumes or other immune crops in their place.
In this way one of the generations of bugs will be severely handi-
For a farm especially well adapted to corn production, a rotation
of corn, soybeans, corn, oats, or wheat and clover will result in as
little loss as any that includes both small grain and corn. With this
rotation corn would occupy about 40 percent and the other crops
each about 20 percent of the cropped land each year. In areas
better suited to the production of small grains a rotation may be
used in which wheat or oats, clover, corn, and soybeans each occupies
about 25 percent of the cropped land each year. The most suitable
rotation for any particular farm where the chinch bug is a problem,
however, can best be ascertained from the county agent or State
agricultural experiment station.
Legumes should not only be grown by themselves, but where prac-
tical they may well be planted among small grains and corn. Ap-
parently there is nothing about these crops that is repellent to chinch
bugs, since they will alight upon and crawl over or through them,
and may even try to feed on them when forced to it by extreme
starvation. Legumes are practically inmmune from chinch bug in-
jury, however, and the growing of the clovers, alfalfa, or vetch
allong small grais 1and of soyblleansor cowpeas among corn ofte
helps to produce a condition of shade and dampnless around thel
lower. )art of the grainll plalts tha is lunfavorable to the bugs and
is avoided by thelm.
xpelrimints in growing corl n with ith nd wilthout soybeans or cow-
peas iave sliown that cosiderabtle protection is afforded the cornl
by these leguiles. Iln tlhe plresence of clhinch bug) infestations c)rn
grown with sioybeans or cowpeas has outyielded corn1 grwn witlout
these liegues by from 2 to 15 bushels per acre. The degree of
henefit depends on the number of chinch bugs present, the fertilit of
tlie soil, and the weather. In extremely dry weather, with a heavy
infestation of chinch bugs, the beneficial effect of the leumes may
1)ot 1e great, and possib ly the b lugs lmy destroy all the corn n
thle field. Evenll 111le silic condlitills, wie planted at the rate of
three beans iper hill of corn, the soybeans themselves have yielded
from 10 to 12 bushels per acre. Under nearly all conditions thy


may be expected to make sufficient growth to afford good pasturage
for hogs, sheep, and cattle, and to give at least a partial crop on the
t has been found that certain strains or varieties of corn and
sorghum are decidedly resistant to the attacks of the second-genera-
tion bugs, although they need protection from the first generation.
Certain types of sorghums, however, particularly the milos, Honey
sorgo, and Bishop kafir, are so susceptible to chinch bug injury that
they are not ordinarily grown where chinch bugs are prevalent. In
southern Illinois the corn varieties Black Hawk, Champion White
Pearl (sometimes called Democrat), Golden Beauty, Mohawk, Wad-
dell Utility white dent, and Waddell Utility yellow dent have made
fair yields under heavy infestations which so badly damaged other
varieties grown in the same field that they produced very little grain.
None of these varieties, however, is chinch bug proof. Practically
as many bugs occur on the resistant as on the nonresistant varieties
of corn. As these varieties require a long growing season, they are
not suitable for more northern locations.
In recent years much progress has been made in Illinois, Kansas,
and Oklahoma with the development of hybrid corns and sorghums
distinctly resistant to second-generation chinch bugs. These results
open up the possibility of finding resistant varieties and hybrids
adapted to other regions as well. The best of these hybrids are
much more resistant than the open-pollinated varieties. When seed
of resistant hybrids is available, it should be used in preference to
less resistant varieties. Some hybrids, however, are decidedly sus-
ceptible to chinch bug injury and should be avoided. When seed of
resisant hybrid corn adapted to any particular locality is not avail-
able, it is recommended that the highest .yielding hybrids or open-
pollinated varieties known to be suited to that locality be grown in
)reference to untried resistant corns brought in from somie other
section. For information concerningl t1he bt resistant, vaieties of
0con or sorghum for your locality, consult your county agent or
State experim'ent station.

When it is not practical to ele ee to eli ate o e redle 1i*ateriallyv
the acreage of small grains on farms where the 1iti ch bug is a prob-
lem, it becomes nlcessary to take other measures to reduce in fest a-
tions in fthlese grains.
"The first measure is the selection of the kind to llant, where a
choice can be made. Chinch bugs will feed and breed abundantly
in any of the small grains llder the right conditions; he1nce note
of them can1 be (lepeded ulpon for use as a tralp l iln wviitl 11ite
bugs may be e tively concntrated and dest roved. Tlie comnl1para-
tive attractiveness of thei sill grains \ries wIvh l te conditiinl of
the grains iln different yetrs or areas, blut it is 1usually ill :a)It t he
following order: Barley, prilg what, witntler \wheat, ryI'e,. and :ts.
The planting (of spring barley should especially I, avoIided when
there is a )ros)ect of chinch bug abundance n, wh. lere fealsile,
the other small-grain plantings should be adjusted to reduce the
acreages of wheat and rye and make use of oats instead.

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1 and March 15, may help to reduce their numbers. On the other
hand, in regions where the bunch grasses are uncommon and many
of the bugs hibernate in other types of shelter, winter burning is
not a practical or effective method of control. Woodlands should
never be burned over, because the harm resulting from destruction
of the young growth and wildlife refuges will more than offset the
benefit. The natural bird shelters in unwooded areas also should be
left unburned or, if burned, should be replaced by a few brush piles
or corn shocks. An additional objection to the burning over of
grasslands is that it increases the danger of erosion. Because of the
injury to the stand and the reduction in growth the following sum-
mer, permanent pastures and hayfields should not be burned. The
burning of small-grain stubble and cornstalks is not warranted, be-

FlUri E 7.--Corn at lt left ruined by invasion of chinch I uli s from ;i:j:~eiunt smnlIl glair : ilhat
on the right saved by a creosote barrier. (Illinois State Natural listory Surlvy.)
cause very few buIS winter over successfully in such cover. -.17
things considered, indcerliminafte and wholesaIe bu'ning is lik: ly to
do more harm tian good.
One of the oldest and best methods for controlling chinch h)ugs
is the use, at harvest time, of barriers along which thle young blugs
can be killed as they crawl from the ripening small-grain fields into
corn or into small grains that imly still be green. As chinch bugs are
dependent oi succulent )llants for food, tI ey are comIl)lled to leave
the small grain wlel it ripens and lries or is cut. At tis 1timWe only
a few bugs have reached the full-grown, or winged, sa, ad ost
of them hiave to migrate on foot. By thle timely clnst uctionll aiil
maintenance of barriers it is possble to prevent most of lthe damage
done to corn or previously uninfested small -rai ty the blgs
1pmigrting to it on foot (fig. 7), and alll to retiuce thie lda tia e tl


corn by their progeny later in the summer. The sang of only 1
acre of corn more than repays the cost of 80 rods of barrier. In
one instance 8 bushels of bugs were caught along half a mile of
creosote barrier in a week, and approximately the sme quantity
in the same field the next week. By counts of single quarts of
chinch bugs it was estimated that at least 60 million chinch bugs
were caught along this line in 1 week.
Barriers are not effective in controlling the bugs after they have
acquired wings. In the more southern areas the bugs may be winged
before they leave the small grains, thus rendering the barriers totally

Many kinds of barriers have been tried, and several have been
found effective. Field tests have shown that oils with a fairly light
body are most easily applied, soak into soil or paper readily, and,
unless applied too heavily, do not run down at right angles to the
line and thus reduce the efficiency of the barrier. Heavy oils lose
their effectiveness sooner through loss of odor, hardening, or drying,
and becoming covered with dust.
Coal-tar creosote has been used extensively for a number of years,
and this material is the best of any thus far tested. Coal-tar creo-
sote, Federal Specification TT-W556,2 is recommended above all
others because of its repellent and lasting qualities, low viscosity,
ready availability in large quantities, and low price. Coal-tar creo-
sote and its fumes have a caustic effect on the skin, and this ma-
terial is also poisonous when taken internally. These facts should
be kept in mind when working with this material, and close contact
with it should be avoided as much as possible. Coating the hands
and face with petrolatum or cup grease helps to prevent creosote
Other materials have been found effective in the following order:
Naphthalene drain oil, gas tar, pine-tar oil, and wood creosote. Any
of these that have a strong odor of naphthalene, creosote, or phenol
can be used to good effect if it can be purchased cheaply.

The foundation for a creosote barrier is best made by throwing
up a ridge of earth with a plow, turning the dirt toward the corn.
A disk cultivator or small road grader may be used instead of a plow
if more convenient. The side of the ridge toward the bgs should
be smoothed and packed with a section of a harrow or a narrow drag
so that it is free from clods, cracks, or trash. If necessary, the upper
part of the ridge should be firmed with a shovel. A line of creosote
is then applied, as shown in figure 8, along the brow of the ridge
but not (hite ona top of it, so that the bugs are still climbing upward
whenI they reach it but are not yet at the top where they are liely
to be blown across the line by the wind. If the line is placed either
in the bottom of the furrow or on the top of the ridge, the foremost
2 Dalers in coal-tar creosote are usually familiar with these specifications. If not, a
copy of them may be obtained from the Superintendent of Documents, Washngton, D..C.
Price 5 cents,


bugs are likely to be pushed across by those crowding up behind
A convenient container to use for applying the creosote is a tin
or galvanized bucket in the side of which a hole has been punched
with an eightpenny nail. The hole should be about 1 inch from
the bottom so that it is not readily clogged, and should be directly
below the point where the bail is attached. The creosote is allowed
to run from this hole as the bucket is carried along the barrier. A
line one-half inch wide is just as effective as one 2 or 3 inches wide.
Therefore, only a small quantity is necessary for one application.
Fresh creosote should be applied to the original line at least once
a day for the first few days; after this, if care has been taken to
follow the same line each time, it need be renewed only once every
2 or 3 days, unless the weather is extremely hot and dry.

Frmuul 8.-A dirt-ridge creosote barrier. Very efficient if creosote line and post-lhole traps
are properly constructed and maintained.
When poured on the ground the creosote sinks in immediately,
making a brownish line on the surface, and giving off a strong odor
that is very repellent to the bugs. This repellent odor seems to be
all that keeps them from crossing the line, and if it has bee
erly located ery few actally do so. Light s te effect of
freshening th-ie creosoteas it is oil\y and comes to the srand oe wthen
then ioued on heget. When pro perly apied, 5sis of credsote
wimll Iainlt a (abrline of the fsurrc, a ier for about 3 weeks, wlhic
ordiarily is lolgert tha the barrier is reqlired.
lPost holes for fro roi the bugs sheolid be, d in the furrow from
1 to 4 rs aptht crd fosot, 18 to 20is ol cohe s ee to he siore uface lei
the bugs, the closer should be the holes.T y should e set part
way into the ridge, and their riims shuld le steeply fl:red all
around with the slole extended well up toward the creosote line.


The flared ring should also be kept covered with fine dust. The
bugs traveling toward the cornfield encounter the creosote line,
begin moving along it in an attempt to find a crossing, lose their
footing in the loose dust, and tumble into the post holes. Few of
them can crawl out if the rims of the holes are kept dusty. Trapping
the bugs in the post holes and destroying them is fully as important
as stopping their migration. This feature of barrier operation is
too often neglected.
After completion this type of barrier should not be dragged, and
it should be kept in good repair. The efficiency of the post-hole
traps must be maintained continuously by means of fresh dust
around their rims when needed. If dust is not available from the
dirt floor of a barn or shed, a bushel or so should be stored away
for use in case rain spoils that usually available in the field.
The bugs trapped in the holes should be killed every afternoon
at about sundown. An easy way of doing this is to sprinkle 1 or 2
tablespoonfuls of kerosene into each hole. Do not ignite the kero-
sene, but let the bugs work it around among themselves.

A paper-fence barrier has been developed and rather widely used
in Iowa and Illinois. It is made by setting upright in the ground
a strip of creosote-soaked paper about 4 inches wide, with half its
width above the surface (fig. 9). Experience has shown that the
4-inch width is the best for practical use, and that the strip is most
effective when placed 2 inches below and 2 inches above the ground.
This 2-inch fence of creosoted paper acts as a physical as well as a
chemical barrier and prevents the bugs from being blown across the
line by wind or crowded across by their fellows. It also helps to
avoid bridging of the line by straws, leaves, or dust; breaks in the
barrier due to cracking of the soil in dry weather; and injury to
the soil by the creosote. Although the treated paper fence is installed
with more difficulty than the creosote line applied directly on the
soil, it is less troublesome and expensive to maintain effectively in
all kinds of soil and weather when properly made with paper of
the right kind. Paper fences can be installed either on the usual
type of furrow and ridge described and illustrated above or on
clean, level ground as shown in figure 9. Where the barrier is
likely to be submerged by the accumulation of rain water in low
spots, its location on a ridge is preferable. After the paper has
been prepared, two men can build 80 rods of paper fence in about
4 hours.
Single-faced corrugated paper, tarred (not asphalt-treated) felt
paper of the 14- or 15-pound grade, red-rosin building paper of
the 30-pound grade or heavier, and heavy chip board or chip straw-
board ranging from 20 to 40 points in thickness have been sed
successfully. The choice of paper is usually determined by avail-
ability and cost. The rolls as purchased are first cut with a crosscut
saw into nIrrower rolls aIbout 4 inchles wide. With some papers it
is necessary to oil the aw blade or clean it occnsionally with kero-
sene. After being cut, the rolls should be soaked for at least 12
houlrs in a container with enoughl creosote to keep them covered.


They should ten be allowed to drain for an hour or more before
the fence is built.
The manner of erecting the treated paper fence depends upon the
tools available and the character of the soil. A handy tool for use
in unrolling and installing the paper strips may be made by fitting
a broom handle into a hole in the side of a piece of 2 by 4 about
a foot long, so as to form a T-shaped carrier, and slipping the roll
of paper own over the handle until it rests on the crosspiece at
the bottom. After a ridge or a smooth path free from litter has
been prepared, a wheel hoe or a garden cultivator with a small
plow attachment, or a corn cultivator with all but one shovel re-
moved, may be used to open a small furrow to receive the paper.

Diirecl&n of c/wcl
O' ra,- .

FIGtRE 9 .-Creosote-treated paper-fence lbarrier, a recent improvement over the creosote

When the ground is very hard, it may bi necessary to ue a turnplow.
In this case the paper is unrolled against the straight, or land, side
of the furrow anthe dirt isaked against it. In any eent it is
important that the dirt be packed firmly and evenly to the same
level on both sides of the paper, for if it is left higher on one side
than on the other, rain water or caving soil imay cauIse greater pres-
sure on the higher ide, resulting in collapse of the fence.
Post holes for trapping and killing the bugs are just as important
with paper felncs s with the ground-lile creosote barriers. They
should be dug every 1 to 4 rods on the side of the paper toward the
smaIllo dgrain and from 4 to 6 inches away from it, with their edges
sloped out almost to the paper and then )usted.
he par fen should repel the ugs for 2 or 3 days, if it as
been properly treated. Then it will have to be freshened by applying
more creosote close to the top ede of the paper. A t with a


hole near the bottom as described on page 15 can b used for this
purpose, but the application can be made much more easily if a cop-
per tube is soldered into the hole so as to extend downward for 12
or 15 inches, its end being curved sideways to direct the tream
against the paper. A horizontal prong is soldered to it close to the
lower end to slide along the top edge of the paper and act as a guide
(fig. 10). A single treatment of one-fourth mile of 2-inch paper
fence requires 2 or 3 gallons of creosote. After it is well soaked,
the paper barrier will not need retreatment so frequently as a creo-
sote line on the ground.
The treated paper barrier costs about the same as the dirt-ridge
ground-line creosote barrier. About 30 gallons of creosote will ordi-
narily be sufficient to maintain
Sa quarter of a mile of paper-
fence barrier for the season.
This is about two-thirds the
quantity required for the
ground-line type. Enough
paper for a quarter-mile of 4-
inch strips costs approximately
$2. With creosote at 20 cents
a gallon, the cost of paper bar-
S: rier would thus be $6 for the
i4 i creosote plus $2 for the paper,
or a total of $8 per quarter

C Another type of creosote bar-
Srier that found some favor in
Ohio in 1935 is made by using,
instead of the paper strip, a
special kind of soft rope about
one-half inch in diameter. A
FI;UI: 10.-Renewitng ,reosot, on a1per fence: smootBh, well-packed path is
A, IRetptacle with a copper tuble; fB, gide p
Iprong soldered near end of tube; (, apply- first made along the side of the
ing crfeoote to paper fene. (Iowva State lid to be p ed T r
Agricultural Experimlent Statio.) to be tected. he
is then laid in place on this
path and one end is threaded through a specially designed creosote
applicator, which consiss of a bucket containing a fixture earing
spools to guide the rope down into the creosote and out again on the
other side of the bucket. The end of the rope is then fastened to a
stake, and the applicator is carried along so that the rope runs
through it and drops hack soaked with creosote into its position on
the barrier path. The use of post holes to trap the bugs is just as
ssential with the rope barrier as withh the other types
The ro1 e barrier costs about tie he sm l ais thI I)aper fence or grolund-
line type of creosote barrier and can be installed more easily Wh.ler
a smooi path free from lumlps and cracks can be made, it is very
satisfactory. While it acts somewhat as a physical as well as a
chemical barrtier, it is not so esfcient in this respect as the paper fence
for it is easily knocked or blown out of place and, whee the ground
is lumpy or cracked, it des not make good contact with the soil


surface. Under such conditions the rope barrier is little, if any,
improvement over a ground line of creosote, because its effectiveness
then depends on whether or not the creosote dripping from the rope
has ormed an unbroken line on the ground beneath it.

A well-known type of barrier is made by pouring a narrow line
of coal tar or gas tar on a path made by smoothing and packing the
soil as firmly as possible along the margin of the field to be protected.
Chinch bugs are repelled by the odor of the tar, and while the tar
is fresh it also acts as a physical barrier because of its stickiness. Tar
makes a very effective barrier, but it has to be renewed oftener than
creosote. Where the proper grade can be obtained cheaply and
readily, its use is highly practical. Tars from which the creosote
and cresylic acids have not been distilled should be procured, for
tars from which these materials have been removed, and also tars
resulting from the manufacture of water gas, have little or no value
as chinch bug repellents. Post holes properly dug and maintained
are also essential to the effective operation of tar barriers.
It is possible to kill nearly all the chinch bugs along a barrier by
flaming with a large blowtorch, but this method is not recommended,
since practically the same result can be attained at much less expense
by the use of the post-hole traps. Bugs congregating on the outer
rows of corn may be killed by flaming them with a torch, but in
nearly every case the plants also will be killed. A better procedure
is to disk up the ruined portion of the field and plant it to soybeans.
The oldest and most widely used barrier consists of a dusty furrow
or strip around the field to be protected. The furrow type is the
best and is generally made by plowing a dead furrow, throwing tie
dirt both ways, and then dragging a log or trough of planks back
and forth in this furrow until the sides and bottom have been worked
down to a fine dust. Sometimes two parallel furrows are ploved,
and a double drag is constructed with a raised connection to span
the intervening ridge. Both furrows may thus he draged with
little more labor than would be required for a silgle furr l Effec-
tive dust barriers have also been maintained by repeatedly drageiino
a harrow back and forth over strip of ground aross tie field in
front of the bugs, thus working up a deep, finel ust mulch in which
the bugs are buried and killed as they crawl into it. No post loldes
are used with barriers that depend on a dust mulch for their effec-
On certain types of soil, and during dry weather, dust harriers
are very satisfactor. Wile dy they rlmain impassable to chinchl
bugs if frequently dragged, and most of the bugs tlhat fall into them
are killed by the drag, the heat of the sun, or te penetration of
fine particles of dust into their breathing tubes. Of course, dust
barriers are of no value during periods of rain. Often a heavy


shower ruins the dust mulch so that the bugs are able to cross in
sufficient numbers to destroy 1 or 2 acres of corn before a fresh dust
can be worked up. Also, in some soils it is impossible to make a dust
so fine that the chinch bugs cannot crawl through it. Although the
dust barrier does not require any costly equipment or the expendi-
ture of money for materials, constant labor is necessary to maintain
it, and the expense is often greater than for a more dependable and
efficient creosote or tar barrier.

A number of suggested chinch bug barriers have proved to be
practically worthless. Barriers made by planting a narrow strip of
some legume between the small grain and the corn are of little or no
value. Cowpeas or soybeans are the legumes most frequently used
in this way, but the bugs crawl throug them about as readily as
they would pass over the bare ground. It has also been suggested
that the bugs would feed upon freshly cut cornstalks laid in a con-
tinuous line along the margin of the grainfield, and would be
poisoned by this material as it soured. Numerous tests with this type
of barrier have shown that it is worthless. Occasionally considerable
numbers of cast-off skins of the bugs may be found scattered through
the cornstalks, and these are often mistaken for dead bugs. Close
examination, however, has failed to show that any chinch bugs are
killed by this kind of a barrier.
Spraying and dusting with insecticides are expensive operations
and thus far have not been found practical for controlling chinch
bugs in large fields of either small grain or corn. They are recom-
mended only as emergency measures where the bugs have invaded
small plantings of valuable seed corn. In such cases satisfactory
results require the use of an efficient knapsack sprayer or duster.
Since chinch bugs do not eat plant tissue, but feed only by piercing
the stems or leaves with their sharp beaks and sucking the sap, they
cannot be killed by poison sprayed or dusted on the plants. The
bugs themselves must be hit with a spray or dust that will kill them
upon contact. Thiis s usually difficult to do thoroughly, because
many~ of them are hidden unll( leaf shleaths and foliage or are
lilovlng about on the grollund.
One of the best sprays for this purpose consists of one-1a11f ounce
of 4(--pelrcent nicotine sullphate and 1 ounce of soap, dissolved in 1
g (llon of water. This spray will kill all bugs wet with it and is not
injurious to the corn except wheln alpplied so that it accumulates in
Ite 1heart or curl of the pllant. Where this occurs, the soap sometimes
kills tle leaves when the watle evaporates. Solutions mIade with
certalin o grdes f laundryv so,) without thle nicotile sulphate, make
fairly effective slrays. With soft water, 3 or 31/ ounces of soap to
a gallon is sufficienlt, ut mloe is necessary if the W'ter is hard. All
chinch bugs thoroughly wet with the soap solution will be killed, but
soap sprays must be used with caution, as they may injure the corn.


When chinch bugs are congregated on the first rows of corn, dust-
ing is sometimes more effective than spraying. Less labor is required
for dusting and, although the material costs more, dusting can often
be ne to better advantage. A few of the bugs on the outer leaves
of the plant may escape the dust, but nearly all can be killed. A
2.4-percent nicotine dust is harmless to corn plants, is very effective
in killing chinch bugs, and may be applied at a fairly rapid rate. It
is better to buy this dust ready mixed, especially if the quantity
needed is small.


For sale by the Superintendent of I)cuimewnts, Vashinitou, I). C. - rice 1i cs


3 1262 09218 4440

D : v i|

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