Practical methods of mormon cricket control

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Practical methods of mormon cricket control
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Wakeland, Claude
University of Idaho -- Agricultural Extension Service
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United States Department of Agriculture, Bureau of Entomology and Plant Quarantine ( Washington, D.C )
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E-470 April 1939

United States Department of Agriculture
LBRA RY Bureau of Entomology and Plant Quarantine
FATE PLApt' BOARD

PRACTICAL METHODS OF MORMON CRICKET CONTROL

By Claude Wakeland and W. B. Mabee, Division of Domestic Plant Quarantines,
and
Frank T. Cowan, Division of Cereal and Forage Insect Investigations



Contents

Page

I n t ro d u c t i o n ............................................................................... ............................ .... 2
H is to rica l .................................................. ........................ ................. .... 2
Geographical distribution ........... . ............. .................................... 2
D a m a gee .................................................................................................................... ............. 2
T y p e o f d a m a g e .................................................................................. ......................... 2
C r o p d a m a g e .................................................................................................................. 3
R a n g e d a m a g e ................................................................................................................ 3
Seasonal and life h isto ry ......................................................................................... 3
Stages of cricket development ........................................ 4
N a tu ra l con t ro l .................................................. ............. ............. ......... ........... 5
C l im a t ic fa c t o rs ................................................................................................ ..... 5
Parasites and predators .............................................. 5
Direct methods o f control ......................................................................................... 5
D u s t i n g ........................................................................................................................ 5
M a t e r ia l s u s e d .............................................................................................. ... ... 6
Power dusting ..................................................... 6
H an d du s t in g .... ................................................................... .................... ..... 8
D an g e r t o op e ra to rs ..................................................................... ........... ......... 8
D an g e r to l iv e s to ck ........................................................................................... 9
Effect of dust on crickets ............................................................................ 10
Oil-on-wate r ba rrie r ............................................................................................. 11
How and where to use it .............................................................................. 11
The use of water from oiled ditches ............................... 12
E effectiveness ............................................................................................... 12
M e ta l b a r r i e rs .................................................................... ................................ ... 1 2
Where and how to use them ............................................................................... 2
E f fe c t iv en e s s ....................... ................................................ 14
C a r e o f b a r r i e r ........ ..................................... .................................................. 1 4
Less effective methods ...................................................................................... 16
T r e n c h b a r r i e r ........................................................................ ............. ............... 1 6
P o i s o n b a r r i e r ............................................................................ ............... ........ 1 6
Water barriers ................................................... 17
Baits not recommended ................................... ........................................ .... 17
Importance of organization .................................. ........... 17






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INTRODUCTION

Useful facts concerning the Mormon cricket (fig. 1), its life his-
tory, habits, and thoroughly tested control practices for it are presented
in this circular, which will serve as a source of information and instruction
for supervisors, foremen, and others engaged in control of Mormon crickets.
There are included facts concerning crickets, their hosts, and their control,
obtained from foremen and workmen and from the field experience of the
writers, that should be of value to men who may be engaged in control cam-
paigns. The illustrations referred to in the text will be found at the back
of the circular.

There are several species and geographical varieties of the Mormon
cricket, all of which have not yet been determined. Their life histories
and habits are quite similar, and the control practices are identical. Life
history and habits mentioned in this circular refer particularly to Anabrus
simplex Hald.

HISTORICAL

The first recorded occurrence of Mormon crickets in outbreak numbers
dates from 1848. Bancroft, in his "History of Utah," describes very vividly
the outbreak of crickets which did considerable damage and threatened crops
of the early Mormon colonists in the spring of 1848. Since then Mormon
crickets have appeared periodically as a serious pest to agricultural and
range crops at various places throughout the Western Great Plains and Rocky
Mountain States. Mormon crickets normally develop and breed in foothill
areas, but they appear in tremendous numbers and migrate far from their
native breeding grounds.

GEOGRAPHICAL DISTRIBUTION

The accompanying map (fig. 2) shows the known distribution of Mormon
crickets as determined by the fall survey of 1938. At present these crickets
are a major insect problem in 10 States. They are now more widely distrib-
uted, in outbreak numbers, than at any time in their history, seriously
infesting, at the present writing, some 18,919,340 acres.

DAMAGE

Type of Damage

The kind of damage that crickets may do is extremely variable, de-
pending upon local conditions, the plants or crops available, and weather
conditions, as well as on the stage of development of the food plants or of
the crickets themselves. Cricket damage may be divided into two classes,
(1) injury to young plants and vegetation and (2) damage to native and
cultivated seed crops.

Although preferring certain plants as food, crickets may feed on
almost any type of available vegetation. Often their feeding is erratic,




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depending upon temperature or weather conditions. Frequently a band of
crickets is observed moving through a field without doing any appreciable
damage, only to stop in the next field and destroy the crop.

Crop Damage

During 1938 Mormon crickets were responsible, according to estimates
submitted by qualified observers, for causing destruction of crops on more
than 12,900 acres. Crop losses averaging 5.4 percent were also sustained
on approximately 236,000 additional acres. Cereal and forage crops suffered
the greatest loss, but garden crops were also damaged or destroyed.

Range Damage

Crickets normally inhabit and damage extensive areas of range land.
In 1938 359 species of known range plants were listed as damaged by Mormon
crickets. Damage in such areas varied with the intensity of the infestation
in each area, but in certain cases closely studied in 1938 this damage
amounted to startling reductions in livestQck-carrying capacity.

Mormon crickets are indigenous to the mixed prairie range areas
east of the Continental Divide and of the sagebrush type west thereof. It
has been determined that crickets in some localities prefer range plants of
the higher forage values, and it is apparent that they may be responsible
for greater range damage than has heretofore been realized. They undoubtedly
are a serious factor in the rehabilitation of the range areas in some parts
of the West.

Early in the growing season and while the crickets are still im-
mature, damage is confined principally to succulent vegetation. Later, as
the plants and the crickets mature, the crickets turn their attention to the
seed. In the cultivated crops, such as small grains, damage to the seed is
of variable importance, depending upon the depletion of the particular range
on which crickets are feeding or whether the principal range forage is an-
nual or perennial. In cases where range is seriously depleted through
overgrazing or drought, the destruction of the grass seed may be of major
importance.

SEASONAL AND LIFE HISTORY

There is one generation of crickets annually. Only the eggs remain
over the winter, hatching very early in the spring at low temperatures. The
newly hatched crickets remain near the egg beds for several weeks, feeding
on very young vegetation, clustering for protection from cold, or basking
in the sunlight for warmth. As they gain size, the bands of crickets grad-
ually disperse and soon begin migrating. Later they are in continuous
migration throughout the summer. They stop only for feeding, molting (shed-
ding their skin), mating, and egg laying.

The Mormon cricket matures early in the summer. In reality a long-
horned grasshopper, it has only rudimentary wings and can travel only by




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walking or hopping. The males use their rudimentary wings to make a chirp-
ing sound, but the females make no noise. These insects are cannibalistic
and greedily devour any weakened individuals.

The females begin laying eggs early in the summer. The eggs are
normally laid in groups of about 40 to 50 over a period of 1 to 3 days,
followed by a nondeposition period of from 5 to 7 days. Mating usually
occurs during this latter period. Each female will mate several times during
the egg-laying season. Not always, but generally, they prefer for egg lay-
ing soil that is rather compact but not too hard, and usually they select
areas that are reasonably free of vegetation. This selectivity of egg beds
varies some in different localities. A little preliminary search, however,
should soon indicate the specific conditions that are attractive in any
particular location. Under adverse conditions the crickets attempt to de-
posit eggs anywhere.

The long ovipositor of the female is worked into the ground to its
full length, and the eggs are deposited singly, never in pods like grass-
hopper eggs. Sometimes many eggs are laid within a very small area, but at
other times they are scattered. Female crickets have been known to lay as
many as 298 eggs in a season, although the average under field conditions
is probably nearer 150. Most of the egg laying is concentrated in "egg
beds" on sunny slopes, where the soil is suitable. Eggs are laid from early
in the summer until cold weather arrives, but do not hatch until early the
following spring.

During 1938 there was apparently more variation in the hatching dates
of crickets than had been previously observed. In some areas crickets
hatched as early as late in February and in other areas they were observed
hatching as late as July 4.

Crickets normally have seven periods of development or instars before
becoming mature. The skin is shed between instars. Technical Bulletin
No. 161, of the U. S. Department of Agriculture, indicates the easily seen
differences between these instars. The early stages of crickets are rather
difficult to distinguish, especially those of the males.

Stages of Cricket Development

The first and second instars are difficult to distinguish without the
use of a binocular or strong hand lens. The ovipositor is just starting to
develop and is not visible to the naked eye. When the crickets first hatch,
they are light colored but soon darken until they are uniformly dark brown
or black with a few white markings. When the female reaches the third
instar the ovipositor is visible but still does not extend beyond the tip
of the abdomen. When it reaches the fourth instar the ovipositor definitely
extends beyond the tip of the abdomen. Until this stage the crickets have
been nearly uniformly black. Color variations first appear during the
fourth stage. In the fifth instar the ovipositor is twice as long as it
was in the fourth, being now about one-third the length of the hind femur
(large part of hind leg). Color is more in evidence, ranging from tan and
pastel shades through the greens to dark browns. In the sixth instar the





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ovipositor again is twice as long as it was in the previous instar and
three-fifths as long as the hind femur. In the seventh instar the ovi-
positor has reached its full length and is now a little longer than the hind
femur or twice as long as it was in the sixth instar.

The mature cricket has no longer ovipositor than in the seventh in-
star and is practically the same size. However, the seventh-instar female
can be distinguished from the adult because the stubby wing pads on her
back do not meet in the center. In the adult stage the wing pads on the
female definitely meet in the center, and the wing pads of the male overlap.
Bright color variations in the adult tend to disappear. They darken with
age from dark brown to black.

NATURAL CONTROL

Climatic Factors

It is believed that the greatest natural factor in the control of
crickets is a combination of weather conditions, Just what circumstances
tend to reduce the cricket population to normal numbers has not yet been
determined. Large outbreaks of crickets usually follow prolonged periods
of drought, but they may extend into the better crop seasons. It is hoped
that these climatic factors may be determined so that outbreaks may be
forecast with accuracy.

Parasites and Predators

Many birds, mammals, and insects feed upon crickets, but none to such
an extent as to be an important factor in natural control,

Only one species of parasite is known to attack cricket eggs. This
is a small wasp (Sparaison pilosum Ashm.) which develops within the cricket
egg, the larva feeding upon the egg contents and emerging as an adult wasp
late in the summer in time to infest the new crop of cricket eggs. This
parasite has been observed in many areas, but in only a few has it occurred
in sufficient numbers to affect the cricket population materially.

Another insect (Palmodes laeviventris Cress.), a large black digger
wasp, is predacious upon crickets. In a few instances this has been numerous
enough to effect slight cricket reductions, but it, in turn, is parasitized
by another insect.

DIRECT METHODS OF CONTROL

In this circular only control practices which have proved to be
effective for general field use are discussed.

Dusting

The most satisfactory and outstanding method of cricket control now
known is dusting with arsenical mixtures.





-6-


Materials used.--The use of sodium arsenite as a dust for cricket
control was first tried and developed by Frank T. Cowan during 1926. Sodium
arsenite dust proved so successful in experimental work that it was used
extensively in Montana in 1927, on control operations in Lake and Sanders
Counties.

At first the dust was composed of 1 pound of sodium arsenite to 4
pounds of lime. During recent years, however, diatomaceous earth, a cheaper
material and much less irritating to the skin of the operator, has replaced
lime.

Diatomaceous earth is mixed with sodium arsenite at the rate of 3
pounds of the earth to 1 pound of sodium arsenite. The arsenite is the
poisonous ingredient and the lime or diatomaceous earth acts only as a
diluent. The purpose of the diluent is to facilitate even distribution of
the small quantities of sodium arsenite. The amount of the mixed dust used
will vary somewhat with the population of crickets, from 5 to 7 pounds per
acre being sufficient in most cases.

These ingredients mix readily. Mixing usually is accomplished in a
cement mixer, an abandoned creamery churn, or, in small quantities, in a
barrel which has been mounted diagonally on an axle. To adapt the cement
mixer for this work a tight cover for it is constructed so that dust cannot
escape while the mixer is in operation. If the mixer is not overloaded or
not run too fast, 10 minutes' time is sufficient for combining these in-
gredients satisfactorily.

Power dusting.--In the past dust was applied by hand-operated dusters.
Recently, however, power dusters have been introduced and have been found
far superior to hand dusters, both in quality of work and efficiency of
operation. One power duster (costing about $100) mounted upon a small pick-
up truck and operated by one man and a driver does as much work and does it
better than a crew of 20 men using hand dusters.

New methods of mounting power dusters make it possible to take these
machines into country that formerly was considered too rough for their
operation.

One of the most satisfactory ways of mounting a power duster is to
mount it in front of a car or truck, as illustrated in figure 3. Mounted as
in figure 3, the duster can be operated by one man. As the booms and
nozzles are in clear view, the operator can avoid obstacles and damage to
his machine. This mounting has the added advantage of not flushing or alarm-
ing the crickets before the dust is applied.

Another very satisfactory method of mounting this duster is on the
rear of a pick-up truck. Care should be exercised in the construction of
the booms in this mounting so that damage will not result from accidental
striking of obstacles. Figures 4, 5, and 6 illustrate a satisfactory way
to construct the booms to avoid damage and to allow them to be folded for
transportation to and from the field,




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Another method of mounting a power duster, which has been used very
satisfactorily in Wyoming, is on a two-wheeled trailer. The boom construc-
tion is the same as illustrated in figures 5 and 6. However, this trailer
is equipped with a coupling so that. it can be attached to the back of a car
or truck. It is also equipped with a substitute tongue that can easily be
attached so that the duster can be pulled by a team, This is a decided
advantage in rough country, as it can be operated wherever the team can be
driven.

Care should be taken, however, in using horses to pull dusters late
in the season, especially where vegetation is scarce. The reason for this
is that as the crickets grow large they are easily disturbed, and the slow
movement of the team may cause a high percentage of them to go olit of reach
of the duster.

Considerable difficulty was previously encountered in the use of
power dusters, because vibration damaged various parts and caused break-
downs. Every duster should be very firmly mounted on a-substantial base to
prevent twisting or vibration when operated in rough country. All duster
operators should be instructed to keep these machines ti_1tly fastened at
all times, and each operator should be equipped with a wrench, pliers, screw
driver, and a special set-screw wrench. This latter is necessary to keep the
0
set-screws tight on the shaft which operates the agitator. When these set-
screws become loose, they soon cut the shaft and repairs become more dif-
ficult.

Very little oil should be placed in the air-cleaner of these power
dusters. The bottom of this filter should not be filled with oil to the
indicated line. If this quantity of oil is used in rough country it will
get into the carburetor and choke the engine. The result is a lot of extra
cranking to restart the engine, and often the oil then becomes diluted with
gas and penetrates the magneto, causing further difficulties. These filters
are equipped with an air-cleaning material which is usually sufficient in
itself. If oil is used, it should be sparingly applied in the removable
top part of the filter and not poured into its stationary base,

Another difficulty encountered with power dusters has been that
operators have attempted to apply more dust than the machine is capable of
discharging. Some operators have made the grave error of enlarging the ports
in the feed mechanism. This has caused overloading of the engine, spilling
of material from the fan-housing, and irregular discharge of dust. A
satisfactory quantity of dust, sufficient for control, (5 pounds per acre)
can be most evenly and effectively distributed by the use of a flaring, flat
nozzle. No port enlargement is necessary. The diagram and pattern for the
ready construction of such a nozzle are shown in figure 8 and the completed
nozzle in figure 7,

Practically all power dusters in the past have operated without
nozzles on the ends of the discharge tubes. Without a nozzle the dust comes
out in a round stream and does not cover a very wide area. In order to


LIBRARY
STATE PLANT WARD




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produce the cloud of dust which is necessary, operators sometimes increase
the discharge. This in turn overloads the equipment, and a considerable
proportion of the dust that does emerge drifts away with the wind and may be
wasted.

This nozzle as illustrated should be on all dusters. The flat, fan
shape, with the two baffle plates, seems to distribute the required amount
of dust in the proper direction (laterally). It is thus easy to secure even
distribution from the small power dusters over a width of about a rod.
Nozzles also prevent streaking of the ground with dust, which frequently
occurs when dusters are used without them. This streaking is an unnecessary
waste of dust and also increases the hazard of livestock poisoning. The use
of a suitable type of nozzle almost entirely prevents streaking and gives
better distribution of dust and better control of the crickets,

Hand dusting.--Where there are rough areas infested with crickets on
which it is impossible to use a power-operated duster the hand-operated gun
is of most value, and for efficiency's sake the use of hand dusters should be
confined to such areas as coulees and arroyos where it is impossible to use
power dusters. Hand dusters are very effective for use in the early part of
the season on cool mornings. Advantage may be taken of the clustering habits
of crickets by using hand guns to dust such concentrations. Hand dusting
should be considered only as supplementary to power dusting.

Danger to operators.--Where common sense is exercised there is slight
danger of any internal poisoning occurring when working with sodium arsenite.
However, certain precautions should be taken for the prevention of external
injury among the workers. Medical examination is required for laborers
employed on Federal funds. Any individuals who show a predisposition to skin
rashes, irritations, or respiratory disorders and those who may have dia-
betes, tuberculosis, or syphilis should be rejected.

Duster operators working should wear shoes or boots high enough so
that the pant-legs can be tied down over them to prevent dust from gaining
access to the bare skin and causing irritation. Operators of hand dust guns
should wear aprons of tightly woven material that will prevent any excess
dust from working into the clothing. Operators, of course, should take
every advantage of wind direction and avoid, as much as possible, breathing
the dust. Where they are continually exposed to the dust, they should wear
a respirator and goggles.

Most of the commercially made respirators are not satisfactory because
they have a tendency to chafe the face at the points of contact. The most
commonly used dust mask and one that is very satisfactory is a home-made
affair, constructed of a simple wire clamp in which are placed strips of
cellocotton. This material excludes the dust, will not chafe, and can
readily be replaced. The most common source of cellocotton, if it cannot
be purchased locally in rolls, is from sanitary absorbent padding sold by
druggists.





-9-


Sodium arsenite causes skin irritation, particularly at any points
where chafing may occur due to perspiration. Such conditions should be
guarded against by the operators. Tight clothes, tight belts, or dust
masks that rub or chafe cause the most difficulty. Where an individual is
exposed to much dust, the exposed surfaces of the skin should be well covered
with zinc oxide powder, talcum powder, or diatomaceous earth when the others
are not available. All operators working continually with this material
should take daily baths, and their clothing should be frequently washed.

An operator who develops any skin irritation or arsenical burns should
immediately be laid off and treated until the irritation disappears. Plenty
of soap and water is the best preventive. The most satisfactory treatment
is a saturated solution of photographer's hypo (sodium hyposuiphite) applied
to the irritated places and allowed to dry. If "hypo" is not available, a
solution of common baking soda may be used. Any cuts or abrasions on the skin
should be covered and entirely protected from the dust.

Danger to livestock.--There is practically no danger of livestock
poisoning from dusting for Mormon cricket control if the dust is applied
properly. Almost without exception, cases of poisoning observed have been
due to the carelessness of the operators. The danger involved is entirely
confined to spilling the dust in quantities upon the ground or leaving dusting
equipment or dusting supplies exposed in places accessible to livestock.

It may readily be seen that where the dust is uniformly applied at
the rate of about 5 pounds per acre, the mixture would contain actually
11 pounds of the poisonous sodium arsenite per acre, the remainder of
the 5 pounds being made up of the harmless diatomaceous earth. Obviously
it is extremely difficult for livestock to eat sufficient vegetation to
secure an injurious amount of poison where so little poison is distributed
on an acre of land.

Crews applying poison are usually supervised by Federal, State, or
county agencies. These crews are well trained and careful in the applica-
tion of dusting materials. For the protection of trained crews, working
under the supervision of public agencies, release of liability should be
secured from land owners. These releases should conform to the laws of the
State in which the dusting is being done. Although it may be unnecessary,
ranchers should be given the opportunity to move livestock from areas to be
dusted previous to dusting, if they so desire.

Livestock in control areas should be kept well salted, as salt-hungry
cattle and sheep are likely to search out and lick up any sodium arsenite
that may have been carelessly spilled.

Every dust gun operator should be carefully and definitely instructed
to operate his gun in such a way as to prevent ground streaking and spilling
of dust. When any materials are spilled by accident, the operator should
be held responsible for throughly disposing of the poison so that it is in-
accessible to livestock. Any employee careless in this respect should
be severely disciplined.





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When not in use, all dusting equipment, machines, trucks, trailers,
and containers should be stored under lock and key in buildings safe from
children or livestock. As soon as operations have been completed, all
equipment should be thoroughly cleaned of poison and the residue destroyed by
burying it deeply in the ground or by scattering it so thinly over the
ground that animals cannot pick up a poisonous dose of it. Paper or burlap
containers should be buried rather than burned, because burning does not
destroy the arsenic.

Effect of dust on crickets.--Crickets are killed by sodium arsenite
apparently principally as a result of cleaning the material from their
feet and antennae by their mouths. In this way the dust is taken into the
digestive tract and acts as a stomach poison. In the cases of early-instar
nymphs the arsenite acts also as a contact poison.

When dust is applied to crickets, they show marked signs of irrita-
tion, become very nervous, and continue their migration almost continuously
until the poison kills them. Advantage may be taken of this knowlecge in
clearing a field of crickets or driving them into oil or metal barriers. It
is often possible to rid a grain field of crickets without dusting the entire
field. Where grain is nearly ripe and considerable shattering would result
from complete dusting of the field, it may be protected by dusting several
swaths through one side or around two sides of the field. The crickets
immediately start moving, and this induces others to migrate, so the whole
field soon may be vacated. Advantage may be taken of this behavior by
dusting the rear and flanks of cricket bands to hasten their march into
oil or metal barriers.

Because the sodium arsenite is slow in action, crickets, especially
when fully grown, do not die immediately. Some die within about 12 hours,
but the total kill is not secured until the third or fourth day. Often,
then, the results of dusting may appear discouraging until a more detailed
search is made.

Dusting as a control practice is most effective in the early stages
of development when crickets cluster, and such control is most easily
accomplished early in the season previous to migration. Hatching beds and
the closely clustered bands of very young crickets can be dusted by the
coverage of much smaller acreages and with smaller quantities of material
and labor than is possible later after migration has begun. Dusting is
effective, however, against crickets throughout the season, although con-
siderably larger territory must be covered to obtain equally satisfactory
results. In some cases late dusting has interfered with mating and egg
laying to a sufficient degree to reduce subsequent infestation.

Dusting during high winds is not effective, as the dust does not pene-
trate deeply enough into the vegetation to come in contact with the crickets,
but drifts away in the air and is wasted. Dusting during wet weather or
when excessive dew is on the foliage is likely to cause severe burning to
the vegetation.





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The use of nozzles on power dusters, as described previously, directs
the dust under higher pressure so that dusting may be done effectively in
windy weather. The dust distribution produced by these nozzles also prevents
excess quantities of the dust from being discharged in any one spot; there-
fore, there is less danger of burning vegetation. Under certain con-
ditions, when air movement is not too rapid, advantage of the drift may be
taken to cover a larger swath than the actual width of the booms.

Oil-on-Water Barrier

The use of oil on irrigation ditches and streams is one of the oldest
methods of control, but was developed and used extensively in Wyoming in
1936 and 1937. It has proved an excellent means of cricket control where
the circumstances permit, Crickets in their migration disregard irrigation
streams or ditches and do not hesitate to march into the water and swim
or float along until they can secure a footing and proceed on the other side.
In this way streams and irrigation ditches ordinarily are a source of
distribution of crickets and may carry them for great distances into new
areas. Thus these ditches, when covered with a thin film of oil, form an
excellent barrier which not only stops the progress of the crickets but
kills them,

How and where to use it.--Oil drippers, consisting of an oil barrel
with a shingle-nail hole punched in it, may be distributed at intervals of a
half mile to 1 miles along ditches, depending upon the size and rate of
flow of the particular ditch and the number of crickets entering it. The
important point is to maintain a very thin, continuous film of oil on the
surface of the water. Of course, after migration has passed, the oil should
be shut off, to be turned on again when another band approaches the stream.

The important qualities required of the oil are cheapness and ability
to form a film quickly on the water's surface. Oil that floats in large
globules without filming is unsatisfactory. The best oil yet found has been
a low-grade distillate. This oil is straw-colored, is thin, and does not
clog the openings in the barrel. It runs freely, continues running with
very little attention, and quickly forms a film on the surface of the water,
a small amount covering a very large area.

There has been a tendency on the part of some workers to favor the
use of a heavy crude oil because of its very low price. The sludge and
sediment in these low-grade oils are a constant source of vexation, contin-
ually clogging the oil drippers and necessitating an undesirable amount of
attention. As these heavy oils do not form a film readily, much more oil
must be used upon the water. The use of these excessive quantities of crude
oil on irrigation ditches, with their attendant disagreeable odors and un-
sightliness on the vegetation, causes many growers to be prejudiced against
oil as a means of control. The use of the more expensive distillate is a
genuine economy when all points are considered.





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The use of water from oiled ditches.--The question has often arisen
about the danger to crops from water that is covered with a film of oil or
the use of oiled ditches as a source of water for stock. Where the oil is
applied, as it should be, in only a thin film, it does not interfere in
the slightest degree with stock-watering purposes nor does it injure the
livestock in any way. In cases where animals have received unusual amounts
of oil owing to carelessness, this acts only as a laxative.

At the cut-outs, where the water is to be removed for irrigation
purposes, the following two methods of removing the water from the canal
without taking the oil into the fields may be used: (1) Put a board cover
over the cut-out so that all the water going into the lateral comes from
below the surface. (2) Place a baffle plate (a board) so that it extends
out into the stream just above the cut-out. When this has been done, a film
of oil on the surface is by-p-ssed around the cut-out and no oil enters the
lateral.

In rare instances objections have been made to oiling because certain
residents secure drinking water from the ditches. In such a case oil-free
water may be secured by inserting some type of frame which directs the oil
film around the point where the water intake is located.

Effectiveness,--Oil barriers, a cheap method of control, should be
employed wherever there are irrigation ditches, canals, or streams across
which crickets are migrating. For irrigated areas of intensive farm crops
threatened with invasion, there is no more effective protection than oiled
ditches as just described. As in the case of metal barriers, too much de-
pendence should not be placed on oiled ditches alone. They have their place
in a control program but they must be supplemented with well-planned dusting
operations.

Metal Barriers

Many types of fencing have been used to stop the migration of cricket
bands. Wooden boards having a narrow strip of tin or oilcloth tacked along
their top edges at right angles have been used with varying degrees of suc-
cess. Recently, however, galvanized sheet iron has been reduced in price and
has proved so far superior in actual field control that it is well worth the
additional cost over the above-mentioned substitutes.

Where and how to use them.--The metal barrier most commonly used con-
sists of 10-inch strips of 28-gauge galvanized sheet iron which is sold either
in 100-foot or 50-foot rolls. For most purposes the 50-foot rolls are advis-
able on account of ease and convenience in handling them.

In placing this barrier across the path of migrating bands it is
necessary to clear the ground of vegetation along a narrow strip where the
barrier is to be erected so as to prevent the vegetation from forming a
ladder for the crickets to climb. The barrier is then erected along this





- 13 -


cleared strip and staked down. Metal stakes, each of which is U-shaped at
the top, are preferable. These are placed on the side of the barrier away
from the advancing crickets. A small quantity of soil is then shoveled and
packed against the barrier on the same side as the stakes to fill any holes or
uneven places in the ground which might permit the crickets to crawl under
the barrier.

In placing a barrier across a road it is necessary to form some type
of gate or trench to prevent crickets from following the road or crossing
bridges. The simplest and most effective way of preventing crickets from
crossing a bridge is to dig a narrow trench, about 10 inches deep, across
the road. This should be dug preferably along the abutment of the bridge.
Then it is only necessary to insert one 10-inch plank within this ditch, as
the abutment forms one side of it. The front opening of this trench is then
faced with metal barrier which continues on out to the regular line of bar-
rier or down into the oiled stream, as required. This trench is constructed
narrow enough so that cars may easily pass over it. Such trenches need
little attention to keep them free of dirt. Crickets, approaching one side
or the other, pass on through the trench and across the road. Migrating up
the road, they enter the trench and, failing to climb the barrier on the
other side, progress along the trench across the road and on along the barrier
or into the oiled stream. Where this road crossing is not located at a
bridge, it is necessary to place planks on each side of the trench across
the road to prevent traffic from caving in its sides.

It must be borne in mind that metal barrier merely stops the migration
of crickets and must be accompanied by some form of trap. In order to
collect and destroy crickets as they accumulate along the barrier, many
types of traps have been devised. Pits and various forms of pit traps are
satisfactory, but considerable labor is required to construct and maintain
them. The metal pen trap has proved the most satisfactory. The advantages
of this are that very little labor is required to construct it and a minimum
amount of attention thereafter.

Figures 9 and 10 and the diagrammatic "floor plan" and cross section
in figure 11 show the proper construction features of a good pen trap.

There are a few points that should be strictly observed in the con-
struction of the trap illustrated (see fig. 11). The most important feature
is to have narrow entrances (not less than 12 or more than 18 inches wide).
Crickets enter more readily where they are crowded and the force of the flow
pushes them over the incline into the trap. Where an entrance is too wide
and the crickets are not crowded, when they come to the edge of the drop-
off and survey the situation, they attempt to go back and around the edge
of the trap. Where the entrance is narrow and the crickets are crowding in
rather rapidly, they have no alternative but to proceed over the incline and
into the enclosure.





- 14 -


The wings of the trap should be relatively long and funnel-shaped in
order to collect the crickets into a crowded condition so they will proceed
inward. The reverse curve at the ends of the wings has been found an added
advantage in preventing a backward wave or movement. When crickets are
startled or scared, the shape of this curve has a tendency to check this
backward movement and to direct them toward the entrance.

The piece of metal located at the front center of the trap is to
direct the crickets out of their line of march into the large area of the
enclosure, thus preventing them from proceeding directly to the opposite
entrance and clogging it up. Because of the crowded conditions, crickets
die rather quickly when confined in these traps. The trap entrances should
be cleaned frequently and dead crickets shoveled either out of -or to the
center of the enclosure. Where but one trap is used continuously for a long
period, its inside walls should occasionally be cleaned with a brush and
water to prevent the crickets from gaining a foothold and climbing out.
One point that should be stressed with all workers is that no dusting or
other activity which would scare the crickets should be carried on in front
of the barrier, as this may interfere with the free march of crickets along
the barrier and into the traps.

Effectivenes.--Another point that should be brought to the attention
of all workers is that the barrier in itself merely stops migrations. To be
of greatest advantage, the barrier must be supplemented with a dusting pro-
gram. Where crickets are migrating, dusting should be done at the rear and
flanks of the band in order to force them all into the traps and thus destroy
the whole band. Without this supplementary program, barriers often have
acted merely as concentration points for crickets and have not killed or
prevented them from laying eggs along the barrier.

Metal barrier is best used as follows:

(1) Mobile units can be placed in front of migrating bands until the
band is destroyed, then moved to a new location for a similar purpose.

(2) Where there is a definite continued movement of crickets through-
out the season in small areas, metal barrier, with the proper up-keep and
attention to the traps, may be used to excellent advantage.

(3) Metal barrier is excellent for use in connecting breaks between
irrigation ditches or streams or in directing the crickets around siphons or
underpasses in irrigation canals or ditches, thus supplementing an oil-
barrier control operation.

In every case where metal barrier is used, it should be supplemented
with a well-planned dusting program or a combination of oiling and dusting.

Care of barrier.--Metal barrier, purchasable for about $210 a mile
1938), lasts for a long time if properly cared for. The material is too






- 15 -


expensive to be handled carelessly by workers, and it is advisable that the
following instructions for its care be given:

(1) In laying metal barrier the same edge should be placed in the
ground each successive year. The contact with the ground causes a certain
amount of pitting and corrosion which roughens the metal. If both edges
become corroded, as occurs when one edge is put in the ground one year and
the opposite edge the next, the crickets may climb over the roughened sur-
face.

(2) Metal stakes with hooked tops are best, as it is then unneces-
sary to drive nails through the barrier metal, which would cause additional
rough places and provide more footholds for climbing crickets.

(3) When building a trap it is advisable to use one complete 50-foot
roll for the main border of the trap rather than to cut a roll.

(4) In cutting pieces of metal for trap entrances, cut all short
pieces from the same roll and use these repeatedly for this purpose. This
practice has not always been adhered to, and this has caused unnecessary
work in making up uniform 50-foot rolls from the odd pieces remaining at the
end of the season.

(5) In taking up the barrier to move it from one point to another,
or at the end of the season's operations, it should not be pulled out of
the ground with trucks or teams of horses. This procedure stretches and
distorts the tin so that it becomes extremely difficult to roll, to handle,
or to run it through the barrier conditioning machine. The barrier should
be removed carefully to prevent this distortion.

(6) All nails should be removed from the metal.

(7) To facilitate handling and later operations, the metal strip
should be rolled uniformly on some type of winder with a diameter of not
less than 7 inches. Where the barrier is wound too tightly it becomes
bent, causing waves that are difficult to remove, thus making cleaning much
harder at the end of the season. Figure 12 illustrates a simply constructed
winder that any crew can put together quickly.

(8) Barrier should always be stored in a dry place and preferably
upon a floor of some type that will not absorb or hold moisture. Much bar-
rier metal has been damaged by being stored on dirt or cinder floors that
accumulated moisture and caused corroding and pitting on one edge.

(9) All barrier metal should be cleaned at the end of each season's
work so that it will be free of dirt and corrosion and ready for the folllow-
ing season's operations. Old barrier that has not been properly cleaned is
not nearly so effective in stopping the march of crickets.





- 16 -


(10) Care should be taken to keep the metal as clean as possible
throughout the season. A few precautions taken during the summer will save
an untold amount of work at the time of fall clean-up. If metal barrier is
used around oiled ditches, guard against crude oil or heavy greases coming in
contact with it, as they are extremely hard to remove. If burners are used
to kill crickets in traps or for other purposes, by all means keep the flame
away from the metal. Burned metal will not clean satisfactorily and is
practically useless in stopping cricket migrations.

Almost any type of device that will wind the metal barrier into
rolls with a diameter of not less than 7 inches will suffice. The diagram
in figure 12 may serve as a guide for its construction.

When a 50-foot roll has been completely wound, a piece of baling wire
is tied loosely around it. The metal then is unwound by hand until this
wire becomes tight. This loosens the metal roll from the cylinder. The
hinged end support is then dropped and the roll removed,

Less Effective Methods

During past outbreaks a variety of devices and materials have been
used. Other methods than those explained in this circular in detail have
not proved practical, so only brief mention is made of a few that have proved
partially effeQtive.

Trench barrier.--Trench barriers have been used effectively in some
areas to stop migrations of crickets. The success of a trench barrier is
dependent upon the presence of a light sandy soil. There are few soils in
which such a barrier can be cheaply dug where it will maintain its shape
without too much repair. The trench barrier, to stop crickets, must be at
least 2 feet deep and maintain a clean-cut, perpendicular wall facing the
advancing crickets. The trench should be at least 18 inches wide, and the
soil which is removed therefrom should be piled on the side away from the
advancing crickets. In order to prevent the trench from becoming filled,
pits should be dug at intervals the full width of the trench and at least
2 feet deep. As these pits fill with crickets, they should be coverd with
soil and new pits constructed. Although the trench barrier is one of the
oldest means of stopping migrating crickets, its use has been largely
abandoned because of the tremendous labor cost involved in construction and
particularly in maintenance. The use of this barrier is limited to areas
of the proper type of soil and has been largely replaced by the metal barrier,
which is easily moved from place to place.

Poison barrier.--Poison barriers have occasionally been constructed
by placing a streak of poison dust along the ground or in furrows, These
barriers are only partially effective and then only for a short period or
until the poison becomes caked from moisture. Because they are such a great
danger to livestock, their use should be forbidden.




- 17 -


Water barriers.--Before the extensive use of oil on ditches and
streams, barriers were floated on the top of the stream for the purpose of
collecting and directing the floating crickets into traps at the edge of the
stream. These barriers were constructed of heavy pieces of timber upon
which an upright piece of tin was tacked. Crickets floating down the stream
would crawl upon the timber and, failing to climb the tin at its back, would
then progress along it to the edge of the ditch or stream, where they were
directed into pits or traps. This type of water barrier has been largely
discontinued since oil has been found so effective when used on irrigation
ditches and streams. However, there may be unusual circumstances where oil-
ing is undesirable and where these barriers would serve to good advantage.

Baits not recommended.--Many bait formulas have been experimented with
in the past in an attempt to secure a bait that would be as effective as
grasshopper bait. Under certain conditions baits have proved valuable, but
until further research work is done, baits are not recommended.

Many mechanical devices, including burners, have been used, but their
effectiveness has been so limited that their use has been discontinued.

IMPORTANCE OF ORGANIZATION

Cricket control is primarily not a problem for the individual farm
operator, even though it has been repeatedly demonstrated that an individual,
by the use of proper methods and much diligence, can save his crops. Crick-
ets breed on and disseminate largely from range areas and nonagricultural
lands. They usually cover such large acreages and migrate so rapidly that
their control is logically a problem for a whole community and, in larger
areas, control becomes a Statewide and Federal problem. All agencies con-
cerned have a definite responsibility in control operations. In the States
where crickets occur there are large areas of Federal, State, and county
lands, in addition to the lands of nonresident, corporate, and resident
owners. If cricket control is to be efficient, all agencies must contribute
a share to control operations, and it is only through such cooperation that
large-scale control can be accomplished











































Figure l.--Male (upper) and female (lower)
Mormon crickets (natural size).


















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Figure 3.--Front mounting of power duster.


This duster is mounted on a wooden frame which is bolted to
two heavy angle irons which, in turn, are bolted to the frame of the
car. To be most effective, this machine should be equipped with
nozzles.


Figure 4.--Rear mounting details of a power duster.


This is a 5-horsepower duster mounted on the rear of a pick-up
truck. In this picture the outlets are located closer to the ground
than they should be in actual operation.



























Figure 5.--Side view of rear mounting.


Side view of mounting in figure 4, showing the details of
boom supports and method of folding booms for transportation.


Figure 6.--Boom construction.

Details of eye-bolt attachment of booms. This method of
mounting permits flexibility of booms. They are held forward in
place by springs, and supported by ropes knotted and run through
notches in the tops of the uprights as seen in figures 4 and 5.
These features prevent breakage in case the booms strike obstacles.



























Figure 7.-The completed nozzle.

This picture shows the completed home-made nozzle attached
to the outlet hose.



Explanation of figure 8.--Pattern for nozzle construction.

This pattern is actual size and may be used as a template for
cutting the nozzle from tin. The construction of this nozzle requires
no particular skill. It is merely cut out of tin with a pair of tin-
snips, folded as indicated, and soldered together.
A. The part in the diagram marked "A" forms the main body of
the nozzle. Two pieces should be cut, as illustrated, and the edges
bent am indicated. One piece forms the top, and the other forms the
bottom of the nozzle.
,. Two pieces should be cut, as indicated, the exact shape and
size of "B." These pieces act as baffle plates to divide the air and
dust stream evenly through the nozzle. These two pieces, when cut,
should be bent and fitted into the holes marked "b" between the top
and bottom of the nozzle; in other words, between the two pieces
marked "A." The projecting lugs are then clinched and soldered in
place.
C. The piece "C," when bent to form a tube, forms the entrance
to the nozzle and the connection for joining the nozzle to the outlet
hose. "C" is fitted into the nozzle at "c-l," and when all parts are
fitted properly the seams are soldered.
The opening or lip of this nozzle should be not more than
three-sixteenths of an inch in width.







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Figure 9.--A pen trap in operation.


Figure 1O.--Details of construction of pen entrances.















































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Figure 1.-Diagra5 showing construction details of pen trap.


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Figure 12.--A barrier-metal winder,

A. Hinges are used as indicated by "A" on the first support
so that thin support may be dropped out of the way for removal of
the finished roll of metal. The other supports for the axle are
similar to the one in "A" but not hinged.
B. "B" indicates a groove that is sawed into the cylinder of
the winder. The end of the sheet metal is fitted into this groove
and rolled on the cylinder by turning the crank. This cylinder may
be made of the end of a straight fence post or a block sawed from a
log, its principal specification being that its diameter should be
uniform and not less than 7 inches.
C. The axle is fastened rigidly to the wooden cylinder of the
winder, by a collar and lag screws. This collar is fastened rigidly
upon the axle by a bolt which runs through both the collar and the
axle.
D. The axle and crank are made from any pipe of suitable
diameter that may be on hand, inch-and-a-quarter pipe being preferred.




UNIVERSITY OF FLORIDA

3 1262 09224 6742