UNIVERSITY OF CALIFORNIA PUBLICATIONS.

COLLEGE OF AGRICULTURE.

AGRICULTURAL EXPERIMENT STATION.

STUDIES IN GRASSHOPPER CONTROL

By J. S. HUNTER.

Small Orchard and Vineyard Defoliated by Grasshoppers.

BULLETIN No. 170.

(Berkeley, June, 1905.)

SACRAMENTO:
w. w. shannon, : : : : superintendent state printing.

1905.

BENJAMIN IDE WHEELER, Ph.D.. LL.D., President of the University.

EXPERIMENT STATION STAFF.

E. W. HILGARD, Ph.D., LL.D., Director and Chemist. (Absent on leave.)

E.J- WICKSON, M. A., Acting Director and Horticulturist.

W. A. SETCHELL, Ph.D., Botanist.

ELWOOD MEAD, M.S., C.E , Irrigation Engineer.

C. W. WOODWORTH, M.S., Entomologist.

R. H. LOUGHRIDGE, Ph.D., Agricultural Geologist and Soil Physicist. (Soils and Alkali.)

M. E. JAFFA, M.S., Assistant Chemist. (Foods. Nutrition.)

G. W. SHAW, M.A., Ph.D., Assistant Chemist. (Starches, Oils, Beet-Sugar.)

GEORGE E. COLBY, M.S., Assistant Chemist. (Fruits, Waters, Insecticides.)

RALPH E- SMITH, B.S., Plant Pathologist.

A. R. WARD, B.S.A., D.V.M., Veterinarian and Bacteriologist.

E. W. MAJOR, B.Agr., Animal Industry.

A. V. STUBENRAUCH, M.S., Assistant Horticulturist, in charge of Substations.

E. H. TWIGHT, B.Sc, Diplome E.A.M., Viticulturist.

F. T. BIOLETTI, M S , Viticulturist.

WARREN T. CLARKE, B.S., Assistant Field Entomologist.
H. M. HALL, M.S , Assistant Botanist.

, Assistant Entomologist.

GEORGE ROBERTS, M.S., Assistant Chemist, in charge of Fertilizer Control.
C. M HARING, D.V. M., Assistant Veterinarian and Bacteriologist.
C. A. COLMORE, B.S , Clerk to the Director.

R. E- MANSELL. Foreman of Central Station Grounds.

JOHN TUOHY. Patron, )

- Tulare Substation, Tulare.
, Foreman, )

\ Southern California Substation.

J. E McCOMAS, Patron, Pomona,

J. W. MILLS, Superintendent, Poniona,

In charge Cooperation Experiments in Southern California,

, Assistant Superintendent, Ontario,

J. W. ROPER, Patron, )

V University Forestry Station, Chico.
HENRY WIGHTMAN, In charge, )

ROY JONES, Patron, )

[- University Forestry Station, Santa Monica.
-, Foreman, )

VINCENT J HUNTLEY, Foreman of California Poultry Experiment Station, Petaluma.

The Station publications (Reports and Bulletins), so long as avail-
able, will be sent to any citizen of the State on application.

STUDIES IN GRASSHOPPER CONTROL

By J. S. HUNTER.

Introductory Note. — The present bulletin presents some of the results obtained in a
rather extensive and quite successful effort to prevent grasshopper injury. The work
was started by myself in 1903, with the assistance of Mr. William La Grange, a student in
the department; but the success of the practical work has been largely due to Mr. J. S.
Hunter, whose energy and persistence through the campaign of 1904 has not only
resulted in the prevention of extensive injury during that season, but has also taught
the ranchers in the affected section so well that serious damage will probably not be
permitted to occur again in that region.

The work was rendered possible through the hearty cooperation of the people of

that section, and I wish particularly to mention the financial support afforded us by the

firm of Hultberg & Soderberg, of Turlock, and the personal interest of their manager,

Mr. Hallmer.

C. W. WOODWORTH.

During the summer of 1904 grasshoppers did extensive damage in
several sections of the San Joaquin Valley. Perhaps the most seriously
infested region was in Merced County, where a great deal of injury was
done. The two- localities particularly infested with the insects were a
district bordering on Stanislaus County, south of Turlock, and the
country immediately south of Newman.

Grasshoppers began to be observed at Turlock early in May. The
insects had done considerable damage in this region during the previous
summer, and an attempt had been made by the University to locate
accurately and stake out the breeding grounds, in order that they might
be plowed by the ranchers during the following fall or winter, or at
least to afford a knowledge of the places most liable to be affected this
year. The breeding grounds were not plowed, nor were they watched
in the early spring for the purpose of attacking the young grasshoppers
as early as possible after they emerge from the eggs. They appeared in
much greater numbers than in 1903. Hatching must have occurred in
April or earlier, for when we were notified in the middle of May the
grasshoppers were almost grown and threatened to devastate the country.
At the very urgent request of the people of the Hilmar Colony, the
writer was sent to superintend a campaign against the grasshoppers in
that district.

In order to explain the situation thoroughly a brief description of the
infested regions may be necessary. At Turlock grasshoppers first began
to do damage in what is known as the Hilmar Colony, comprising some
six or seven thousand acres. Formerly this land was all planted to
wheat and rye, but for a number of years previous to being colonized
in 1902 it had been left idle, so that it had approximately reverted

4 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION.

to its original condition. At present about half the land is under
cultivation, being for the most part planted to young orchards, vine-
yards, alfalfa, and ordinary field crops. In many cases these cultivated
places are surrounded by uncultivated fields. It was in this idle land
that the grasshoppers of the previous year had deposited their eggs,
and consequently it was here that they first were noticed, moving
afterwards on to the green crops in the cultivated portions.

At Newman the grasshopper-infested district on the other hand is,
so to speak, one large alfalfa field, which is divided into smaller ranches.
The grasshoppers were more or less numerous on about two or three
thousand acres.

The grasshoppers in this region began to work during May, but were
not regarded as a serious matter by the ranchers until a month later,

Fig. 1. Long-legged Grasshopper (Clinopleura melanopleura), female. Notice long ovipositor.

about the first of July, when the University was appealed to for aid,
since the losses had become so evident that the ranchers were thoroughly
aroused.

There were two species of grasshoppers that did the greater part of
the injury, and four other species that were abundant enough to con-
tribute materially to the losses sustained. Other species were also
present, but not in sufficiently large numbers. Several of these might,
however, under favorable conditions, become as troublesome as those
discussed in this bulletin.

The Long-legged Grasshopper (Clinopleura melanopleura), Figs. 1 and
2, the least injurious of the four species, is a katydid. This species was
found at Turlock, and in some parts of the colony was very common,
but still not numerous enough on any cultivated portion to do damage
had the species been alone, but it did augment, quite appreciably, the
loss occasioned by the more prevalent grasshoppers.

STUDIES IN GRASSHOPPER CONTROL.

The Pale-winged Grasshopper (Melanoplus uniformis), Fig. 3. — This
species was, during the summer of 1903, the most troublesome kind in
the region southeast of Turlock. It
was the first species to be noticed fly-
ing in any considerable number, and
the only truly migratory grasshopper
that was found at either Turlock or
Newman. It is a rather restless species
after becoming winged, and as a rule
did not remain in any one spot long
enough to do any perceptible damage.
A considerable swarm has been ob-
served feeding on a field of. alfalfa
during a month without apparently
injuring the crop.

The first movement of this species
was noticed after a high northwest
wind on June 2d and 3d. Many
swarms of grasshoppers were seen
flying, for the most part, in a north-
easterly direction. Swarms of grass-
hoppers at this time came on to land
that previously had been free. After
this for a month, during the last hours
of the day and when the wind was
not blowing hard, grasshoppers could
be seen moving toward the northeast. Toward the middle of July the
flight seemed to be in a northwesterly direction. At no time, however,
was there another as general a movement as the one that occurred on

June 5th. During the latter
part of September a swarm of
grasshoppers that had estab-
lished themselves on a large
idle field northwest of Turlock
took wing and flew rather low
over the town in a south-
easterly direction.

This species seemed to be
rather slow in coming to full
maturity; pairing was not ob-
served previous to the middle
of August. Egg-laying was under way by the first week in October, and
at that time nearly all the females contained well-developed eggs.

The Devastating Grasshopper (Melanoplus devastator). — Late in June
grasshoppers were reported as doing extensive damage in the foothill

Fig.

2. Long-legged Grasshopper (Clino-
pleura melanopleura) , male.

Fig. 3.

Pale-winged Grasshopper (Melanoplus
uniformis), male.

UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION.

region below Mariposa. It was thought best to make a trip through
that region and learn, if possible, what danger there was of the grass-
hoppers moving down into the valley. The territory from Snelling to
Raymond and from White Rock to as high as Wawona was thoroughly
gone over. Grasshoppers were found more or less over the entire
region, but only in certain sections were particularly abundant. The
species M. devastator is a true foothill species and has often developed
migratory habits. Egg-laying, as a rule, is done almost exclusively in
the foothills. According to the reports, about once in seven to nine
years they become so numerous that all the cultivated land in the foot-
hills will be stripped, sometimes even taking the leaves from the oak
trees. At such times there is danger of their moving into the valley.
In 1904 they were nowhere near as thick as they had been in years past.
None of the methods that are practical in the control of the grass-
hoppers in the lower valley seem to be very much so in the foothills.
Burning is about the only method that can be used. If the grass-
hoppers are confined to a
small area and a sufficient
force of men is obtained so
that the fire can be kept
under control, it will of
course destroy the insects.
A fire once beyond control,
however, will sweep over
valuable pasture lands and
might work up into the still
more valuable timber lands
farther up in the hills.
Poisoning is hardly to be considered in the breeding-grounds, because
of the large area to be covered, but might be useful in the smali culti-
vated portion, though even there the grasshoppers may work in from
the outside in such large numbers that all vegetation will be destroyed.
The grass on the ranges is seldom permanently injured by the work
of the grasshoppers, the loss in this region being confined to the few
fruit trees around the ranch houses and to garden spots. In some cases
this year these gardens had been most thoroughly cleaned out. One
patch of corn was seen where nothing was left but the hard outside por-
tion of the stalk, the pith even being excavated by the insects.

Hesperotettix Sp. — This species, which was rather abundant at New-
man, is much smaller than the dominant form and is dark brown in
color. The males are very short-winged, the wings not reaching half
way to the end of the body. The females are much longer-winged.
Although rather abundant, the damage done could scarcely be noticed
alongside of that done by the larger M. differ entialis. The species, on
account of its short wings, is easily caught in the dozer. Pairing was

Fig. 4. Valley Grasshopper (<Edaleoiwtns enigma).

STUDIES IN GRASSHOPPER CONTROL.

under way during the latter part of June. Those noticed laying eggs
did not do so in the ordinary manner, the hole, on account of the size
of the species, not being very deep and for the most part drilled straight
into the ground.

The Valley Grasshopper {(Edaleonotus enigma), Figs. 4 and 5. — This
species was by far the most destructive at Turlock, causing fully ninety
per cent of the losses. It was present throughout the entire Turlock dis-
trict, being most numerous in the Hilmar Colony. Both the short- and
the long-winged forms were noted, the former being the more common.
There was some migration in the case of the long-winged form of this
species, but not so much as for M. uniformis. The species reached
maturity about June 1st. Pairing was first noted on June 2d, but it was
not until the 24th of the same month that eggs were found, on dissection,
large enough to be laid. Up to the middle of August, however, although
careful watch was kept, no grasshoppers were
found laying eggs, but on a trip to the region
in the early part of October, both this species
and M. uniformis were found laying in con-
siderable numbers in certain fields.

The egg-laying is not greatly different from
that of most other species of grasshoppers.
With the four hard horny points on the end
of the abdomen, the female drills a hole in the
ground about half an inch deep. She then
ejects a small amount of a white, frothy paste,
and then places the eggs in regular order hori-
zontally until all of the developed eggs in the
oviduct are deposited. With each successive
layer she ejects more of the same frothy sub-
stance, which soon hardens, forming an almost
waterproof capsule around each egg-mass and
cementing the eggs firmly together. More of this substance is used for
rilling the hole. She then draws, with the end of the abdomen, small
grains of dirt over the hole, covering it so securely that even with the
closest observation it can seldom be found. The places usually chosen
for egg-laying are those thinly covered with vegetation and where the
ground is rather firm — the most compact soil, indeed, found in the
region ; but the Turlock soil is for the most part comparatively loose
and sandy. The full complement of eggs is usually placed in one hole.
This will be normally about twenty-five.

The egg-laying of the previous species is almost identical with that of
0. enigma, but perhaps with greater care taken in concealing the hole.
Both species are easily disturbed when laying, and will quickly jump
or fly from the hole.

Fig 5. Valley Grasshopper.
{(Edaleonotus en igma).

UNIVERSITY OP CALIFORNIA— EXPERIMENT STATION.

THE CAMPAIGN AT TURLOCK.

Burning the Young Grasshoppers.- — During the first few weeks of the
work against the grasshoppers the method of destruction employed was
that of fire. This we found could be effectively used only on land that
had considerable grass. The greater part of the grass and weeds at
that time of the year is dry enough to burn freely, but a great deal of the
land affected by grasshoppers was rather bare. When the fire travels
fast everything is swept before it, the grasshoppers being killed before
they hardly have time to leap. When the fire progresses slowly they
may at first jump about confusedly ahead of the fire; and when the fire

Fig. 6. The preparation of the " firing line."

comes near them, they become bewildered and attempt to hide in the
grass.. Some may occasionally escape by crawling into holes in the
ground, others by hiding in a patch of weeds too green to burn. For
the most part, however, until large enough to fly, the flames destroy at
least ninety per cent of the hoppers.

Burning the Winged Form. — After nearly three thousand acres of
land had been burned the grasshoppers on unburned land had devel-
oped wings. These enabled so many of them to escape the flames that
it was considered useless, except under unusual conditions, to depend
on burning. The best results then seemed to come from night work.

The nights being cool, the grasshoppers were not as active as during
the day and many more were caught by the flames, but still the work

STUDIES IN GRASSHOPPER CONTROL

was not as successful as during the nymph stage. Enough were killed,
however, to amply pay for the trouble of burning the grass. Unusually
oool and windy nights were found to be the best. Under these condi-
tions the grasshoppers were less active, and with the flames sweeping
rapidly across a field most of the grasshoppers would be caught. The
most successful results were obtained by firing from both sides of the
field. Where the insects were thick a line of dead grasshoppers could
be distinctly seen where two such fires came together.

Burning was more successful with 0. enigma than with M. uniformis,
the former not being as active. That species could possibly also be
destroyed more effectively by burning later in the season than at an

Fig. 7. Burned area on the right, showing control of fire by " firing line."

earlier date, on account of the fact that the wings become frayed out
and the bodies heavier, so that the grasshoppers would be less able to
fly out of the flames.

Burning is to be recommended only where the pasture burned over is
of no great value and where the grasshoppers are seriously threatening
orchards or other cultivated fields. Care will always have to be taken
that the fire is kept under perfect control, as any damage resulting can
be charged to the person starting the fire.

Poisoning the Grasshoppers. — After burning was done, the grasshop-
pers that escaped moved into cultivated fields. These fields may be
divided into two classes; alfalfa and other field crops forming one class,
and orchards and vineyards the other.

The most successful means of fighting grasshoppers in orchards and

10 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION.

vineyards was by poisoned bait. The " Criddle mixture, " recently
highly recommended in the East, did not prove very satisfactory. The
formula is as follows: 100 pounds of horse dung, 1 pound of paris
green or powdered arsenic, and 2 pounds of salt, adding enough water to
moisten but not make soggy. The failure of this mixture was because
very few of the grasshoppers were found to eat it at all. This may be
attributed to the fact that under the dry condition of the interior valleys
the mixture would dry out too rapidly. At any rate, it did not seem
to have any power of attracting the grasshoppers. Probably later in
the season this formula might have been used more successfully, judging
from the fact that, although early in the summer very few grasshoppers
were seen on the piles of horse-droppings along the roads, later in the
year such piles would be covered with the hungry insects. The mix-
ture can not be recommended except where the grasshoppers are observed
to be attracted by horse-droppings.

Far different was the experience with the formula of grasshopper
poison that has been used so many years in various parts of California.
The proportions used were:

Bran 40 pounds

Molasses (cheap) .. 2 gallon-
Arsenic 5 pounds

The above amounts of material will be enough to fill a good-sized
tub. It will be found easier to mix only .half the given amounts at a
time. The stronger 'smelling molasses used seemed to be the more
attractive to the grasshoppers. In a number of cases where molasses
could not be obtained, black honey was tried, but it did not seem to be
as good as the molasses for attracting the insects. Paris green can be
used in place of arsenic, but the latter is considerably cheaper, costing^
in quantities, less than ten cents a pound.

In order to get the best results from the bait, considerable care must
be taken in mixing it. It was found most successful to mix the bran
with enough water that a lump held in the hand will only slightly
drip unless squeezed. The molasses can then be added, mixing it thor-
oughly with the hands. After this has been well done, the arsenic
can be added. This can be worked into the bran with the hands or
with a paddle. There may be some danger in using the hands to mix
this poison if there are cuts or sores, and care should be taken in
removing any arsenic that may have lodged around the finger nails.

Another method is to mix the arsenic and bran in a barrel with a
shovel, or in a mortar-bed with a hoe; then dilute the molasses with
water and work it in as in mixing mortar. In any case, mix it thor-
oughly. It is a good plan to let the material stand from twelve to
twenty-four hours, then remix it, so as to allow the arsenic that is
dissolved to soak well into the bran.

STUDIES IN GRASSHOPPER CONTROL. 11

The usual practice is to place as much poisoned bait as can be held
in a soup-spoon in a pile on the ground; or, perhaps better, on a shingle
at the base of each tree or vine. If the grasshoppers are coming into
the orchard from one side only, poison need only be placed along the
first six or eight rows of trees. It was found very effective in such cases
to place a series of piles of poison, about a foot apart, along the threat-
ened side. As soon as the poison is dry it should be moistened, as the
grasshoppers will not eat much of it when it is dry.. In our experi-
ments it was found that when properly mixed, the bait was evidently
preferred to the foliage of fruit trees. The placing of the poison on
a board is recommended in order that it may be gathered up after
the danger from grasshoppers is over. Serious results to stock may
accrue if the poison is left in the field and cattle be allowed to get
hold of it.

In some cases the poison was scattered broadcast over the orchard,
but the results obtained were by no means as satisfactory as from the
other method. The poison in such cases dried quicker and afterwards
could not be remoistened conveniently.

When grasshoppers are gathered in bunches, as along irrigation
ditches, they can be poisoned by the thousand. A striking illustration
of the immediate effectiveness of the poison occurred in a large pasture.
There the grasshoppers had bunched in the shade of six or eight locust
trees around an old, deserted ranch house, and when first found, they
covered the ground and were crawling up the trunks of the trees
by thousands to get the green leaves. Poison was put out, and on the
following day fully seventy-five per cent of the swarm were dead, and
a few days later scarcely a live grasshopper could be found. In places
the ground was completely covered by dead grasshoppers.

While live stock, and especially chickens, are very liable to be poi-
soned if they are allowed to have access to the grasshopper poison,
there seems to be very little danger of poisoning beneficial wild birds;
for careful watch was kept while the poison was out for any that might
have got hold of either the poison or the dead grasshoppers, and not a
single dead bird was found.

Effect of Poison on the Grasshopper. — When the grasshoppers are
hungry, as they are when they come in from the dry pastures, they
very greedily eat the bran. In some cases they piled up on the poison
so that nothing could be seen but a mass of struggling, kicking insects.

After eating until gorged, the grasshopper crawls slowly away, hunt-
ing a shady spot. There it remains quiet until the effect of the poison
becomes more acute; then a twitching or kicking of the rear legs will
be noticed. These convulsions become quite violent in some cases; in
others, there will be none at all. It is usually from eight to ten hours
before any dead will be noticed. Afterwards they die slowly for about

12 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION.

eight hours more; from eighteen to twenty-four hours the greatest death-
rate occurs. As soon as grasshoppers begin to die, the ones that have not
yet eaten poison will begin to eat the dead ones. Numbers will be
killed in this manner, but it is not known for how many successive
individuals it will be effective. In orchards w T here clean cultivation is
practiced, the poison is more effective than in those where weeds are
allowed to grow. All species of grasshoppers do not take the poison
as freely as 0. enigma. M. uniformis is one of these. As a rule, the
more active the grasshoppers, the less likely are they to take the poison.

If grasshoppers come into the orchard in such numbers that they
must be taken care of at once, more active and quicker methods of
protecting the trees must be employed.

The use of the hopper dozer is not as effective in the orchard as
in the alfalfa fields. In fact, when the grasshoppers are on the trees
and not on the ground, not enough will be caught to pay for running
the dozer. In vineyards a dozer can be used more successfully. The
use and construction of the hopper dozer is given later in this bulletin
under a different heading.

In young orchards, two or three years old, it is a very good plan to
wrap the trunks of the trees with strips of cloth. This not only protects
the bark from grasshoppers, but, in case the leaves are eaten, it prevents
the bark from becoming sunburned. If it is only a drifting swarm that
temporarily threatens the orchard, and the trees are not too large or too
many, they can be covered with sacks of burlap or other cloth. It will
be necessary to tie the sacks securely around the trunks and leave no
holes large enough for grasshoppers to crawl through, or they will get
inside and badly injure the tree. These sacks can not usually be left
for any great length of time, or the tree will be weakened. However,
some small orchards at Turlock that were covered for a month or longer
came through very nicely. Yearling vines were saved in some cases by
turning the soil over them with a cultivator. In such cases the soil
must be taken away as soon as the danger is past. Even then the vines
may be killed.

Smoking the Grasshoppers. — The two species of grasshoppers common
to Turlock can be smoked or smudged out. Very good results were
obtained by placing piles of rather damp manure on the windward side
of the orchard and other piles in rows, a hundred yards apart, through
the orchard. This manure, when burning, gives off a dense smoke,
which is not liked by most species of grasshoppers. When once on the
wing, they will keep on flying until entirely out of the smoke. It was
found more satisfactory to go through the orchard after the smudges were
started and shake the trees, forcing the grasshoppers to take wing.
Smoking as long as the grasshoppers threaten the orchard proved very

STUDIES IN GRASSHOPPER CONTROL.

successful in numerous cases. During cool nights smoking was not suc-
cessful, nor was it as a rule successful early in the forenoon or late in
the afternoon.

Crude oil makes a very good smoke, but under usual conditions is too
expensive to be used extensively. Any substance that will make a good
pungent smoke will be satisfactory. A small quantity of sulfur may
be put on the fire, but there is considerable danger of causing the leaves
to drop from the trees if the fires are too close or too much sulfur is
used.

Smoking was most successful when there was a rather stiff breeze
blowing, so as to keep the smoke close to the ground. In connection
with the smoke, one very good way of trapping the grasshoppers was
by putting rows of straw, sprinkled with water sweetened with strong
molasses, on the leeward side of the orchard. Many of the grasshop-

Fig. 8. Hopper dozer with strainer to save the oil removed from the pans when the

grasshoppers are shoveled out.

pers, on coming to this straw, will take refuge in it, being attracted by
the molasses odor. Later in the day, when they become less active,
this straw can be burned. The same method can be used when grass-
hoppers are coming into a field from an adjoining one. In some cases
they will gather on the straw in sufficient numbers to cover it.

Sometimes the grasshoppers come in so persistently that more
extreme methods must be used in order to save the trees. One farmer,
in addition to poison, smoke, dozers, and other methods, had his entire
family turn out before daylight in the morning to kill the grasshoppers
on the trees. On account of his energy and persistence, he lost very
few trees from the pest. His place was one around which the grass-
hoppers were thicker and more persistent than around any other farm
in the locality.

Unless the trimming done by the grasshoppers is too severe, it results
only in the setting back of the trees for that year. If the leaves and
bark are stripped from the limbs, the tree will usually die. In all

14 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION.

cases after the grasshoppers had stripped the trees, it was found best to
irrigate them as soon as Avater could be obtained. In a number of
cases, although the trees were very severely trimmed, they put out new
leaves and quite a growth was made before fall. Vines, for the most
part, stand the severe treatment much more successfully than trees,
provided they are not allowed to suffer for water. Vines two years
old or over will stand very severe pruning by grasshoppers.

HOPPER DOZERS.

In alfalfa, when the grasshoppers began to do damage, they were
destroyed very successfully by means of hopper dozers. A hopper
dozer may be made in the form of a long, shallow pan of galvanized
iron, placed on runners, with a back of stovepipe iron about 3 feet

Fig. 9. Hopper dozer with burlap backstop and braced ends.

high. The pan is partially filled with crude oil, a horse is hitched to
either end, and the machine dragged across the grasshopper-infested
field. The grasshoppers jump at the approach of the dozer and, striking
the back of the pan, fall into the oil and are quickly killed. The dozer
can be made of any convenient length up to 16 or 20 feet. The longer
the dozer, the more quickly a field can be gone over. Where the check
system of irrigation is used and the checks are small, a large dozer can
not be conveniently used. But where the checks are large and levees
low, or where the furrow system is used, the longer lengths are more
desirable.

Construction of a Dozer. — For a dozer 16 or 20 feet long, a strong
frame or platform is necessary. The pan can be made in one piece 16
feet long and 28 or 30 inches wide, turned up in front about 3 inches
and behind about 4 or 6 inches. Three or four cross partitions are

STUDIES IN GRASSHOPPER CONTROL.

necessary to keep the oil from running to one end when that end hap-
pens to be lower than the other, or the pan can be made in shorter
lengths of the same width, placed end to end. If in short lengths, lighter
iron can be used and consequently will not cost as much as the heavy.
Galvanized iron from No. 20 to 26 will be satisfactory for this pan.

In the construction of the platform on which the pan is to be placed,
it should be borne in mind that the closer the pan is to the ground the
more grasshoppers will be caught. Where several short pans are used,
it will be necessary to have a frame into which they can be set and held
firmly. Such will also be necessary where light iron is used for a long
pan. No. 20 iron is stiff enough as that there is considerable strength
to it alone, and it is not necessary to have such a strong frame as for

Fig. 10. Wide hopper dozer in operation in alfalfa field.

the lighter iron. At least five runners are necessary on a 16-foot dozer.
These can be made of old wagon tires, bent up in front. Three
of them should be turned at right angles at the back, in order that
uprights may be fastened to them that will hold the backstop. Two- or
three-inch boards fastened to these runners will protect the bottom of
the pan from wear. The 2 by 4 piece in front must be very strong; and
in order that the full width of the dozer be available, the ends should
extend beyond the pan at least 2 feet. A board at the back, set on edge,
will give additional strength. A cross-piece should be placed at the
other end of the pan to hold it from sliding. The figure on page 14 will
show the method of constructing a very serviceable dozer. It was found
best to use stovepipe iron for the backstop, as the grasshoppers, on
striking it, would fall immediately into the oil. Burlap was used at
first, but on striking it many of the grasshoppers would cling thereto

UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION.

and escape without getting oil enough to kill them even though the
oloth was saturated with it. A brace and a backstop fastened to the
ends of the dozer directly behind the horses will be found to improve
the machine.

After the dozer is run for a few minutes, so many grasshoppers will
be caught that those which jump into the pan will not get enough oil
on them to kill them. It will then be necessary to clean the grass-
hoppers from the pan. A good-sized box with the bottom knocked out
and a piece of half-inch mesh wire put on in place of it, will be found
very convenient for straining the oil from the grasshoppers when they
are shoveled out of the pan.

If the bottom of the dozer pan is not well protected, it will soon wear
out. It was found that with a good dozer and a team of fast-walking

Fig. 11. Differential grasshopper (Melanoplus differentialis).

horses, the grasshoppers could be cleaned out of a field to such an extent
that the damage done by those left would not be noticed.

Some species of grasshoppers, being less active, are more easily caught.
0. enigma, during the hot part of the day, are so active that until the
wings become worn, a large part of them will fly over the backstop.
The best success in combating both this species and M. uniformis was
had during the early morning and late in the afternoon. Some days
the dozers were run as late as twelve o'clock at night with good success.
Later than this the grasshoppers, for the most part, become so slug-
gish that they will not jump at the approach of the dozer and will be
run over and not killed. After going over a field one way, better suc-
cess was had by going back over it in the opposite direction. When
•grasshoppers keep coming into the alfalfa, it will be necessary to use
the dozer every day; but usually, after running over the field two or
three times, so large a number will be caught that those left will not do
great damage.

STUDIES IN GRASSHOPPER CONTROL.

Poisoning was not successful in the alfalfa fields. Not enough grass-
hoppers were killed to pay for putting out the poison. In such cases
the alfalfa foliage is preferred to the poison, and the grasshoppers will
scarcely touch the latter. Smoking is even less effective. The grass-
hoppers crawl down among the stems of the alfalfa out of the smoke
and can scarcely be made to fly. It is likely that enough grasshoppers
will be left in the alfalfa fields, even after the dozer has been used, so
that if conditions are favorable there will be a good batch of eggs the
following spring. Such being the case, some method, such as disking,
should be employed to destroy the eggs which are deposited.

Fig. 12.

Differential grasshopper (Melanoplus
differentialis), young.

THE CAMPAIGN AT NEWMAN AND LOS BANOS.

The Differential Grasshopper (Melanoplus differentialis) . — This grass-
hopper was practically the only species at Newman that became
abundant enough to do serious injury. It actually did, however,
the most damage of any species this year. The losses sustained were
chiefly due to the fact that
nothing was attempted against
the pest until late in the sea-
son. The country about New-
man was a very striking
example of the amount of
injury that a grasshopper is
capable of doing. A very con-
servative estimate places the
loss due to the work of this
grasshopper at $10,000, while
some claim that it was not less
than $30,000. These estimates are based on the damage to alfalfa alone
no consideration being taken of the injury done to small home orchards
and vineyards, and other less important crops. (See frontispiece, also
Figs. 13 and 14.) When it is understood that this damage was done
on an area of from 1,000 to 1,500 acres, the really serious loss to the
individual ranchers can be appreciated.

This grasshopper was for the most part hatched in the alfalfa fields.
There had been some slight damage done the previous year, but not
enough to cause much apprehension. This year, however, they began
to be noticed as damaging alfalfa about the first of June, and they kept
at it energetically until the middle of August before they were under
satisfactory control.

There is a striking difference in color between the young grasshop-
pers and the adults. This gave rise to the belief that there were at
least two different species concerned in the work. The nymph, or
young, is bright green in color and changes slightly with each succes-

UNIVERSITY OP CALIFORNIA — EXPERIMENT STATION.

sive moult; and suddenly, when becoming adult, changes to a rather
light yellow. This subsequently changes gradually with most individ-
uals, becoming much darker.

There was one large brood produced quite early in the summer, but
the hatching of some of the eggs was greatly delayed and was very
irregular, as young grasshoppers could be seen as late as October.
About the middle of July, after a large part of the damage these grass-
hoppers are capable of doing had been clone, the University was
appealed to; and acting on the advice given, many of the ranchers
began the use of hopper dozers. It was not too late to demonstrate that-
great good could be accomplished by the use of the dozers.

In many fields the grasshoppers were so thick that not only were the
old leaves and bark trimmed off, but as fast as new growth would start
that would be taken also. In a few cases this had been kept up so per-

Fig. 13. Vineyard defoliated by grasshoppers near Newman.

sistently that the alfalfa was apparently dead. Usually one could see
a very great difference in a week's time, after a field had been run over
three or four times with the dozers. In this way one or two cuttings
were obtained from fields which would not have yielded anything had
the grasshoppers been left alone, and the alfalfa revived enough to be
in good condition to be pastured during the fall. This species, how-
ever, is much more easily caught in the dozer than the species occurring
at Turlock. It is of a more sluggish nature and will not fly to as great
an extent. More of the grasshoppers would be run over by the dozer
than would get over the top of the backstop.

Poison was not tried on this species, because the only places where it
could have been used were the small orchards adjoining the ranch
buildings, where there was considerable danger of stock getting hold of
either the bait or the grasshoppers after they had eaten poison. There
is no reason why the poisoned bran would not work very successfully
with this species, as it is a voracious feeder.

STUDIES IN GRASSHOPPER CONTROL.

Smoking was tried, but with poor success. The grasshoppers would
stir around a little when the smoke first struck them, but after becoming
accustomed to it would pay no attention whatever to it. Burning
would have been a very good way of getting rid of large numbers of
the grasshoppers, but this could not be done at Newman.

This same grasshopper was also common at Los Banos, although on
the whole nowhere near as much damage was done. They were not
confined to one section, but were scattered over quite a considerable
territory, only in an occasional field being numerous enough to do
extensive injury. In some of these places even more serious damage

Fig. 14. Orchard trees from which leaves and fruit had been removed by
grasshoppers. Pits shown still on the tree.

was done than at Newman. On one ranch not only was the crop of
alfalfa for the year lost, but the trees around the house were stripped,
many being killed. Even olive and fig trees were damaged to a con-
siderable extent, although these two kinds of trees were in most cases
left alone. Practically nothing was done against the grasshoppers.
Two different ranchers had some success with crude dozers made out of
old wooden troughs. But for the most part it was too late in the season
to make it worth while to do anything, after it was learned that some-
thing could be done.

The species was abundant the year before at Dos Palos, doing consid-
erable damage there, but this year, with one exception, there was

UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION.

scarcely any injury. This exception was on one of the Miller & Lux
ranches, where a small vineyard had been stripped of its leaves and the
fruit consequently ruined. A few trees of an adjoining orchard had
also been considerably injured. Grasshoppers were quite common in
other places, but not enough so to do any noticeable injury.

Egg-laying. — The egg-laying of Melanoplus differentialis is character-
istic of nearly all grasshoppers, and an account of the manner of laying
and the nature of the soil chosen will illustrate how the danger of an
infestation the following year can be diminished.

Pairing was noticed from the time the grasshoppers reached maturity
in June. Eggs large enough to lay were found, on dissection, during;

Fig. 15. Alfalfa field near Newman with leaves removed by grasshoppers.
Lower parts of poplar trees seen in the background also defoliated by
these insects.

early July, but no grasshoppers were at this time caught in the act of
egg-laying, although there must have been some laying done. None
were found laying before active field observations were discontinued,
about the middle of August, but during the first week in October eggs
were being laid by thousands.

The insect chooses a place in the alfalfa field where vegetation is not
too thick. Bare ditch banks or levees are very suitable places. The
roadside and other bare spots are also acceptable, but more seemed to
be laying in the alfalfa than in other places. In some cases ground was
chosen that was so hard a knife blade could scarcely be forced into it,
but much softer soil was more usual.

On finding an acceptable spot the insect drills a hole from an inch to
an inch and a half long, by means of the four horn-like points on the

STUDIES IN GRASSHOPPER CONTROL.

extreme tip of the abdomen. This hole, as a rule, is not put straight
into the ground, but at an angle. About seventy-five were dug up, and
their relation to the position of the head of the insect noted. Of the
seventy-five only three or four were burrowed straight into the ground.
Only one was found where the curve or angle was toward the head, the
position so commonly figured in grasshopper publications. All the
remainder had a decided backward tilt.

As soon as the hole is drilled deep enough so that nearly the entire
abdomen is buried, the grasshopper ejects a small amount of a frothy
substance into the bottom, and then begins to place the eggs. The

Fig. 16. Poplar trees defoliated by grasshoppers.

species does not seem to have a regular manner of placing the eggs; they
seem to be in a more heterogeneous mass than is the case with most
other species. As soon as enough eggs are laid to fill up as far as the
frothy substance reaches, more of that is ejected into the hole. Then
more eggs are placed, and so on until the hole is filled within half an
inch, or less, of the top. Most of this is filled with this same frothy
substance. Then, with the end of the abdomen, the grasshopper moves
small pieces of dirt around, using the drill as pincers or claspers, until
the hole is entirely concealed; then she walks away.

During the hot part of the day not less than two hours were taken to
drill the hole and deposit the eggs. All the eggs that have reached full
development are placed in the one hole. These in one case numbered 93.

UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION.

Usually, however, there are considerably less, averaging from 60 to 70.
Other layings of eggs are probably deposited later, as an insect killed
just after finishing egg-laying would show that the next lot of eggs in
the oviduct were a quarter or even a third developed.

The frothy substance with which the hole is lined turns in a few hours
into a hard, cement-like substance that seems to be nearly waterproof.
The eggs are thus in what is practically a waterproof capsule. Ordinary
wettings will not affect it, but prolonged soakings may tend to kill
the eggs.

These eggs stay in the capsule, gradually coming to maturity and
giving up the young grasshoppers with the warm days of spring or sum-
mer. As long as the egg capsule remains in an unbroken condition the
eggs are pretty well protected; but if by some means it can be broken,
there is a good possibility of the eggs being destroyed during the winter.

Fig. 17. Wild gourd attacked on one side by migrating swarm of grasshoppers.

In certain experiments in Kansas a number of years ago, with which
the writer was conversant, it was found that the use of circular and
cut-away disks was very successful in breaking up these capsules; and
it was observed, furthermore, that instead of injuring the alfalfa, the
yield of the alfalfa was actually increased, in some cases to the extent
of a ton and a half to the acre. This increased yield after disking
accords with the experience of many California growers, who regularly
disk their fields each fall. The practice is to be particularly recom-
mended wherever grasshoppers have deposited eggs. The blades of the
disk should be set rather straight, so as not to tear out the crown of the
alfalfa root. The ground can be gone over twice, so as to checkerboard
the entire field. In the portion of the field next to the fence, where grass-
hoppers often lay large quantities of eggs, the disks should be run twice
in opposite directions, and almost as good results can be obtained as by
crossing. For a hard soil, the cut-away disk is the better; in ordinary
loose soil, the circular is equally as satisfactory.

STUDIES IN GRASSHOPPER CONTROL. 23

RESUME.

This bulletin records the experience of a successful campaign for the
practical control of grasshoppers. Brief accounts are given of the
" long-legged grasshopper," the "pale-winged grasshopper," the "devas-
tating grasshopper," Hesperotettix sp., and more detailed data con-
cerning the two most distinctive forms. The " valley grasshopper" was
destroyed quite effectively by burning; and, where this was not prac-
tical or efficient, by the use of poison in orchards and vineyards
and by the use of the hopper dozer in alfalfa fields. The method of
constructing a dozer is given, and suggestions as to its use. The
"differential grasshopper" of the Newman district was found easily
controllable by the use of the dozer; and no other methods seemed
desirable under the conditions obtaining there, except the use of the
disk in fields stocked with eggs.

CALIFORNIA PUBLICATIONS AVAILABLE FOR DISTRIBUTION.

REPORTS.

1896. Report of the Viticultural Work during the seasons 1887-93, with data

regarding the Vintages of 1894-95.
3897. Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to

Viticultural Report for 1896.
1898. Partial Report of Work of Agricultural Experiment Station for the years

1895-96 and 1896-97.
1900. Report of the Agricultural Experiment Station for the year 1897-98.

1902. Report of the Agricultural Experiment Station for 1898-1901.

1903. Report of the Agricultural Experiment Station for 1901-1903.

1904. Twenty-second Report of the Agricultural Experiment Station for 1903-1904.

BULLETINS.

Endurance of Drought in Soils of the Arid Region.

Report of the Condition of Olive Culture in California.

The Phylloxera of the Vine.

Feeding of Farm Animals.

Tolerance of Alkali by Various Cultures.

The Potato- Worm in California.

Pickling Ripe and Green Olives.

Citrus Fruit Culture.

Orange and Lemon Rot.

Lands of the Colorado Delta in Salton Basin, and Supplement.

Deciduous Fruits at Paso Robles.

Grasshoppers in California.

California Peach-Tree Borer.

The Peach-Worm.

The Red Spider of Citrus Trees.

New Methods of Grafting and Budding Vines.

Culture Work of the Substations.

Resistant Vines and their Hybrids.

California Sugar Industry.

The Value of Oak Leaves for Forage.

Arsenical Insecticides.

Fumigation Dosage.

Spraying with Distillates.

Sulfur Sprays for Red Spider.

Directions for Spraying for the Codling-Moth.

Fowl Cholera.

Commercial Fertilizers.

California Olive Oil ; its Manufacture.

Contribution to the Study of Fermentation.

The Hop Aphis.

Tuberculosis in Fowls.

Commercial Fertilizers.

Pear Scab.

Poultry Feeding and Proprietary Foods.

Asparagus and Asparagus Rust in California.

Spraying for Scale Insects.

Manufacture of Dry Wines in Hot Countries.

Observations on Some Vine Diseases in Sonoma County. „

Tolerance of the Sugar Beet for Alkali.

CIRCULARS.

No. 1. Texas Fever. No. 10. Reading Course in Economic

2. Blackleg. Entomology.

3. Hog Cholera. 11. Fumigation Practice.

4. Anthrax. 12. Silk Culture.

5. Contagious Abortion in Cows. 13. The Culture of the Sugar Beet.
7. Remedies for Insects. 14. Practical Suggestions for Cod-
9. Asparagus Rust. ling-Moth Control in the

Pajaro Valley.

Copies may be had by application to the Director of the Experiment
Station, Berkeley, California.