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Full text of "Control of grasshoppers in the prairie provinces."

AGRICULTURE CANADA 



SPECIAL PAMPHLET 



-7JUIL1S81 



No. 36 



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WAR-TIME 
PRODUCTION 




AGRICULTURAL 

SUPPLIES 

BOARD 

OTTAWA CANADA "•? 




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CONTROL OF GRASSHOPPERS IN THE 
PRAIRIE PROVINCES 

The most troublesome grasshoppers of the prairies are the lesser migratory 
or stubble grasshopper, the clear-winged or roadside grasshopper, the two-striped 
grasshopper, Packard's grasshopper, and several species of range grasshoppers of 
which the big-headed grasshopper is the most injurious. 

All injurious Prairie grasshoppers pass the winter in the egg stage. The eggs 
are found to a depth of H inch below the ground surface and are packed together 
in pods which vary in size. For example, the lesser migratory grasshopper 
commonly lays up to 28 eggs in a pod but under very dry conditions the pods 
may contain as few as 2 to 3 eggs. The big-headed grasshopper averages 
about 7 eggs to a pod, while pods of the two-striped grasshopper commonly 
contain over 60 eggs. The eggs do not begin to hatch until the soil becomes 
warm, usually about the time the poplars come into leaf. 

Some non-economic species of grasshoppers overwinter as partially grow r n 
nymphs. Their presence gives rise to frequent erroneous reports that the 
injurious grasshoppers are hatching, and to the hope that subsequent frosts will 
surely kill them. 

Control 

The key to success in any control campaign is whole-hearted co-operation 
on the part of everyone concerned. 

The increase in numbers of grasshoppers is associated with periods of scanty 
rainfall and high temperature, and with cultivation and overgrazing. Hence 
modifications of tillage and grazing practices, to provide conditions less favour- 
able for grasshopper survival and reproduction, are an essential part of control. 
With climate and local agricultural practices varying in different sections of the 
park-belt, open prairie, and range land, it is impossible to recommend practices 
which will be universally applicable. However, the following recommendations 
have been thoroughly tested and have proved successful in regions to which they 
are adapted. In applying these control methods one must also keep clearly in 
mind the type and severity of the infestation with which one is dealing. From 
the practical standpoint, the most important consideration is whether the grass- 
hopper eggs occur throughout stubble fields, including lands intended for seeding, 
or whether they occur chiefly outside of crop land. In the latter case they may 
be concentrated in egg beds on the roadside, headlands, range land, or in weedy 
patches, drift soil, and along ditch banks. 

-hod by Authority of Honourable J. G. Gardiner, Minister of Agriculture, Ottawa, 1940. 
10— 50M— 3703— 2:40 



To be most effective and most economical of time and resources, the control 
program must include: (1) careful planning of the whole operation of the farm; 
(2) the sound use of tillage; (3) careful range management; and (4) the proper 
use of poisoned bait. 

1. Farm Planning 

Careful planning is essential to best control. This is particularly important 
in the areas of open plains, where widespread infestations of the lesser migratory 
grasshopper are likely to be found. The work should be so timed that summer- 
fallows will be completed before the grasshoppers migrate from the stubble to 
adjacent crops. As much as possible of the infested stubble land and recently 
abandoned land, which may be heavily infested, should be summer-fallowed and 
than by seeding a larger, improperly prepared acreage. 

worked in a manner that will destroy the grasshoppers or their eggs and prevent 
migration. In severely infested areas it is folly to "stubble-in" any crop. Seed 
only summer-fallow and other fields which were worked the previous autumn or 
vers- early in the spring. By following this plan, a greater return will be assured 
than by seeding a larger, improperly prepared acreage. 

2. Tillage 

The proper use of tillage implements, particularly in areas infested by the 
lesser migratory grasshopper, greatly increases the possibility of effective control 
with only slight, if any, additional expense. 

(a) Mouldboard ploughing to a depth of 5 inches is an excellent method of 
destroying grasshopper eggs, provided there is sufficient moisture to permit a 
good job of ploughing. It is best done in the autumn but may also be done in 
the early spring if the land is packed. This method is applicable in a large 
section of Manitoba and the park-belt, but in the open prairie there are area? 
where the mouldboard plough cannot be used and other areas where ploughing 
has given way to "ploughless cultivation." The disc plough is only partially 
effective. 

(b) Early fall tillage, preferably behind the binder, prevents further egg- 
laying by grasshoppers. 

(c) Shallow cultivation of infested stubble with the duck-foot cultivator, 
or single disc, has given excellent results in some districts. The most effective 
work is done with a single disc set to cut no deeper than 2 inches and drawn 
with a tractor at a speed of at least 4^ miles per hour. This throws the soil and 
leaves many of the eggs on the surface, where they perish. The operation is 
more effective if done in the autumn and gives reasonable control of moderate 
infestations, but with severe infestations the treatment is well worth while 
as it reduces the infestation of the following summer. This practice is most 
effective in Alberta and western Saskatchewan, where the snowfall is light. 
It is sometimes of value in Manitoba, but cannot be depended upon. 

(d) Guard strips of a black unseeded strip, a rod wide, around the outside 
of cropped fields will help to check invasion of young hoppers from summer- 
fallow and reverted fields until the hoppers can be killed with poisons. They 
are also of some value in protecting fields from invasion by a roadside infestation. 

(e) Summer- fallow. Proper summer-fallowing is the most important 
cultural practice in controlling grasshopper outbreaks, particularly with the 
stubble type of infestation. Young grasshoppers migrating out of improperly 
worked summer-fallow may seriously damage adjacent crops. Since the grass- 
hoppers <m such fields can be poisoned readily without additional time or cost 
for tillage, handling summer-fallow as described below and illustrated in the 
accompanying diagram should be adopted as an annual practice in prairie 
districts. 



Diagram of Field to be Summer-fallowed taken from "Grasshopper Control in 
Saskatchewan", Bulletin 87. 



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Figure "A" 



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Figure "B" 



Diagram of Field to be Summer-fallowed 
Illustrating essential features of how the plan for preventing migration of hoppers from 
summer-fallow to crop may be worked out. Figure "A" illustrates a field worked in lands. 
Figure "B" illustrates a field worked around and around, beginning at the outside. 

Make a "black" guard strip not less than 3 rods wide around the outside of 
the field. Work down the remainder of the field in lands, leaving weedy trap 
strips in the centre of each land, where the young hoppers will gather for green 
food. If the field is not to be divided into lands but is worked as one piece from 
the outside toward the centre, one continuous trap strip should be left around the 
entire field, about 4 rods in from the margin. At least one more trap strip should 
be left in the centre of the field. In all cases the trap strips should be one to 
three rods wide, depending on the infestation. If these are too narrow, tin- 
hoppers may move off before they can be poisoned. Bait each trap strip 
promptly as the hoppers gather in it, and repeat whenever necessary. Under 
strip-farming conditions, the strips should be handled in a similar manner 
except that both guard and trap strips will be only about one rod in width. 

3. Range Management 

Any arrangement whereby portions of the range are kept free from stock 
during the growing period of the grasses, will have a beneficial and lasting effect 
on the range conditions. This will help greatly to restrict the grasshopper 
breeding grounds, which may then be kept under control by annual poisoning 
so that the grasshoppers are not allowed to reach injurious numbers. 

4. Baiting 

Poisoned bait, when properly used, is the most effective and practical means 
of killing both young and adult grasshoppers. It is the only means of controlling 
infestations in sod such as occur along roadsides, field margins, sloughs, pastures 
and open ranges, where cultural practices cannot be used. It should be used in 
field margins where grasshoppers are invading the crop, and to destroy concen- 
trations of hoppers in trap strips. Poisoned bait is also effective in controlling 
general field infestations when used in conjunction with proper cultural methods. 



Bait is distributed by the Provincial Departments of Agriculture in co- 
operation with the municipalities. The individual farmer, therefore, is not 
concerned with the bait formulae or instructions for mixing, which are given out 
to the mixing station operators. Formulae vary somewhat according to the area 
and species concerned and the availability of supplies. 

In order to be most effective, poisoned bait must be spread according to the 
following directions: — 

(a) Spread bait at the right temperature. Grasshoppers are not very active 
until the temperature reaches 65 degrees in the shade. They are most active 
between 75 and 90 degrees. The best kills are obtained if bait is spread when 
a rising temperature first reaches 68 degrees (in the shade) on calm, sunny 
days. One of the best guides is to watch the grasshoppers and spread bait 
as soon as they begin to feed. The moisture in the bait is. very attractive, 
and if the bait is spread when they are not feeding it loses its attractiveness 
very quickly by drying out. Particularly good kills are secured when hoppers 
first start feeding after several days of cool, cloudy or rainy weather. 

(6) Spread bait thinly. Do not exceed 20 pounds to the acre even where 
grasshoppers are very abundant in rank vegetation. Larger quantities are 
dangerous to stock, are wasteful, and decrease the efficiency. Five pounds to 
the acre gives very satisfactory results. Bait should be spread only where grass- 
hoppers are present. 

(c) Spread bait by hand on land that is too rough for a mechanical spreader 
and on small, isolated egg beds of the clear-winged grasshopper. Under such 
conditions hand spreading is considered very efficient, and even in infestations 
of larger areas no farmer should delay spreading to wait for a mechanical 
spreader. 

(d) Spread bait with mechanical spreaders wherever they are available 
and the contour of the land and the absence of bush permit, and particularly 
where the infestation covers a large area. A perfectly working mechanical 
spreader will cover more ground with less bait than can be clone by hand. 

(e) Spread bait as soon as hoppers begin to appear in numbers, to prevent 
crop loss. 

(/) Continue to spread bait throughout the summer whenever and wherever 
grasshoppers are present in numbers. This will reduce subsequent infestations 
as well as reduce immediate crop loss. This can be done to particular advantage 
with the clear-winged and two-striped grasshoppers when concentrated on egg 
beds on the roadsides and headlands, and with other species congregating in 
late iireen crops. 

Much can be done to prevent a grasshopper outbreak by keeping close 
watch for any concentration of hoppers and poisoning them before they com- 
mence to cause damage, and by adopting as a regular practice those tillage 
operations which are known to reduce grasshopper populations 

Further information may be obtained by writing to the Dominion Ento- 
mological Laboratory, at Brandon, Man., Saskatoon, Sask., or Lethbridge, 
Alta.; or to the Provincial Department of Agriculture, at Winnipeg Man' 
Regina, Sask., or Edmonton, Alta. 



Prepared byjl. D Bird Brandon. Manitoba, m consultation with H. L. Seamans, Lethbridge 
Alberta, and K. M. King, Saskatoon. Saskatchewan. Division of Entomology Science 
Service. Department of Agriculture, Ottawa. Canada. 

Ottawa: Printed by J. O. Patbnaum, I.B.O., Printer to the King'* Most Excellent Majesty, 1940.