"ملف ٣٧/١٦أ- I تدابير مكافحة الجراد الصحراوي" [و‎‎٢‎٢‎٩] (٩٠٠/٤٥٧)

5
of rewards graduated according to distance from habitation, with a wide
discretion to the District Officer, is worth consideration.
Control measures at breeding grounds.—(1) When a breeding ground
is located, the first step is to ring it by a method suitable to the soil
(Method 2, Appendix).
(2) The actual nlethod used will depend on the nature of the soil:
generally trenching is the simplest and cheapest. It is important that the
jg* work shall be thoroughly done, hence payment for supervision and any
essential labour would be fully justified. It is important that breeding
grounds in remote places or on difficult soil should not be neglected.
Egg destruction. —Where a breeding ground has been properly ringed,
no rewards for egg destruction are necessary. But any breeding ground
which, for any reason, it is not possible to ring should be dealt with by the
destruction of the eggs, on an organized system. Ploughing is ineffective,
flooding is of limited application and must be protracted. The digging out
and destruction of the egg-masses is effective—so far as it goes—but always
leaves behind a large number of eggs to produce hoppers.
Cultivated plots within a ringed breeding ground. —When a ringed
area iucludes crops or other vegetation, there are two problems :—
(а) To ensure that hoppers do not find sufficient food within the ringed
area to enable them to leave eventually as fliers, and
(б) To protect the crops.
The first danger can largely be met by subsidiary ringing (Method
2, Appendix) or by any of the other means recommended for
hopper destruction [Methods 3, 3 (a) or 3 (6), Appendix].
(c) Crops can be protected by individual trenches surrounding the
fields, the construction of which should be the duty of the
cultivators themselves—but under proper supervision.
Hoppers. —The total length of the hopper period varies greatly but
may be put at four to eight weeks according to the food supply and climatic
conditions. Control measures are far more effective against young hoppers
before the second moult than subsequently and also much easier.
Methods for the destruction of hoppers may be either chemical or
mechanical.
Chemical Methods.—Contact insecticides— as distinct from stomach
insecticides.
Many satisfactory, though expensive, contact insecticides are known,
but their use on a wide scale in India is not immediately practicable. (See,
however, for their use in special circumstances Method 3, Appendix.)
Stomach insecticides (which act through being eaten).
(a) Baits.—Of these the most applicable to Indian conditions is sodium
fluosilicate which is deadly to locusts but has been shown by actual experi
ments in India to be innocuous to domestic animals—even in far larger
doses than could possibly be consumed by a grazing animal. Locusts will