CONDITIONS AFFECTING SPREAD 23 
jola a certain number of the grasshoppers, for these insects 
are sluggish in the extreme and might, in all probability, 
be carried many miles in a cart without becoming in the 
least disturbed. 
This probably happens comparatively rarely, other- 
wise the spread of the pest would have been much more 
rapid and general than it has been. It may frequently 
happen that the number so transported is too small 
for the grasshoppers to make a start im the new 
territory, for they might all be destroyed by various natural 
enemies or die from other causes before they reach matu- 
rity and are able to lay eggs. In any case, this possible 
means of spread is a matter of considerable importance, 
and the knowledge of its possibility should be widely 
spread, so that precautions may be taken to guard against 
it as far as possible in the future. 
With regard to the gradual spread within the terri- 
tories already infested, some important observations have 
been made. It has already been noted that, up to the 
present, crops grown on black cotton soil have suffered 
most; at least that is the case in Mysore. <A possible 
reason for this has already been suggested. During the 
summer of 1910 there was, however, a marked tendency 
in some localities for the grasshopper to spread in num- 
bers on to the red soil tracts, and it is probably only a 
question of a year or so when these will be almost as 
badly infested as the black soil tracts. 
Streams are among the most efficient checks to the 
spread of the pest. A good example of this was found in 
the infested villages, Marikoppa, Hattur, Dodyarehalli 
and Madenhalli, west of Honnali, just north of the 
Honnali-Shikarpur road. The infested lands of these 
villages lie between two streams which run almost parallel 
to each other and empty into the Tungabhadra just 
below (north of) Honnali. The worst affected portion 1s 
the strip of black cotton soil which lies midway between 
the two streams. From the middle, this soil shades off on 
either side towards the streams into a red, more or less 
sandy loam where the pest was not so serious but was 
nevertheless present. The two banks of the more southerly 
stream were followed and examined for a distance of 
between two and three miles and it was found that, on 
the northern bank, the grasshoppers could be found im 
