THE OKTIIOPTEKA OF MINNESOTA. L'.-i 



rather the young locusts hatched are prevented from reach- 

 ing the surface. The best time to plow the fields is the 

 autumn, as by doint^ so the surface of the plowed fields be- 

 comes hardened by the rains and snows of winter, and the 

 egg-pods and single eggs are thoroughly surrounded by 

 earth washed around them. Early in spring is also a good 

 time, providing the plowing is followed b\' the usual spring 

 sliowers. But even if no rain should follow the plowing the 

 more or less violent winds of spring will smooth and make 

 the soil compact, sufiiciently so to prevent the great ma- 

 jority of young locusts from reaching the surface. Of course 

 the plowing must be done thoroughly; simply scratching 

 the surface of the infested field is of but slight use, though 

 even then many egg-pods are torn to pieces and numerous 

 of the now unprotected eggs are destroyed. 



If large fields are thus plowed we secure another advantage: 

 in case locusts should reach the surface the}' find no food, 

 and before the\^ can walk to other fields covered with 

 plants, they starve. 



Plowing is an excellent remed\' even after the locusts have 

 hatched and reached the surface. In such a case plowing 

 should commence at the outer edge of a field, and a number 

 of plows should be used at the same time, the plows follow- 

 ing each other as closely as possible. The locusts are in 

 this manner forced towards the center of the field, where a 

 black mass of struggling insects is crowded together. But 

 few of them escape; as one plow makes a furrow, this is 

 rapidly filled with locusts, the following plow covers them 

 up, and most are buried alive; those that escape this fate 

 have to starve, and only a few near the edges of the field 

 can save their lives. 



Burning. — In many places, where the eggs are not numer- 

 ous enough to warrant plowing, all the old stubble and dead 

 grass, etc., should be preserved until the locusts hatch. 

 After plowing around such fields to prevent the escape 

 of the fire, the enclosed space can be burned over 



