69 



From this table we find that more eggs were laid in pastures ( 84 

 grubs per mile) than in any other crop; that small grain came next 

 with 61 and 62 per mile for fields which had been in oats and wheat 

 respectively ; that fallow land, grown up of course to weeds, largely 

 grasses, was third with 48 grubs to the mile; that clover and corn 

 seemed not far apart in attractiveness to the egg-laying beetles — clover 

 with 30 and corn with 25 grubs to the mile; and that meadow crops 

 (excluding clover) were least sought bj^ the egg-laying beetles — about 

 15 grubs to the mile in fields which had been in such crops when the 

 eggs were laid. 



Additional light is thrown on this subject of a possible choice of 

 crops by May-beetles in which to lay their eggs, by data of quite an- 

 other description obtained in 1912. This was a year of extraordinary 

 injury by white-grubs in several counties of northern Illinois; and 

 a request for information concerning the injury itself and the pre- 

 vious cropping of the infested fields was sent out ( during my absence 

 in Europe) by Mr. Eobert D. Glasgow, then of my office staff. Sixty- 

 three replies to this inquiry were received from farmers in Carroll, 

 Stephenson, Winnebago, and "Whiteside counties. In thirty-five of 

 these, estimates were given of the injury to fields of corn. The total 

 area of these thirty-five fields was 676 acres, an average of 19.3 acres 

 to the field; and the total estimated injury was $8843, an average of 

 $13.08 per acre. Forty-four of the sixty- three fields reported had been 

 injured by white-grubs. Thirty-five of them were in corn when in- 

 jured, six in grass, and three in potatoes. The injury was uniformly 

 reported as continuing thruout the season from May or June to Sep- 

 tember, and it was certain, consequently, that these grubs had hatched 

 from eggs laid in 1911. Of the forty-four injured fields, nineteen were 

 in grass in 1911, nineteen were in oats, three in rye, one in barley, and 

 two in corn. That is, altho 80 percent of the injured fields were in 

 corn in 1912 only 5 percent of them had been in that crop when the 

 parent beetles laid their eggs ; and altho only 14 percent of the injured 

 fields were in grass in 1912, 43 percent of them had been in that crop 

 the preceding year. None of the injured fields was in oats, rye, or 

 barley in 1912, but 52 percent of them had been in those crops in 

 1911. Or, more briefly stated, in 95 percent of the injured fields the 

 eggs had been laid in either small grains or grasses, altho only 14 

 percent of the injury was in fields bearing such crops. 



Turning to the nineteen uninjured fields, on the other hand, I find 

 that fourteen of them were in corn in 1912 and also the same num- 

 ber in 1911, three in grass in both years, one in wheat in both years, 

 one in rye. in 1912, and one in oats in 1911. Or, taking corn, grass, 

 and the small grains separately, the number of uninjured fields in 

 each of these classes was the same in both years. The evidence of the 

 predominance of grasses and small grains over corn and other crops 



