508 Grasses and Leguminous Crops in New York 



Control. White grub injury to grasses may be avoided in large 

 measure by practicing a proper rotation of crops. As previously 

 stated, the grubs do the greatest injury during the season follow- 

 ing that in which the eggs are laid. Observations in Illinois have 

 shown that the beetles prefer to lay their eggs in ground that is 

 well covered with vegetation. Pasture land, wheat, and oats are 

 chosen in the order named. Clover is a relatively immune crop, 

 very few eggs being laid in fields where there is a heavy stand. 

 The measures for preventing white grub injury to grasses are 

 based on the above facts. 



Unfortunately it is not possible to take advantage of the fact 

 that the beetles avoid laying eggs on comparatively clean fields, 

 because experience has shown that as a rule in New York the best 

 results are to be obtained by sowing timothy with clover after 

 wheat. But, since the clover predominates in the first year's 

 seeding, it has a tendency to keep the beetles from choosing such 

 fields for eg'g-laying and thus delays the infestation of the field for 

 a year. This practice of sowing timothy with clover would there- 

 fore appear to be justified from the standpoint of the prevention 

 of white grub injury. In the second year's seeding, however, 

 grasses predominate owing to the fact that most of the clover has 

 been killed by the attacks of the clover root-bOrer. Such fields 

 are then very attractive to the beetles for egg-laying and conse- 

 quently the longer a field is left in grass the more seriouly will 

 it become infested with white grubs. This indicates the impor- 

 tance of adopting a rotation of crops in which fields are not left 

 in grass more than two or at most three years. These measures 

 are in line with the best agricultural practice and if adopted will 

 not only in a large measure prevent white grub injury, but will 

 also encourage the growing of clover, one of the most important 

 factors in successful farming under New York conditions. 



wireworms 



Several species of Elateridae 



The size and value of the grass crop in New York State is 

 annually lessened to a much greater degree than is usually sup- 

 posed by the attacks of wireworms. Wireworms are elongate, 

 hard-shelled, brownish larvse (Fig. 611), the immature stages of 



