4 N. H. AGE. EXPERIMENT STATION. [Circular 8 



from these, and spend two or more years in the soil, feeding and 

 growing. When mature they change to the pupal stage. From 

 the latter the adult beetle emerges, soft of body at first and 

 remaining in the soil until it has hardened. 



The injury by white grubs comes about in the same manner 

 as that by the wire worms. The ordinary breeding-place is sod 

 ground, the grubs devouring the grass-roots. When such ground 

 is planted to other crops, many grubs remain the first season 

 and some the second, transferring their attentions to the roots 

 of the planted crops. 



The nature of the damage done by these pests varies with the 

 crop attacked. In potatoes they gnaw shallow cavities in the 

 surface, much as if some small animal had been at work on 

 them. Strawberry plants may be severely injured, the roots 

 being eaten away and the plants killed. Even in sod ground the 

 grubs sometimes become so numerous that the grass is entirely 

 killed out in sections. 



PREVENTING INJURY. 



Either with white grubs or with wireworms it is not feasible 

 to kill off the pests in the soil by applying chemicals. Any 

 known substance that might be used for this purpose would 

 injure the crop if applied in sufficient quantity to put an end to 

 the worms. 



Preventive measures, rather than a cure, are called for. When 

 sod land is broken up for a crop, if it harbors many of the pests 

 which usually is the case it had best be planted at first to 

 some crop not apt to be badly injured. 



None of the clovers, or related plants, such as cowpeas or 

 alfalfa, usually suffer appreciable damage. A mixture of oats 

 and cowpeas makes a resistant crop. Millet is not apt to be 

 damaged, and the same is true of rye. After the first season in 

 one of these crops it is ordinarily safe to follow with a hoed 

 crop, such as potatoes or corn. Cabbages may safely follow sod. 



If sod ground can be plowed late in the fall many of the pests 

 will be turned up, exposed to the winter weather or to birds, and 

 will not survive. Such plowing will be more effective if done late, 

 after the worms have grown sluggish. Chickens given the run 

 of a newly plowed field will find many of the pests. 



Hogs are fond of white grubs, and will root up the soil deeply 

 in" search of them. Advantage may be taken of this fact in 

 ridding a field of the pests. 



Approved : 

 J. C. KENDALL, 



Director Extension Work. 

 DURHAM, N. H., March, 1913. 



