WiREWORMS. 79 



1. Destruction of Wireworms by Starvation. 

 a. Starvation hy Clean Falloio. 



It has been the general belief that the wireworms which infest 

 our fields could live but a short time in soil in which no vegetation 

 was allowed to grow. No experiments were recorded, however, to 

 show how lono^ the worms could live in such soiL 



We kept several experiment cages in '^ clean fallow^" for nearly a 

 year, and more w^ireworms remained alive (many of tliem passed 

 through the transformations to the beetle stage) in these cages than 

 in similar cages in which grass was kept growing. Therefore, we 

 would not advise the farmer to lose the use of his land for a season 

 and the labor necessary to keep it free from all vegetation in the 

 hope that he may thus starve out the wireworms. 



1). Starvation hy the Growth of Supposed Iramione Crops. 



It is supposed there are certain crops so distastef al to wireworms 

 that when these crops are grown the worms will either perish from 

 hunger or leave the field, and thus tlie succeeding crops be spared 

 from the ravages of these pests. The crops usually recommended 

 for starving out the wireworms are buckwheat, mustard and rape. 



buckwheat. 



In this country more attention has been directed to buckwheat as 

 a supposed immune crop than to any other. 



By a series of experiments extending over a period of two years, 

 we proved that wireworms will attack and cut off roots of buck- 

 wheat ; and that they can live for many months and undergo the 

 transformations necessary for the continuance of the species, in soil 

 in which only buckwheat is growing. Therefore as wirew^orms 

 have lived as long and thrived as well in cages of buckwheat as they 

 have in cages of timothy and clover, we cannot regard buckwheat 

 as an immune crop. 



MUSTARD. 



In Europe, mustard has long been regarded as a crop that clears 

 the soil of wireworms by starving them out. We experimented 

 with both the Chinese and brown mustard, and wireworms lived in 

 cages containing no other vegetation but these plants for from one 

 to two years ; we have never been able to keep them alive so long 



