WiRBWORMS. 83 



also be very destructive to vegetation. Although a valuable fer- 

 tilizer, it is too expensive an insecticide to use against wireworms. 



LIME. 



Lime has long been used as a fertilizer, and many report good 

 results from its use on fields infested by wireworms. However, our 

 experiments covering a period of over seven months showed that 

 lime applied at the rate of even 200 bushels per acre, either slaked 

 or unslaked, or as lime water, had no effect upon the wireworms. 



CHLORIDE OF LIME. 



Several experiments made with this substance showed that it will 

 kill wireworms in the soil, but must be used at the rate of nearly 

 six tons per acre. It is thus impracticable and too expensive. 



GAS LIME. 



This is the refuse lime thrown out at gas works. When fresh it 

 smells strongly of ammonia and sulphur, but becomes nearly 

 odorless after exposure to the air for a few days. We thoroughly 

 tested it ; and our experiments indicate that the killing properties 

 of the gas lime soon pass away, and it has to be used fresh in 

 such great quantities (twenty to forty tons per acre) to be even 

 partially effective that, notwithetanding its cheapness, it is hardly 

 practicable on large areas. 



C. DESTRUCTION OF PUP^ AND ADULTS. 

 (CLICK-BEETLES). 



1. Fall Plowing. 



It is with pleasure that we turn from the discussion of measures 

 that give little or no promise of practical use to one that we 

 believe is of great importance. For the results of our experiments 

 convince us that much can be done towards checking the increase 

 of wireworms by fall plowing. 



The explanation of the beneficial results that will follow fall 

 plowing we believe to be found in the following facts, which were 

 brought out in our studies of the life history of our more common 

 species of wireworms : Wirewonns live for at least three years in 

 the worm or larval state. In this state they cease feeding about 



