462 MAINE AGRICULTURAL, EXPERIMENT STATION. 19.12. 



worms were abundant in the field especially about the roots of 

 the corn plants, though apparently not as numerous as in 1911. 

 The difficulty in conducting field 'experiments of this kind is 

 the practical impossibility of having reliable checks which can 

 be tested quantitatively, owing to the numerous uncontroll- 

 able factors. Whether the cultivation of the field during the 

 2 years was the cause of the apparent reduction of the wire 

 worms or whether the weather conditions were most concerned 

 we have no means of knowing. 



There was nothing, however, in the experiments in 1912 to 

 invalidate the conviction that continued cultivation and rota- 

 tion of crops will in the course of several seasons materially 

 reduce the wire worms in an infested field. Certain it is that 

 sod land is always more heavily infested than fields long in 

 cultivation. At Guilford, Maine, a place of worn out sod land 

 newly planted to potatoes produced plants that looked at first 

 glance like those affected with "black leg." Examination showed 

 stems and tubers cnewed by wire worms which were seen in 

 situ. 



A more satisfactory method of testing the food preferences 

 of wire worms would probably be to introduce a sufficient num- 

 ber of larvae of a known species into pots of the plants to be 

 tested with suitable checks for comparison. 



Most of the larvae found at Highmoor in 1911 were Agriotes 

 manciis. In 1912 over 99% of the larvae examined belonged 

 to this species. On August 7 while digging for larvae several 

 adults of this species, evidently recently transformed, as well as 

 pupae were found. 



This species which in the middle west is known as the Wheat 

 wire worm because of its depredations upon Wheat is also a 

 pest there to Indian corn. The adult insect probably lays her 

 eggs near the roots of grasses and the young hatching there- 

 from are supposed to require 3 years to complete the life cycle. 

 The larva transforms to the pupa late in July early in 

 August. The adults emerge from the ground ; L ^r June. 



There is reason for believing that the H- T ~ansform 



into adults and that they hibernate tindery j s form, 



and not as pupa. 



