6 N. H. AGRI. EXPERIMENT STATION [Bulletin 247 



long, were alternated in the holes with dominant leaders, one-half inch 

 in tip diameter and thirteen inches long. Fifty weevils were liberated 

 on the floor of the cage. 



Two days later, June 27, 1927, thirteen weevils were found on the re- 

 cessive leaders and twenty on the dominant leaders. June 28 the exper- 

 iment was repeated with different weevils and fresh leaders. This time 

 the leaders were arranged alternately as before, but in reverse order. 

 After two days twelve weevils were taken from the recessive and twenty- 

 six from the dominant leaders. 



The experiments confirm field observations, which show that the weev- 

 il prefers the large and dominant to the small and recessive leader. 



In numerous instances it has been noticed that certain trees, which 

 from their vigorous growth would appear susceptible to weevil attack, 

 are not injured, while others in the immediate vicinity, which would ap- 

 pear less susceptible, are attacked. To a certain extent infestation may 

 be based on chance. 



HOST TREES 



The white pine weevil feeds principally on white pine. Although 

 workers have reported this insect as damaging other species of conifers, 

 such infestation is not economically important. Nonvay spruce is prob- 

 ably the next most susceptible host. 



Hopkins (1911) listed as hosts jack pine, Piniis Banksiana; pitch pine, 

 Pinus rigida; and red spruce, Picea rubra. Peirson (1922) observed or 

 verified Japanese pine, Pinus densiflora; Scotch pine, Pinus sylvestris; 

 and Norway spruce, Picea abies. Currie (1905) lists deodar or Himalay- 

 an cedar, Cedrus deodara. Packard (1890) mentions balsam fir, Abies 

 balsamea; and hemh-.'k, Tsuga canadensis. In the course of this study 

 in New Hampshire the weevil has occasionally been found on Scotch 

 . pine, pitch pife. red pine, and Norway spruce. 



No doubt some of the earlier writere confused the white pine weevil 

 with other species in the same genus. Probably Currie (1905) and Pack- 

 ard (1890) erred in this respect. Further, it is possible to find an acci- 

 dental specimen on some species of conifer other than white pine, al- 

 though breeding may not take place on the trees noted. 



June 21, 1927, several white pine weevils were noted copulating and 

 feeding on the leaders of two Norway spruce trees about eight years old, 

 located in Barrington, N. H. They made a large number of feeding 

 punctures. On either side of the row in which these two trees stood 

 were other rows of mixed and pure white pine, red pine, and Scotch pine, 

 15 to 20 feet high. These trees were from 15 to 100 feet away. In these 

 rows no weevils were found on any other species than white pine. 



At the time of the first observation noted above the weevils on the 

 two Norway spruces were allowed to remain there in order to determine 

 the extent of injury. Two months later the leaders exhibited no evidence 

 ■of larval tunnels and no signs of injury other than the feeding punctures 



