Agricultural Research in New Hampshire 33 



a light oil, may prevent the hatching of eggs. In this respect the im- 

 portance of the liquid carrier for a compound, as already indicated in 

 earlier work in this project, is emphasized. 



W. C. O'Kane, J. G. Conklix 



Insect Record 



Work on this project has continued along the lines followed in the 

 past. Scouting in the summer of 1945, in anticipation of a possible out- 

 break of the spruce budworm, revealed the presence of light infesta- 

 tions of this insect in Colebrook, Clarksville, and Pittsburg. No notice- 

 able defoliation has occurred. Preliminary scouting in 1946 indicates 

 that the insect continues to be present in the northern part of the state, 

 but there is still no indication of defoliation in the area examined. 



The Japanese beetle population is apparently building up in Dover, 

 Concord, and Keene. In Concord, sod samples indicated a grub popula- 

 tion averaging between 40 and 50 grubs per square foot. Apparently 

 this insect is reaching the point where noticeable damage to lawns may 

 be expected shortly. 



The fall webworm occurred in outbreak form throughout the state 

 in 1945, 'causing extensive defoliation of shade trees. 



The European corn borer was noticeably abundant in southern New 

 Hampshire in 1945 but for the state as a whole showed a slight decrease 

 over 1944. 



J. G. CONKLIN 



Apple Maggot 



In 1945 a 3 per cent DDT dust was applied to sod beneath apple 

 trees as a possible means of destroying emerging apple maggot flies. This 

 experiment was unsuccessful as a control measure, fruit in the orchard 

 being 100 per cent infested with the apple maggot. \ 



Gesarol AK 40 Spray (40 per cent DDT), at 1.5 pounds per hun- 

 dred gallons, applied in three sprays to control the apple maggot, re- 

 sulted in the production of fruit 97 per cent free of apple maggot injury. 

 This was comparable to control obtained with two applications of lead 

 arsenate at three pounds per 100 gallons. 



J. G. Conklin, W. C. O'Kane 



Studies of Insects Affecting Spruce 



The present outbreak of the spruce budworm in Canada and its 

 spread into northern New York state and parts of Maine is a matter of 

 concern to all timber-land operators in northern New Hampshire. Scout- 

 ing of selected spruce-fir areas, in 1945, revealed the presence of light in- 

 festations of the spruce budworm in the extreme northern part of the 

 state. 



In order to obtain a check on the possible increase of the spruce bud- 

 worm in New Hampshire, a series of permanent plots was established in 

 June, 1946, and should give a means of measuring the budworm popula- 

 tion throughout our spruce-fir areas. 



