42 N. H. AGR. EXPERIMENT STATION. [Bulletin 151 



Demonstration Work. 



In the summer of 1909 cooperative demonstration experiments were con- 

 ducted at several points in the state. 



In each case a representative of the station had immediate charge of the 

 spraying. The station furnished the apparatus and materials. 



Records were kept by most of the growers where such spraying was done, 

 and from these the benefit or profit of the spraying was estimated. The 

 results were uniformly gratifying, and it is believed that such demonstrations 

 are of much practical value. 



Some of the details of this work are recorded in Bulletin 143, pp. 93-96. 



INVESTIGATIONS UNDER THE ADAMS FUND. 



The Apple Maggot. 



The principal investigation of the current year has been a study of the 

 Apple Maggot, Rhagoletis pomonella, Walsh; or, as often designated, the Rail- 

 road Worm. To this work the station entomologist has given the greater 

 part of his time. In addition a student assistant was employed for several 

 hours each day through the spring months, and two student assistants were 

 employed continuously throughout the summer. 



To carry on the work to better advantage two field stations were established. 

 One of these, near Barrington post office, was maintained during the early 

 part of the summer Later a new station was chosen, about three miles dis- 

 tant, and the student assistant who had been at work at the first station was 

 transferred to the second. The maintenance of these stations greatly assisted 

 in the work, since only in this way could the conditions be secured that were 

 necessary for some of the experiments. 



Gratifying progress has been made in this investigation. It is believed 

 that the knowledge of this pest acquired this summer will be of practical 

 value in formulating means of control. 



A part of the experimental work is practically complete, and in this the data 

 on hand are extensive enough to warrant definite conclusions. These experi- 

 ments do not need to be repeated. 



Another part of the work was along new and untried lines. In this the 

 results need verification and amplification, and it is highly desirable that fur- 

 ther experiments be carried on throughout next season. The nature of this 

 part of the work will be indicated below. Again, certain new and important 

 lines of investigation have been suggested by various features of this year's 

 work, and these should receive attention next year. 



For each of the above, careful preparations have been made, and the pro- 

 posed work is already blocked out. 



A brief summary of the results secured to date is as follows: 



A study of the amount of damage done by the Apple Maggot disclosed the 

 fact that fully 95 per cent, of the orchards of the state are more or less infested. 



Certain varieties are especially susceptible to attack. Others are infested 

 only occasionally. One or two varieties are practically immune. Studies 

 were made of seventy-one varieties of apple in this regard. 



