282 STATE BOARD OF AGRICULTURE. 



added to tlie list already on liand. There is also evidence that the 

 Avork of these parasites in some restricted area has been effective enough 

 to be distinctly felt, altlionfili not snfficient 1o warrant even considering 

 a change in our sjiraA^ing policy. 



Our attempts to introduce the European parasite of the Tamarack 

 Saw-fly have api)arently failed and the attempt is to be discontinued 

 until we are able to secure more nmterial from Europe. 



An attem])t 1o locate the cause of injury to peaches in southwestern 

 Michigan led to some measure of success, although much remains to be 

 done in devising means to control the pest. 



A new project was started in the spring to determine the compara- 

 tive insulating values of several of the more commonly emploj^ed sub- 

 stances as fillers in double walled bee-hives. These substances are being 

 tested by Mr. G. C. Woodiu in comparison with dead air spaces and 

 with each other, at the request of some of those interested in the 

 manufacture of bee-keepers supplies. 



Dr. G. D. Shafer, with the publication of Technical Bulletin No. 21 

 on ''How Insecticides Kill," has discontinued active work on that project, 

 (4b) and has started work on project (4:C), a study of the factors which 

 govern mating in the honey-bee. The preliminary work on this project 

 is progressing favorably. 



Many insect pests have been received and reared in the course of the 

 year. 



Eespectfully submitted, 



R. H. PETTIT, 

 Entomologist of Experiment Station. 

 East Lansing, Mich., June 30, 1916. 



REPORT OF THE HORTICULTURIST. 



Director R. S. Shaw: 



Dear Sir — I herewith submit the report of the work in Horticulture 

 for the year ending June 30, 191G. 



Much of the horticultural work has consisted of a continuation of 

 the experiments referred to in previous reports although this work has 

 been considerably increased due to the addition of another member to 

 the Experiment Station force during the past year. Mr. H. J. Bock 

 was employed January 1, 1916, as an experimental assistant in horti- 

 culture to work particularly on the subject of bud variation and selec- 

 tion and has also undertaken other lines of experimental work in 

 pomology. 



Of the experiments previously reported, those upon spraying have 

 been considerably enlarged upon due particularly to increased facilities 

 for performing these experiments and to the increased demand for work 

 along these lines. At the present time, in addition to the spraying ex- 

 periments on fruits and potatoes that are being carried on at this place, 

 we are making rather extensive spraying experiments Avith the various 

 dust sprays now being recommendecl by some commercial concerns, 

 particularly at the Strange orchard at Grand Ledge an<| at George 



