EXPERIMENT STATION REPORTS. 187 



ever, the dates obtained last summer by this method seemed to be fairly cor- 

 rect and the attempt is being repeated along the same lines this year. The 

 following deserve the gratitude and thanks of all concerned because of the 

 work and care made necessary by their voluntarily acting as observers: 

 Mr. Stanley Johnston, South Haven Experiment Station, Van Buren County; 

 Mr. J. O. Hain, Cassopolis, Cass County; Miss Addie Sly, Birmingham, 

 Oakland County; Mr. Minard E. Farley, Albion, Calhoun County; Mr. L. H. 

 Kirkland, Erie, Monroe County; Mr. W. A. Chapman, Bangor, Van Buren 

 County; Dr. Huston, Traverse City, Grand Traverse County; Mr. Frank 

 Smith, Hart, Oceana County; Dr. F. L. Simanton, St. Joseph, Berrien County; 

 Mr. Don Hootman, Graham Experiment Station, Grand Rapids, Kent 

 County; Mr. Walter Wightman, Fennville, Allegan County; Mr. Edward 

 Lj^man, Kibble, Van Buren County; Entomology department, East Lansing, 

 Michigan. 



Borer repellant. — For about a century now, fruit growers and entomologists 

 have been in search of something that will repel borers and protect fruit trees 

 more especially, but really all trees as well. Thus far, results have been 

 disappointing but the object to be finally attained warrants the expenditure 

 of much effort even if most of it is wasted. During the season of 1920 a test 

 was made of a new mixture with a hundred or so trees, and during that time 

 our coating seems to have afforded ciuite a measure of protection. The 

 present season seems to promise equally good results and we are hoping to 

 at least produce something that will protect j^oung orchards from the dreaded 

 flatheaded apple-tree borer. 



Greenhouse pests. — The direct control of greenhouse pests has progressed 

 somewhat during the season. Quite a bit of effort has been expended on 

 Aleyrodes and on some of the scale insects with a measure of success. 



Household insects.— The work on these pests has been practically at a stand 

 still during the present season. Not for lack of effort but because measures 

 from which we had hoped much, seem to be inadequate. I refer to the control 

 of clothes-moths and carjjet-beetles. 



Mill insects. — Heat treatments were carried on wherever opportunity 

 offered and usually with gratifying results. 



Canker worms. — For two seasons the canker worm has played havoc with 

 our apple orchards especially in the eastern part of the State. Many of the 

 smaller orchards, whose owners are not primarily interested in apples, are 

 being killed out owing to delay in spraying or failure to spray at all. 



An enemy of blue spruce, Olethrentes abieiana has recently been received 

 from Ludington, Michigan, where the small caterpillars are devouring the 

 leaves. 



It is difficult to control owing to the close webbing of the twigs inside of 

 which webbed masses the caterpillars feed. The difficulty seems to be that 

 of reaching the creatures with arsenate of lead rather than anything else. 



Rcspectfullv submitted, 



II. H. PETTIT, 



Entomologist. 



East Lansing, IMichigan, Jmie 30, 192L 



