118 Report of Farmers' Institutes 



generations were reproduced, but from the first-born descendants 

 four generations resulted. Computations based on these data show 

 a possible rate of multiplication in a year of approximately 35,- 

 000,000 to one for the year, under optimum conditions — a ratio 

 of increase only about 1/100 as great as that of some other investi- 

 gators who failed to consider the smaller number of generations 

 from late-born scales in a series. 



Spraying experiments with various preparations of lime and 

 sulphur, and with two miscible oils, justify the usual preference 

 for the sulphur compounds, owing to their prolonged effect in 

 spring spraying. Home-made preparations were as effective as 

 commercial. Early spraying, before the orchard is seriously in- 

 fested, is of marked advantage, and spring treatment superior to 

 fall spraying. That badly infested orchards may be redeemed 

 and maintained in good condition with one or two sprayings a 

 year was proven by the tests. 



Potato insects (Iowa 155). — This is a comprehensive discus- 

 sion in 64 pages, well illustrated, of the insects affecting the 

 potato plant. In several cases charts are given showing the rela- 

 tion of the life cycle of the insect to the growth of the plant, thus 

 making clearer the proper time for treatment. 



Diseases of the sweet pea (Del. 106). This is a very compre- 

 hensive discussion of nearly a dozen sweet pea affections, rather 

 scantily illustrated. Boiling seeds for one to two seconds, soak- 

 ing in sulphuric acid, or soaking in formalin, aid in controlling 

 some of the diseases, but watering the soils with chemical poisons 

 does not increase the resistance of plants grown on that soil. 



RURAL economics 



Cost of producing Minnesota field crops (Minn. 145). This 

 bulletin is of interest in New York mainly through its presenta- 

 tion of methods and discussion of the cost factors involved in crop 

 production, with the effect upon these of changes in conditions. 



Cost of production on Missouri farms (Mo. 125). Another 

 excellent presentation of the methods and factors of cogjt account- 

 ing. 



Cooperation among farmers in Minnesota (Minn. 146). Min- 

 nesota leads the states of the Union in the number of cooperative 



