28 MAINE AGRICULTURAL EXPERIMENT STATION. I912. 



est amount of injury obtained under the conditions of 191 1, it 

 is seen that from the commercial standpoint the injury is alto- 

 gether negligible in comparison with the advantages of annual 

 crops of clean, worm-free fruit. Spray applications must, of 

 course, be made at fairly definite, and in some instances at 

 very definite, periods of the season. At times of unsettled 

 weather or during very hot periods the orchardist must exer- 

 cise his judgment with a view to applying his spray at an 

 opportune time both in regard to making it efifective and at the 

 same time to avoid all possible ill efi^ects that might be induced 

 by unfavorable weather. 



It is unlikely that a heat wave of such severity as that of 

 last summer will be known in Maine for many years, — perhaps 

 decades. Hence this question of sunscald in relation to spray 

 Injury will prove to be more a matter of scientific interest than 

 a practical obstacle to the fruit grower. It is probable that 

 with the highest of summer temperatures common to this State 

 experiments with the spray pump can be made which will throw 

 some light upon the relation of physical to chemical factors 

 in this problem. 



APPENDIX. 



A. — Expressing Ingredie;nts in Spray Formulas. 



In discussing spraying experiments it is customary for au- 

 thors to indicate the proportions of the materials used in a 

 definite order. In general, the formulas for bordeaux mixture 

 are given in the following order : Copper sulphate in pounds, 

 lime in pounds, and the volume to which the ingredients are to 

 be diluted with water, in gallons. Sometimes the amount of 

 lead arsenate is inserted between the figure representing lime 

 and that indicating final volume. 



For example : 3-3-50 bordeaux mixture means that 3 pounds 

 copper sulphate and 3 pounds of stone lime are used to make a 

 spray solution of 50 gallons. 3-3-2-50 means that 2 pounds of 

 lead arsenate have been added to the bordeaux of the strength 

 indicated, after said mixture has been made and is ready to be 

 applied. 



A similar rule applies to the formulas for making the home 

 boiled concentrated stock solution of lime-sulphur. In this 



