434 STATE BOARD OF AGRICULTURE. 



make any particular application at exactly the period we consider ideal; 

 some have to be sprayed before and some after the ideal period. This would, 

 of course, hold true with the ''pre-pink" application and in seasons when 

 the temperature is high at this period, it may be necessary to begin the pink 

 application as soon as the "pre-pink" one is finished. 



Material to use. Any of the common fungicides used for summer applica- 

 tions may be used for the "pre-pink" application. Bordeaux mixture should 

 give satisfactory results at the usual strength. A stronger solution of lime- 

 sulphur than is used during the summer may be applied with safety at this 

 time. Some growers use it at this time at the rate of 23^2 gallons in 50 and 

 even the full dormant strength has been used without any injury other than 

 to burn some of the first leaves which appear with the blossom buds. The 

 dormant strength, however, is not recommended for use so late as the "pre- 

 pink" stage as there may be weather conditions under which it would cause 

 severe injury to the fruit buds. 



00M1»ARATIVE DUSTING AND Sl'KAYING OF AP1»LES 



AND PEARS. 



EXPERIMENTS WITH APPLES. 



Summary of previous work. Dusting experiments with apples were begun 

 in 1915 and have been continued in some form each year. The results of 

 these earlier experiments have been published but will be reviewed briefly 

 at this time. In 1915 and 1916 the control of apple scab by dusting or 

 spraying was not satisfactory in these experiments so that no reliable com- 

 parison of the dusting and spraying methods could be made. Both of these 

 years were very favorable for the development of scab because of frequent 

 and heavy rains. 



In 1917, 1918 and 1919 dusting and spraying gave equally satisfactory 

 results in the control of apple scab. Weather conditions, except in 1917, were 

 not severe and this may have had some effect on the results. Codling moth 

 injury was not in evidence in many of the experiments but where there was 

 any infestation the control by dusts was satisfactory. 



In several experiments the foliage of trees in dusted plots was in better 

 physical condition than that of sprayed trees. This difference was quite 

 marked in some instances and in others there was little difference. 



Object of the experiments. The experiments conducted in 1920 and 1921 

 were for the purpose of getting additional information as to the comparative 

 value of the dusting and spraying methods of apphcation, in the control of 

 apple scab and codling moth, particularly under conditions which had not 

 been encountered in earlier work. The effect of dusting materials upon the 

 physical condition of the foliage was also to be studied and certain new 

 forms of dusting materials were to be compared with the standard sulphur 

 dust. 



