IT 



in a tower. The rule is, have a tower of such a height that the 

 hips of the man on the tower are well above the bulge of the 

 tree. 



Facilities for filling the tank should b'e such as to re- 

 quire a minimum of time. At the periods when spraying is 

 necessary time is too valuable to be used for anything else 

 than spraying. Filling tanks is not spraying. 



The fungicide and its application. I have already 

 pointed out the superiority of lime-sulfur for the control of 

 the apple scab. 



The strength or dilution required for a given fungicide 

 is determined as we have seen primarily by the minimum 

 strength required to kill the pathogen and the minimum 

 dilution necessary to prevent injury to the host plant. The 

 more these limits overlap the more satisfactory the fungicide 

 since the greater the margin of safety and efficiency. It is 

 now generally held that lime-sulfur diluted at the rate of 1 

 to 40 of a 32o Beaume concentrate, is most satisfactory for 

 the control of apple scab. Arsenate of lead is at present the 

 only known arsenical both safe and effective for use with 

 lime-sulfur. Dr. Wallace (N. Y. Cornell Bulletin 289 p. 140 

 and. 290 p. 178) has conclusively shown that the addition of 

 arsenate of lead actually increases the fungicidal value of 

 the mixture. 2 to 3 pounds of arsenate of lead per 50 gal- 

 lons of the dilute lime-sulfur is all that is required for ef- 

 fective control of the codling moth. 



Marker. Milk of lime has often been used and advo- 

 cated as an addition to the dilute solution for a marker. So 

 far as its effect on the fungicidal value of the lime-sulfur is 

 concerned Wallace's experiments seemed to show that it 

 actually increased it. (N. Y. Cornell Bui. 290 p. 185) We 

 have found the addition of three to five pounds of iron sul- 

 fate to a two hundred gallon tank of spray mixture the most 

 effective marker. It gives a black liquid which contrasts 

 sharply on the green foliage but soon turns to a rusty brown. 

 Its effect on the fungicidal value of solution has never been 

 satisfactorily determined. It does, however, markedly re- 



