12 MANUAL OF FRUIT DISEASES 



of the concentrated solution (testing 32 Baume) to forty gak 

 Ions of water. To this is added arsenate of lead at the rate of 

 two pounds (paste ; or one pound, powdered) to each fifty gal- 

 lons of the diluted lime-sulfur. Aside from its insecticidal 

 value, the arsenate of lead increases the fungicidal value of the 

 lime-sulfur. Applications should be made as follows : (1) Just 

 before the blossoms open, but after the individuals of the clus- 

 ter have separated (Fig. 125, page 440). The period for effec- 

 tive spraying at this time is from one to three days. This 

 application should hold the set of fruit, if the fruit-pedicels are 

 thoroughly coated. This is the most important application 

 of all in a generally wet season. (2) Spray just after the 

 blossoms fall, beginning when they are two-thirds off (Fig. 126, 

 page 441). This application gives a clean crop of fruit. The 

 period for effective spraying is from two to five days. (3) Ten 

 days to two weeks after the second application, depending on 

 the weather conditions. In a dry spring this application may 

 be omitted. (4) The latter part of July or the first of August. 

 Again the grower is to be guided by weather conditions, al- 

 though ordinarily this application should not be omitted, as a 

 relatively clean crop may, be badly damaged by late infections, 

 if this application is not made. Sprayings in all cases should 

 be done before rain-periods, since the fungicide must be on the 

 susceptible part before the pathogene is. Effective fungicides 

 do not wash off sufficiently to destroy their efficiency. By 

 studying the low barometric areas indicated on the daily 

 weather map the orchardist should be able to predict weather 

 conditions for two or three days in advance. A nozzle .giving 

 a fine driving mist should be used. The material should be 

 applied at a pressure of 200 pounds. Spraying against the 

 wind instead of with it saves materials and labor and gives a 

 more effective distribution. Spray from a tower of sufficient 

 height to enable the operator to spray the highest parts. Spray 

 every season, never omitting the first, second, and rarely 



