New York Agricultural Experiment Station. 259 



dead at the time time of spraying. These trees were killed by 

 the undiluted petroleum (Table V.), The trees sprayed twice 

 (Table VII), with 60 per ct. and undiluted petroleum were 

 killed or seriously injured in every case. But those receiving 

 the weaker emulsions, 25 and 40 per ct., were uninjured in- 

 dicating that pear trees may be spraj^ed twice, once during the 

 winter and once during the early spring with a petroleum emul- 

 sion strong enough (40 per ct.) to kill the scale without being 

 injured. 



ORCHARD hi: APPLES. 



This orchard consists of thirty-two Baldwin apple trees in full 

 bearing. All were infested but none sufficiently to be seriously 

 weakened. They have been well cared for and, except for the 

 scale, are in good condition. 



The experiments were undertaken principally to ascertain 

 whether large trees moderately infested with the scale could be 

 satisfactorily treated with crude petroleum. The trees were 

 too large to make thorough spraying practicable without severe 

 pruning. They were therefore cut back severely in October and 

 finally sprayed, with the results shown in Tables VIII and IX. 



WmtJier during tests in Table VIII. — Winter treatment. Trees 

 sprayed Dec. 20 to 22. Average temperature of the three days 

 33°. 



Table VIII. — Winter Spraying in Orchard III. 



Trees. Strength 

 > of 



Degree of infestation. leum. Resnlts. 



Per ct, 



^-. ^ .. 



1 Extensively, 3 mod- 25 Scales not affected, 

 erately and 4 slight- Ti-ees uninjured, 



ly infested. 

 1 Extensively, 2 mod- 40 Scales dead, except 

 erately and 5 slight- on some of the 



ly infested. small branches 



where many live 

 ones were found. 

 5 trees dead, re- 

 mainder seriously 

 Injui'ed. 



