12 N. J. Agricultural Experiment Stations Circular 156 



require l /i ounce of para-dichlorobenzene. Apply the crystals in the 

 manner described and then after the application is complete cover the 

 mound of soil with a paper cone so the soil and crystals will not be 

 disturbed when the trees are watered. If the roots are at the surface of 

 the soil when the para-dichlorobenzene is applied place an inch of soil over 

 them before the application is made. After 3 weeks completely remove 

 the gas-filled mound of .soil and crystals from the pots or tubs. Do not 

 permit crystals to remain on the surface, for subsequent watering will 

 wash the crystals into the soil and the roots may be seriously injured. 



The author has not had experience with greenhouse peach trees less 

 than 6 years old, consequently no recommendation will be made for trees 

 of this age. 



Plum and Cherry Trees 



So far as has been observed peach-tree borers in plum and cherry 

 trees 6 years of age or older can be safely and satisfactorily controlled 

 with para-dichlorobenzene. Follow the directions given for peach trees 6 

 years of age or older. 



Larvae of the American plum borer (Euzophera semifuneralis Walk) 

 commonly found in plum and cherry trees and occasionally in. peach trees 

 are killed by para-dichlorobenzene treatments provided the larvae are 

 located in the tree below ground or near soil level. The larva of this 

 insect is often located high on the trunk of the tree and in the large 

 branches. 



Borers in Other Plants 



Considerable, serious, or fatal injury is produced if para-dichloroben- 

 zene is used to kill the round-headed apple-tree borer (Saperda Candida 

 Fab.) in apple trees. In our experiments short treatment of J^ or 1 

 ounce for 3 weeks in the spring and fall produced some injury and did 

 not kill all of the borers. Prolonged treatments produced serious to fatal 

 injury. 



Considerable injury which may be fatal is produced if para-dichloro- 

 benzene is used to kill the blackberry crown borer (Bembecia marginata 

 Harris) in blackberry bushes. Both short treatments (3 weeks in length) 

 and prolonged treatments of y 2 . to 2 ounces per blackberry bush killed 

 most of the borers and injured and in most cases killed the bushes. 



Conclusions 



The peach-tree borer in trees of all ages may be controlled by the 

 "worming" process. 



Para-dichlorobenzene may be used in the control of the peach tree borer 

 in orchard peach trees 3 years of age or older. For trees in the nursery 

 or 1- and 2-year-old trees in the orchard there still exists an element of 

 doubt as to the advisability of an unreserved use of para-dichlorobenzene. 

 Peach-tree borers in greenhouse peach trees 6 years of age or older may 

 be controlled with para-dichlorobenzene. 



Para-dichlorobenzene may be used in the control of peach-tree borers 

 in plum and cherry trees 6 years of age or older. 



Para-dichlorobenzene is very toxic to apple trees and blackberry bushes, 

 consequently borers in these plants cannot be safely controlled with this 

 fumisrant. 



