P-C-Benzene for the Peach-Tree Borer 7 



pulled away from the trunk (with a hoe) and fresh dirL free of para- 

 dichlorobenzene is replaced. In case short treatments are used in May or 

 early in June no dirt should be permitted to remain mounded about the tree 

 for the summer period. Remove the mound of soil and crystals about the 

 tree and permit the soil adjacent to the tree to be at general soil level. 

 Prolonged treatments on trees 3 to 5 years of age may produce unneces- 

 sary, and in some cases severe injury to the trunk and large roots. 



We do not recommend the use of para-dichlorobenzene on infested 1- 

 and 2-year-old peach trees in the orchard or for peach trees in the nursery. 

 In our experiments a large number of trees 1 and 2 years of age have been 

 given short treatments, % to }i ounce being used on 1-year-old trees, and 

 }i to y 2 ounce on 2-year-old orchard trees for 3 weeks, and satisfactory 

 results have been obtained. In some cases, however, considerable injury 

 has been produced, consequently we cannot give an unreserved recom- 

 mendation. Several reliable peach growers in New Jersey have made short 

 treatments (2 to 3 weeks) of % ounce on 1 -year-old trees and yi ounce 

 on 2-year-old trees for two seasons, and their orchards today appear to 

 be in fine shape. A goodly number of peach trees (several hundred) in one 

 nursery have been given short and long treatments with an average of % 

 ounce of para-dichlorobenzene per tree. The borers were killed, and 

 to date we have seen a surprisingly small amount of permanent injury. 

 Since our experiments have been conducted with nursery trees on only 

 one kind of soil, Penn loam, we cannot recommend the use of para- 

 dichlorobenzene for nursery stock. 



The author is of the opinion that the general condition or health of 

 an infested peach tree is as important as the age of the tree when one 

 considers susceptibility of the tree to para-dichlorobenzene. Trees weak- 

 ened by frost injury or other causes are more susceptible to injury from 

 para-dichlorobenzene than healthy trees. 



In our experiments several poorly kept (lacking cultivation, spraying 

 and fertilizers) and heavily infested orchards 6 to 12 years of age were 

 treated, and severe injury resulted. In some cases 10 per cent or more of 

 the trees died as a result of the treatment. The killed trees were- in poor 

 shape and the treatment undoubtedly hastened their death. Comparing 

 these results with those obtained in other heavily infested orchards that 

 received good care (ample and careful cultivation, spraying and fertilizers) 

 no trees were killed or seriously injured where para-dichlorobenzene treat- 

 ments were made. The author is convinced that weak trees and poorly 

 cared for trees are more susceptible to injury than healthy trees properly 

 cared for. In using para-dichlorobenzene one much remember that para- 

 dichlorobenzens is a fumigant toxic to plant and insect life. 



Dosage 



Doses of 24 to 1 ounce per peach tree 6 years of age or older kill 90 

 to 100 per cent of the peach-tree borers and produce little or no injury 

 in the average commercial orchard. One-half ounce per tree for 3 weeks 

 on trees 3 to 5 years of age gives satisfactory results provided the soil 

 temperature averages 55° to 70° F. In our experiments on 1- and 2-year-old 

 trees % ounce and Y% ounce per tree, respectively, have killed the borer. 



