P-C-Benzene for the Peach-Tree Borer 9 



are favorable for the most satisfactory results in soil fumigation for the 

 control of the peach tree borer. A clean-up of the peach-tree borer in the 

 fall means uninfested trees from October to July or August the following 

 year when the new brood appears. One application per season is sufficient 

 if the application is carefully and properly made in the fall. 



Para-dichlorobenzene will kill the borers present in a peach tree but it 

 will not prevent an infestation. Newly hatched larvae will enter and live in 

 peach trees that have a "death-ring" of para-dichlorobenzene about them. 

 The point of entrance of the larvae is near the top of the mound of soil 

 placed over the para-dichlorobenzene. Furthermore, adult females will de- 

 posit eggs on peach trees that have para-dichlorobenezene about them. 

 Several growers in New Jersey have experienced poor results with para- 

 dichlorobenzene in the control of the peach-tree borer because they applied 

 the fumigant late in August or early in September before all of the eggs 

 had hatched. 



In case a fall application is not made or poor results were obtained a 

 short spring treatment during the month of May will give fairly satisfac- 

 tory results. During May the soil is sufficiently warm to produce good 

 results in 3 weeks' exposure. The percentage of dead borers may be a 

 little smaller than from a similar treatment made in the fall. If a spring 

 application is made most of the larvae present in the tree will be killed but 

 this will not keep the borers out during the summer months. In other 

 words, an application should be made again in the fall. So far we have 

 seen no serious results where trees 3 years of age or older received two 

 applications per season. 



Mid-summer applications are useless, for the peach-tree borer may be 

 found in all stages — egg, larva, pupa and adults — and the treatment will 

 only kill the larvae and pupae. Furthermore, the high soil temperature of 

 mid-summer produces a rapid evolution of the gas and this in turn pro- 

 duces the maximum amount of injury. 



Late fall applications, made after October 15 and before the ground 

 freezes on trees 3 years of age or older, will kill most of the borers in 

 the trees provided the para-dichlorobenzene is allowed to remain in the 

 ground until the soil temperature becomes approximately 60° the following 

 spring. Some injury may be produced by a late application. 



In several 3-year-old orchards, where para-dichlorobenzene remained 

 about the trees from October 15 or later to April 1, May 1 and June 1, the 

 greatest amount of injury occurred on the trees uncovered June 1. If a 

 late application is made on trees 3 to 5 years of age it is advisable to remove 

 the crystals of para-dichlorobenzene the following spring late in April or 

 early in May before the soil temperature becomes too high. 



Greenhouse Peach Trees 



Infested peach trees grown in pots, tubs or in the ground in green- 

 houses may be treated with para-dichlorobenzene to control the borer. The 

 safest and most satisfactory time of the year is in the fall immediately 

 after all of the eggs have hatched and when the trees are more or less 

 dormant or losing their leaves. Dwarf peach trees 6 years of age or older 



