8 N. J. Agricultural Experiment Stations Circular 156 



Method of Application 



Prepare a tree for an application of para-dichlorobenzene by removing 

 with a hoe the weeds, grass, leaves, stones, sticks, etc., from about the 

 base of the trunk for a distance of 6 to 12 inches. In other words, clear 

 away the trash and make the soil smooth about the base of the tree. Do 

 not dig into the surface any more than necessary. In case large masses of 

 gum are present remove most of it with a hoe or some similar tool. 



When the tree is ready for treatment measure out the amount of para- 

 dichlorobenzene to be used in some container which is graduated or holds 

 when level full the required amount; a short wide-mouth bottle, a tin or 

 wooden pill-box may answer the purpose. Some growers measure out 

 1 ounce in a closed fist. Take a handful of the crystals and then close 

 your hand tightly with the first joints of the fingers straight. The size 

 of your hand will determine the amount you can hold in this way 



The crystals should be evenly distributed in a continuous narrow cir- 

 cular band approximately 2 inches from the tree. Do not place the crystals 

 against the trunk, for serious injury may result. Material placed 4 to 6 

 inches from the tree has given fairly satisfactory results provided the soil is 

 dry and plenty of dirt is placed above the crystals. 



After the material is in a ring about the tree, place several shovelfuls 

 (four to six) of dirt free of weeds, grass, sticks, large stones, etc., over 

 the crystals and compact them with a shovel or a hoe or otherwise. The 

 first shovelful of earth placed above the "death ring" should be finely 

 divided and carefully placed upon the crystals in order that the position 

 of the para-dichlorobenzene will not be disturbed. 



If infestations are located high in the tree, 1 to 6 inches above the soil, 

 the larvae so located can be killed by piling a large amount of dirt over the 

 crystals (at soil level) and above the highest infestation. Or the applica- 

 tion may be divided, placing half of the required amount at soil level, and 

 covering this with several (2 to 5) inches of soil, and then placing the re- 

 maining half of the dose on the upper level and covering this again with 

 several inches of soil. The last method is more apt to give satisfactory 

 results than the first. If crystals are placed on a newly constructed mound 

 of soil several inches above soil level and no crystals are placed at soil level 

 the larvae above ground will be killed but the gas will not penetrate the 

 ground in sufficient quantity to kill the larvae located in the trunk or large 

 roots several inches below the surface. 



Time of Application 



The results of several seasons of experiments and observations with 

 para-dichlorobenzene show that the best time to apply the f umigant is in the 

 fall immediately after all of the eggs of the peach-tree borer have hatched. 

 For an average season in New Jersey this is September 15 for the northern 

 half of the state and October 1 for the southern half. A fall treatment is 

 most satisfactory because the majority of the larvae are small and easy to 

 kill. In the fall most of the larvae are located in the outer layers of the 

 trunk and roots, the trees exudes less gum than in the spring and the soil 

 is apt to be dry, or at least not saturated with water. All of these facts 



