10 CIRCULAB 3 8 6, U. S. DEPARTMENT OP AGBICULTUBE 



directed, and is heavier than air. It is noninflaminable and nonex- 

 plosive. It kills adults and larvae of the wax moth but is not 

 effective against the eggs. 



In fumigating with paradichlorobenzene, the supers should be 

 stacked as tightly as possible and the cracks between supers covered 

 with gummed paper strips (fig. 5). A generous handful of the crys- 

 tals should be placed on the top of the frames of the top super and 

 the cover put tightly in place. The crystals may be sprinkled di- 

 rectly on the top bars of the frames, as in figure 5, or put on a piece 



Figure 5. — Supers loaded with comLi ready (or fumigatiou. Tlie joiiils are sealed with 

 gummed paper tape, and the crystals of paradichlorobenzene have been sprinkled 

 heavily over the top bars. 



of paper laid on the top bars. Since the gas is nonpoisonous and 

 not disagreeable, treatment may be made in ordinary storage without 

 taking the infected material out of doors. At intervals during the 

 storage season the covers of the stacks should be raised, and unless 

 some are still present, more crystals added. 



Paradichlorobenzene is at present as cheap as any of the materials 

 mentioned in this circular, with the exception of sulphur, and is by 

 far the easiest and least dangerous to use. The crystals last for some 

 time, since they volatilize slowly, and not only kill the larvae and 

 adults first present and the larvae as they hatch from the eggs, but 

 repel moths from outside which might otherwise enter and start a 

 fresh infestation. Paradichlorobenzene is most effective at tempera- 

 tures above 70° F. and volatilizes more rapidly as the temperature 

 rises. Inspections of stored materials should be made at intervals 

 of 2 or 3 weeks, depending on the temperature of the storehouse and 

 the prevalence of adult moths. 



