6 CIRCULAR 3 8 6, U. S. DEPARTMENT OF AGRICULTURE 



CONTROL 



Control Measures in the Apiary 



Beekeeping practices and manipulations should be based on the 

 assumption that the wax moth in some stage may be present in the 

 hives at all times. The bees are the most effective natural enemies 

 of wax moths. The bees will, when the colony is strong, carry 

 the moths out of the hive, and there is no better insurance against 

 the ravages of the pest than to have strong queenright colonies. Ac- 

 cidental loss of queens in colonies late in the fall may mean the loss of 

 colonies from wax moth damage before the first spring examination. 



In addition to strong colonies the best control measure is cleanli- 

 ness of hives — removal of propolis, bur combs, and refuse on the 

 bottom board, which provide protection for larvae of the wax moth, 

 even in strong colonies. 



From the standpoint of both productive beekeeping and wax 

 moth control, box hives or hives in which the frames are not easily 

 movable should be replaced by modern equipment. Such hives give 

 the wax moth an opportunity to reproduce, and they provide breed- 

 ing places from which other colonies may be attacked. 



Control of the wax moth by trapping the adults at lights or by 

 means of trap combs has not been successful. 



Control Measures for Stored Combs 



Since light and air repel both the adult moths and the larvae, 

 stored combs will be less subject to destruction if they are exposed 

 to the light by setting the supers on end and spaced to allow ven- 

 tilation. The common method of storing combs in tightly closed, 

 crowded hive bodies is highly favorable to wax moth infestation 

 and development. 



The use of chemicals to kill the wax moth has proved the most 

 satisfactory measure thus far for controlling this insect in stored 

 combs. Several fumigants have found favor for this purpose, par- 

 ticularly paradichlorobenzene, carbon disulfide, and calcium cyanide. 

 Other fumigants that have been used include fumes from burning 

 sulfur, carbon tetrachloride, and methyl bromide. These materials 

 have been found to kill all stages but the egg^ and methyl bromide is 

 even effective against the eggs of the wax moth. Some of these fumi- 

 gants, however, have definite limitations ; on others not enough research 

 work has been done with the wax moth to justify recommendation of 

 their use to beekeepers. 



paradichlorobenzene 



Paradichlorobenezene ("PDB") is a white crystalline substance 

 which evaporates slowly in air. The gas is not unpleasant to smell 

 and when used as directed will not be found injurious to people. Higher 

 concentrations, however, are irritating, and the crystals must be 

 handled in such a manner as to prevent their being taken internally 

 by accident. It is heavier than air, noninflammable, and nonex- 

 plosive. 



In paradichlorobenezene fumigation the supers should be stacked 

 as tightly as possible and the cracks between them covered with 



