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Wax Moth

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Wax moth larvae (Galleria mellonella) are very destructive as they tunnel and chew their way through stored beeswax combs, ultimately resulting in their destruction if left untreated. Beekeepers require a control for wax moth to conserve their frames during periods of storage.

Healthy, populous honey bee colonies do not tolerate wax moth larvae in the hive. Wax moths are never the initial cause of colony destruction but in weak colonies their larvae can damage combs not covered and protected by bees.

Treatment:

At the end of season there are two methods to remove this pest :

1. Storing frames in a cold room or freezer.

2. Sending the frames (& honey supers) for irradiation.

WARNING: The use of para dichlorobenzene (PDB) or its derivatives is legally banned for use in the apiary industry. PDB is the substance found in moth balls & deodoriser blocks.

In the past, para-dichlorobenzene (PDB) has been used for the fumigant insecticide control of wax moth. PDB has not been registered for use as a wax moth control for some time.

It became apparent in late 2006 that PDB residues were persisting in a small proportion of honey production, stemming from historical use of PDB for wax moth control. Residues following comb fumigation are the result of PDB's tendency to accumulate in wax, which then leaches to honey following the filling of comb cells by the bees. In addition, testing of beeswax comb foundation has showed the on-going contamination of wax.

Life Cycle:

Adult moths are pale brown to grey, usually about 20 mm long. The grey wings are often mottled and appear as "roof" or "boat" shaped when folded over the body.Female moths usually lay 300 to 600 eggs in clusters on comb or in small cracks in hive material. The almost spherical, pinkish to white eggs are about 0.5 mm in diameter.

The eggs hatch within 3 - 5 days when temperatures range from 29oC to 35oC.

Larvae are creamy white, but turn grey on reaching their fully grown size of up to 28 mm in length. After hatching, the small very active larvae tunnel in comb, lining their tunnels with silky web as they go. They move from comb to comb through a mass of webbing.

Wax moth larvae are very active in warm weather, but become inactive in the extreme cold of winter. At the optimum temperature of about 32oC they reach full development about 19 days after hatching. At cooler temperatures, and when food is scarce, the larval period may extend to 5 months.

Fully developed larvae spin silky cocoons that may be found in a mass of webbing in the comb, and on the frames and internal surfaces of the hive. Larvae may form small canoe shaped depressions in the wooden hive components in which to spin their cocoons. Larvae can also bore through the wooden bars of frames.

Source : AHBIC March 2007.