We have two types of wax moth in North Canterbury,
Achroia grisella has a length of 10-13mm, a wingspan of 11-14mm and is silvery-grey to buff in colour with a yellow head.
When seen it either flys, runs very quickly or holds onto the comb vibrating its wings.
Each female can lay 250-300 eggs hatching into larvae that are similar in appearance to Greater Wax Moth larvae but not as large being up to 20mm in length.
Though larvae consume honey, pollen and wax they are not found in comb occupied by bees and do not damage hive components.
Lesser Wax Moth larvae are unable to compete with Greater Wax Moth larvae as the latter will eat them.
If not controlled wax moth infestations can rapidly multiply, which is exacerbated with warmer conditions.
Wax moths like warm, dark and still conditions, so if we do the opposite we have a cold light and airy situation that will deter them. In the live bee situation the best preventative against wax moths is strong healthy colonies.
Lesser Wax Moth Photo © Shane Farrell
Galleria mellonella has a length of about 20mm, a wingspan between 24 and 33mm and is a brown colour with ash white markings.
When seen in a hive it makes short runs or flights to darkness. It can sometimes be seen perching and flying in the vicinity of bee colonies at dusk usually entering hives or boxes at that time.
Females lay clumps of eggs in crevices within the hive, laying between 300 and 600 eggs which are pink/cream/white and are difficult to see. They hatch after 5–8 days into the larvae that cause the damage to bee combs.
The larvae grow to 24-33mm length and when they larvae pupate often burrow into wooden frame components leaving tell tale holes often next to frame lugs, or adjacent to the hive walls leaving tell tale boat shaped furrows about 15mm long.
These larvae cannot ingest beeswax but eat it and live on the impurities contained therein. As a result they are generally found in the brood comb or any comb containing organic matter.
The larvae burrow through combs often just under the cappings leaving a silken tunnel behind them. The bee pupae in the cells are rarely damaged, but sometimes become trapped in the cells by the silk threads and die. This condition is known as Galleriasis and is more frequent in newly drawn comb.
In serious infestations the entire box can be filled with pupae in white silk cocoons. These are usually accompanied with dark specks of frass. On emergence adults mature and usually mate within the hive.
Photo © Josef Dvořák
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Images © of the respective photographers