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Saturday, June 6, 2015

The Worms Crawled in…I Scooped Them Out…

moth larvaeEvery time I get behind the wheel, driving solo, my wife exhorts me to “watch the road…you constantly gawk around while you drive, you know,”she exclaims. She’s right; I confess, especially this time of the year when I gaze off road at the blackberry bushes. They’ll bloom early this season thanks to the mild winter and early spring. Already I can see the flower spikes bursting with white blossoms like popcorn newly popped.

Blackberry is the Valley’s summer honey crop and noting the white frost spreading daily across the roadside blackberries (“gawking,” yes, but necessary gawking), I knew it was prudent for me to “go into” my bees and see what needed to be done for them so they could do what they needed to do for themselves to gather this season’s blackberry honey for me. Of particular concern was my little after swarm I hived in a five frame “nuc” box (“nuc” for “nucleus”) over a month ago. This little swarm had a virgin queen when I hived it, but subsequent inspections were favorable: she was mated and laying, the sign of a “queen-rite” colony. When I checked yesterday, three of the five frames had a nice, solid brood pattern, indicating the new queen was on the job, delivering the goods 110%. My plan for this little nuc was to marry it to another hive, specifically a four pound package I installed in mid-April. For some reason the new queen failed and I grafted two queen cells from a swarm-ready colony into the dwindling colony, which, thanks to my efforts, now has a laying queen. However, it will not build sufficient strength this season to bring in surplus honey, so I planned to combine it with the nuc colony….

Whoops. Gawking again, or as I’d scrawl in the margins of my students’ essays: “Off topic.” Back to the  inspection of the five frame nuc. As I pulled and examined the frames, I noticed some gauzy webbing under one of the end bars of the third frame. Then some movement, a creepy undulation I’ve seen before and recognized immediately: wax moth larvae. And sure enough, there was their signature, the gouged out runnels in the wood, the nasty presence of the Greater Wax moth (Galleria mellonella).moth weevil Why a viable, healthy hive tolerated these repulsive squirmy worms was a mystery to me. Bees are usually quick to dispatch intruders and cart them out of the hive. My guess was that one of the frames of drawn comb on which I hived them must have contained some moth eggs that hatched while the swarm was just getting started. Before the bees had built population strength, the wax moth larvae had cocooned themselves into a thick, cottony webbing, safely swaddled against the rightful proprietors of the hive.

Wax moths pose no threat to the bees themselves; usually they target dead out hive bodies, frames of old comb in boxes temporarily not in use or abandoned. The insects pose more an issue for the beekeeper who stores his combs for future use… in honey supers, for instance.  Two species of wax moth exist: G. mellonella (the Greater) and Achroia grisella (the Lesser). Both, according to my research, have world-wide distribution. I have battled grisella in my stored supers for as long as I can remember, but they’re easily controlled by scattering paradichlorobenzene (PDB) crystals on newspaper squares placed on top of the frames in the honey supers. Once the honey flow begins and the supers are installed, bees quickly clean out any residual webbing, cocoons, and larvae of the Lesser. A commercial beekeeper once told me he kept a “bug zapper” powered up in the shed where he stored his supers: the adult moths got fried…no adults, no burrowing offspring.cocoon corner

Mellonella can wreak havoc with drawn comb in idle boxes like catcher hives, boxes of drawn comb set out in the bee yard to attract passing swarms.These empty boxes are prime targets for adult moths who slither in at the entrance and lay their eggs. Once the eggs hatch, the ravenous larvae quickly build their protective webbing under which they tunnel at will through the combs, devouring meconium (cast off bee larvae and pupal skins), pollen pellets, and any residual honey.larvae frass and webbing The vigilant beekeeper should conduct periodic inspections of his catcher hives and empty hive bodies to check for mellonella’s presence. I learned my lesson after discovering a severe infestation in a two box deadout. Both boxes were webbed together so tightly it was impossible to remove the frames, difficult even to separate the two boxes. The rims of the boxes and tops of the frames were notched and runneled by the burrowing larvae, both boxes and contents totally ruined. Nothing left to do but burn the boxes, which I promptly did. webbed shutIf the moths are caught in time, the beekeeper can place the infested frames in the freezer for twenty-four hours, killing both eggs and larvae. A cautionary note: any comb stored out of doors is especially at risk for mellonella.

I scooped over a dozen of the plump, disgusting weevils from the nuc box and headed--not for the freezer but the chicken coop, tossed in the grubs and watched the four pullets make short work of them.

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1 comment:

  1. Good to see your chickens already helping you dispose of your pests.