Chalkbrood - Status Today and Hopes for Control' - Golden Rule Honey

i:'
':,
82 PESTS, PREDATORS, AND DISEASES
and Taber (7973) reported chalkbrood in Ariz'na, and Co.nor
(1974a) found chalkbroocl in ohio. By 1974, the disease had been
found in at least 35 states (De jong 1976).
.Gochnauer, Hugh6s, and Conner (1972) reported the first record
of chalkbrood in Ca.ada in honey bees from British Columbia
and Saskatchewan. Nelson, Barker, Blancl, Corner, Soehngen, and
vilieneuve (1976) surveyed 5,374 coronies in five prorlinces of
Canada and found that 32 per cent of these colonies hid mummies
in the frames. Ilorvever, is per cent of the infected colonies had
less than ten cells rvith charkbrood. Ii is possible that the disease
rvas Llnreported for some years in Canacla ancl the u'ited states
(Gochna'er, Furgala, ancr shimanuki1975), since cornmercial beekeepers
indicated that trre discase had been prese.t for decacies
but rvas considered insignificant in comparison to American foul_
brood (Connor 1974b).
Etiology'
According to Bailey honey bee larvae
!!9-67),
are most susceptibie
to chalkbrood disease if they i.gesi spores of Ascosprtnern aTtis i"h"r-,
they are threc to four clal'5 ord anci then are crriileci briefly trvo
clays latcr imrnediatell, after they are sealeci in their cells to pirpatc.
Because of the chilling factor, the affectecr rarvae are usualri iJr'a
on.the peripherl. of the broocl area. For this reasorr, it rr.as once
believed that only drone ra^'ac *'ere affectecr since tire' are frequerrtly
on the periphery of the brood nest.
spores
. the^ th" germin ate in t,iro in trre gui of the larvae n hich
is alm'st anaerobic. Horvever, the mycelitim is aerobic and, there,
fore, survi'es in three to four-day,-olcr larvae better thai, in
younger brood because of the shortei time it is deFrrived of oxygen
(lt"y 1967). The spores germi'ate p;rrticurarry ln the hi.d encl
of the gut. When the larva becomes sealecl in its ce.ll to
the mycelium
f,rpate,
breaks out of the hincl end of the bor1r. (Bailey t'0621.
since Ascosphaera apis is a heterothalric orga'ism, the iarva is
transformed into a rvhite chalklike munlnlr,, rvilen the rtrvcelium of
only o.e strain (+ or --) infects a rarva. hihen the myceiia of both
strains grorv in a larva, fruiting bocries are for'retl ,r., th" outsicre
of the dead larva, and tl-re r,r**1, becomes gr.a1, 1o black (Figure
5.2).
At first the clead larvae are covered u,ith a flulfi, rvhite gro.rvth of
myceli.r and are srvollen to thc size of the ccll. Latcr, the clead
larvae dry irrto harcl, shrunken, chalklike lrrinps, rvhich nav be-
Figu
Snri
con
of t.
mul
of li
in tl
mie
boa'
Bi
infe,
u'itl
ancl
took
ck-s;
tire.:
post
mair
tion-.