Introduction to Fungi, Third Edition

ENTOMOPHTHORALES
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Fig 7.41 Erynianeoaphidis.(a)Hyphalbodyfrom
within an infected aphid. (b) Pointed
pseudocystidium projecting above a layer of
conidiophores at the surface of a dead aphid.
(c) Direct germination of a secondary conidium.
Cytoplasm is confined by a retraction septum to
the tip of the germ tube. (d) Branched
conidiophore with terminal primary conidia.
The wall surrounding the conidium is bitunicate
with a thin outer envelope. (e) Discharged
uninucleate primary conidium. (f) Discharged
secondary conidium.Compare its more ovoid
shape with the shape of the primary conidium.
(g) A discharged secondary conidium has
germinated by repetition to form a further
conidium of the same type. Note the bulging
septum on the empty conidium and at the
base of the newly developed conidium.
(h) Primary conidium germinating to form
a secondary conidium. Both are bitunicate.
(i) Secondary conidium germinating to form
a tertiary conidium with a single large lipid body.
(j) Tertiary conidium germinating by
repetition. (a,b) ¼ 20 mm; (c j) ¼ 12.5 mm.
used as inoculum to introduce the parasite
into field populations of aphids pathogenic to
crops, such as Aphis fabae, the common blackfly
of broad beans. It is also possible to grow
E. neoaphidis in agar culture and to introduce
inoculum into aphid-infested crops in this form
(Shah et al., 2000).
Erynia conica
Whilst E. neoaphidis shows some versatility in its
asexual reproduction, a more extreme example
is E. conica, which forms four distinct types
of conidium, some of them primary and some
secondary (Descals et al., 1981; Hywel-Jones &
Webster, 1986a). Erynia conica is a parasite of the
blackfly Simulium (Diptera) and some other insect
hosts associated with aquatic habitats. Simulium
spp. have aquatic larval stages generally found in
rapidly flowing streams. The larvae are attached
to stones, twigs and aquatic plants, feeding by
the ingestion of particulate matter collected
by modified branched mouthparts (head rakes).
After pupation, winged adults emerge, mate, and
the females take a blood meal from a mammal.
Gravid females lay egg masses amongst algae and
mosses on water-splashed boulders kept continuously
wet by trickling water. At such sites the
white swollen bodies of dead females infected
by E. conica, attached by rhizoids, may sometimes
be found in large numbers. Conidiophores
project from the carcass, bearing conidia of two
types. From conidiophores which develop in air,
i.e. at the surface of the insect’s body projecting
out of water, boat-shaped bitunicate conidia