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(Coleoptera, Diptera, Hymenoptera and Lepidoptera)
by
Brian Pitkin, Willem Ellis, Colin Plant and Rob Edmunds
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CUCURBITA.
Fig-leaved Gourd, Pumpkin and Marrow [Cucurbitaceae]
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Three
species of Cucurbita are recorded in Britain - Fig-leaved
Gourd (C. ficifolia), Marrow (Cucurbita pepo) and
Pumpkin (C. maxima). All are introduced.
Four British miners are recorded on Cucurbita.
A key to the European miners recorded on
Cucurbita is provided in Bladmineerders van Europa.
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Key for the identification of the known mines of British
insects (Diptera and non-Diptera) recorded on Curcurbita
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1a > Leaf-miner: A distinctive mine primarily above mid-rib, with irregular short
lateral offshoots into leaf blade. Pupation external (Spencer, 1972:
51 (fig. 172), 55; Spencer, 1976:
270, 271 (fig. 486)).
Branched,
whitish, upper-surface corridor; main axis overlying the midrib;
side branches overlying the main lateral veins. (In Campanula and Phyteuma the mine is much less branched, sometimes nothing
more than a corridor on top of the midrib). Frass in rather long
strings. Usually the mines begins as a long and narrow, shallow,
tortuous lower-surface corridor that ends upon the midrib but otherwise
is not associated with the leaf venation. Often this initial corridor
is filled with callus, and then even less conspicuous. Pupation
outside the mine.
A
linear mine on the upper surface, usually following the midrib and
showing side branches along the veins. The frass is in strings. |
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Polyphagous. On more than 40 host genera in 15 families, but not yet on Cucurbita, in Britain,. Widespread
throughout Britain. Also recorded in the Republic of Ireland.
Widespread in continental Europe.
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Liriomyza strigata (Meigen, 1830) [Diptera: Agromyzidae]. |
1b > Leaf-miner: Mine linear, whitish, both upper and lower surface. Pupation internal,
at the end of the mine with the anterior spiracles projecting through
the epidermis (Spencer, 1976:
433).
Upper-surface,
less often lower-surface corridor. Frass in isolated grains. Pupation
within the mine, usually in a lower-surface puparial chamber.
A long whitish upper surface corridor, which eventually goes lower surface. |
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Two
highly polyphagous species of Chromatomyia, with indistinguishable
mines, have been recorded in Britain. These are syngenesiae (Hardy) and horticola (Goureau) which can only be distinguished by the male genitalia. Both species are widespread in Britain and elsewhere, although syngenesiae is almost entirely restricted to Asteraceae. Records on Asteraceae not based on examination of male genitalia are treated in this account as Chromatomyia 'atricornis'.
Chromatomyia
horticola is recorded on 160 plant genera in 31 families of which 55 plant
genera in 19 families, including Cucurbita, in Britain.
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Chromatomyia
horticola (Goureau, 1851) [Diptera: Agromyzidae]. |
1c > Leaf-miner: A short, irregular, linear upper surface mine on any part of the
leaf. Also recorded from young pods (Bland, 1997a).
Long
corridor mine. As a rule the first part of the mine is lower-surface,
the later part upper-surface. Often the loops are so dense that
a secondary blotch is the result. Because upper- and lower-surface
corridor segments often cross, the mine obtains a strange array
of transparant patches. There is no association with the midrib.
Frass in strings and thread fragments. Pupation outside the mine;
exit slit in upper epidermis.
Mine not associated with the veins or midrib of the leaf (It is this character which enables distinction from another Agromyzid pest species - Liriomyza huidobriensis). The larvae may leave one leaf (if not large enough) and enter another leaf, via the petiole). It exits the leaf to pupate through a semi-circular slit in the upper surface of the leaf. |
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Polyphagous. On 119 plant genera in 31 plant families of which only 4 plant genera in 2 plant families, but not yet on Cucurbita, in Britain. Local, probably introduced
to Britain. Widespread in continental Europe particularly in Botanical
Gardens and glasshouses. Also recorded in Egypt.
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Liriomyza bryoniae (Kaltenbach, 1858) [Diptera: Agromyzidae]. |
1d > Leaf-miner: In the first instar the larva mines the leaves, forming short,
irregular, blotch-like mines, but in later instars it lives externally,
feeding in spun leaves and often twisting those of tender shoots. Larval head light-brown or yellowish brown, edged with black postero-laterally,
ocellar area blackish; prothoracic plate black edged with whitish
anteriorly; abdomen dull dark green; pinacula distinct, black,
sometimes brownish but with black bases to setae; anal plate large,
black (Bradley et al., 1973).
Small,
full depth mine without a definite shape; little frass. Some silk
is deposited in the mine. The larva soon leaves the mine and continues
feeding among spun leaves. |
Polyphagous. On numerous genera and species of plant families, but not yet
on Cucurbita, in Britain. On numerous genera
and species of plant families including Cucurbita elsewhere.
Widespread in Britain and continental Europe.
Also
recorded from the Channel Is.
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Cnephasia
incertana (Treitschke, 1835) [Lepidoptera: Tortricidae]. |
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