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Metaphycus helvolus
Encyrtid wasp, a parasitoid of
soft scales
Photography by Max E. Badgley
(1922-2006)
| Metaphycus helvolus female, on black scale. |
| Photo ©
Max E. Badgley, published with
permission from the Max E. Badgley Estate, with special thanks to
the University of California, Riverside, who kindly supplied this
image from the UCR Chalcidoidea database collection. |
This small encyrtid wasp, native of South Africa, was introduced in
California in 1937 to combat black scale, a serious pest of citrus. Once
M. helvolus became established in southern California, black scale
reverted to the status of a secondary pest of citrus. M. helvolus
thrives in semi-tropical areas and in greenhouses, but cannot survive cold
winters. It is polyphagous, with a wide range of hosts, including black
scale, hemispherical scale, brown soft scale, nigra scale, citricola
scale, and European fruit lecanium.
Female M. helvolus are orange-yellow in color; males are dark
brown. Mature females lay several eggs a day in the softer bodies of 2nd
and 3rd-instar scales whose coverings are easily penetrated by their
ovipositors. Besides parasitizing scales in this manner, the wasp also
feeds on the body fluids of other, less mature scales, and on nectar and
honeydew from a variety of sources.
M. helvolus is reared by insectories for use in greenhouses.
Text compiled and edited
by J.Cates, curator
Badgley Photography
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