Biological Control of Insect Pests: Southeast Asian Prospects - EcoPort

4.4 Aphis gossypii 73
Aphidius colemani Hym.: Aphidiidae (= A. platensis,
= A. transcaspicus)
Starù (1975) postulated that this species originated in India or nearby
(possibly the Eastern Mediterranean). It is now widely distributed in
Mediterranean Europe, Asia Minor, Central Asia, India, Pakistan, Africa,
South America, Australia, New Zealand and New Caledonia (Starù 1972). In
addition there have been intentional introductions to California, U.K.,
Czechoslovakia, Kenya (Starù1975) and Tonga (Carver et al. 1993). It is
rather strange, if it originated in India, that it appears to be absent from
Japan, China and possibly some of Southeast Asia (Starù 1975; Takada
1992). A. colemani is restricted to the family Aphididae. Hosts consist of at
least 9 species of Aphis, including A. craccivora and A. gossypii and at least
30 species in other genera (Elliott et al. 1994; Starù 1975).
In the field in Australia A. colemani is known to parasitise many species
in the aphid tribes Aphidini and Myzini, but rarely species in the
Macrosiphini and even more rarely species in other subfamilies (Carver et
al. 1993).
There are significant differences between countries both in the range of
hosts attacked by A. colemani and the preference for particular host species
(e.g. Messing and Rabasse 1995). This indicates that the species that is
known as A. colemani is a complex of closely-related species or biotypes.
For example, A. colemani parasitises Melanaphis donacis and Hyalopterus
pruni in Mediterranean Italy and France, but none of the many other aphids
present; in Central Asia only the latter aphid is attacked and in Iraq both
aphids are attacked, in addition to Aphis zizyphi and A. punicae. An Italian
population from Hyalopterus pruni was successfully reared on both Aphis
craccivora and A. fabae in the laboratory. Furthermore, a French population
from Melanaphis donacis was readily reared in the laboratory on Aphis
craccivora, A. fabae and Myzus persicae (Starù1975). As another example, a
strain (from Brazil) of Aphidius colemani successfully parasitised the
oleander aphid Aphis nerii in France whereas another strain (from France)
failed to do so (Tardieux and Rabasse 1986, 1988). In Mediterranean regions
A. colemani parasitised A. gossypii successfully at 20¡C, but at temperatures
above 27¡ it frequently failed to do so (Guenaoui 1991). The number of eggs
laid per female A. colemani was 302 at 20¡C and 388 at 25¡C and
development time to adult was 12.7 days and 10.0 days respectively. The
intrinsic rate of increase of the parasitoid was similar to that of A. gossypii,
suggesting that it is a promising parasitoid (van Steenis 1993). The optimum
scheme for introducing A. colemani into glasshouses for control of
A. gossypii on cucumbers has been investigated by van Steenis et al. (1996).
Chou (1984) recorded A. colemani from TaiwanÑthe first record of this
species from east AsiaÑwith H. pruni as its only host.