Therefore, Trioxys pallidus has been considered as the most important biological
control of the walnut aphid, Chromaphis juglandicola, but it can be found rarely on
other species. The same pattern is recorded from many other Trioxys species (Starý
1978), while Trioxys complanatus can be an exceptional case, which showed a great
preference both on its specific host aphids, Therioaphis trifolii and the host plants,
alfalfa and clover (Rakhshani et al. 2006a – alfalfa aphids). It is a good representative
of successful classical biological control program, when introduced into USA at
1956 and it is now distributed in the North America (van den Bosch 1957; Flint
1980) and in Australia (Hughes et al. 1987).
The number of the narrow oligophagous species therefore covers the majority of
Aphidiinae species both in Iran and other parts of the world. The representative
species with their confirmed specific host range is presented in Table 9.1.
9.2.3.2 Broadly Oligophagous Aphid Parasitoids
Assigning the term “polyphagous” to the aphid parasitoids is essentially incorrect.
Almost all parasitoids indicated some patterns of host specificity. Aphidiines are
exclusively parasitoids of the aphids, which means a natural definition opposite to
polyphagy. There is no absolute criterion to separate “narrow” and “broadly”
oligophagous groups, based on the dynamic and poorly known biology and evolutionary history of the aphids and their parasitoids. The main aspect of this categorization is the rate of diversification in the aphid lineages. This statements might be
more simplified by some examples, but clearly referring to association of a known
parasitoid with aphid species of single highly diverse genus or several related genera.
On the other hand, there are some parasitoids species, like Praon volucre (Haliday)
acquired a more expanded host range. It was found in association with aphids of the
genera, Acyrthosiphon Mordvilko (2 species), Amphorophora Buckton (1), Aphis
L. (8), Brachycaudus van der Goot (4), Diuraphis Aizenberg (1), Dysaphis Börner
(1), Hyalopterus Koch (2), Hyperomyzus Börner (1), Macrosiphum Passerini (1),
Macrosiphoniella del Guercio (1), Metopolophium Mordvilko (1), Myzus Passerini
(2), Phorodon Passerini (1), Rhopalosiphum Koch (2), Schizaphis Börner (1),
Sitobion Mordvilko (1) and Uroleucon Mordvilko (4) in Iran. Lysiphlebus fabarum
(Marshall) has been known as a parasitoid with a vast number of recorded host
aphids, at least 65 species in Iran (Farahani et al. 2016). But surprisingly, its real host
range is limited to few closely related aphid genera, Aphis, Brachycaudus and Myzus
(Rakhshani et al. 2013). Other host records contributed to occasional associations or
possibly separated but cryptic species inside the Lysiphlebus fabarum complex.
There are many important aphid parasitoids including Aphidius ervi Haliday,
Aphidius platensis Brethes, Aphidius matricariae Haliday, Diaeretiella rapae
(M’Intosh) and Ephedrus persicae Froggatt, of which some of them are now the
biological control products, commercially sold.
An important aspect on the biology of these species is that their host range covers
many aphid pests on the field crops, fruit trees and greenhouses. Near to hundred
aphid species infesting 180 plant species (43 families) are listed as hosts of
342
E. Rakhshani and P. Starý
control of the walnut aphid, Chromaphis juglandicola, but it can be found rarely on
other species. The same pattern is recorded from many other Trioxys species (Starý
1978), while Trioxys complanatus can be an exceptional case, which showed a great
preference both on its specific host aphids, Therioaphis trifolii and the host plants,
alfalfa and clover (Rakhshani et al. 2006a – alfalfa aphids). It is a good representative
of successful classical biological control program, when introduced into USA at
1956 and it is now distributed in the North America (van den Bosch 1957; Flint
1980) and in Australia (Hughes et al. 1987).
The number of the narrow oligophagous species therefore covers the majority of
Aphidiinae species both in Iran and other parts of the world. The representative
species with their confirmed specific host range is presented in Table 9.1.
9.2.3.2 Broadly Oligophagous Aphid Parasitoids
Assigning the term “polyphagous” to the aphid parasitoids is essentially incorrect.
Almost all parasitoids indicated some patterns of host specificity. Aphidiines are
exclusively parasitoids of the aphids, which means a natural definition opposite to
polyphagy. There is no absolute criterion to separate “narrow” and “broadly”
oligophagous groups, based on the dynamic and poorly known biology and evolutionary history of the aphids and their parasitoids. The main aspect of this categorization is the rate of diversification in the aphid lineages. This statements might be
more simplified by some examples, but clearly referring to association of a known
parasitoid with aphid species of single highly diverse genus or several related genera.
On the other hand, there are some parasitoids species, like Praon volucre (Haliday)
acquired a more expanded host range. It was found in association with aphids of the
genera, Acyrthosiphon Mordvilko (2 species), Amphorophora Buckton (1), Aphis
L. (8), Brachycaudus van der Goot (4), Diuraphis Aizenberg (1), Dysaphis Börner
(1), Hyalopterus Koch (2), Hyperomyzus Börner (1), Macrosiphum Passerini (1),
Macrosiphoniella del Guercio (1), Metopolophium Mordvilko (1), Myzus Passerini
(2), Phorodon Passerini (1), Rhopalosiphum Koch (2), Schizaphis Börner (1),
Sitobion Mordvilko (1) and Uroleucon Mordvilko (4) in Iran. Lysiphlebus fabarum
(Marshall) has been known as a parasitoid with a vast number of recorded host
aphids, at least 65 species in Iran (Farahani et al. 2016). But surprisingly, its real host
range is limited to few closely related aphid genera, Aphis, Brachycaudus and Myzus
(Rakhshani et al. 2013). Other host records contributed to occasional associations or
possibly separated but cryptic species inside the Lysiphlebus fabarum complex.
There are many important aphid parasitoids including Aphidius ervi Haliday,
Aphidius platensis Brethes, Aphidius matricariae Haliday, Diaeretiella rapae
(M’Intosh) and Ephedrus persicae Froggatt, of which some of them are now the
biological control products, commercially sold.
An important aspect on the biology of these species is that their host range covers
many aphid pests on the field crops, fruit trees and greenhouses. Near to hundred
aphid species infesting 180 plant species (43 families) are listed as hosts of
342
E. Rakhshani and P. Starý