6.2 Family Trichogrammatidae Foerster, 1856
The family Trichogrammatidae involves the smallest members of the order Hymenoptera, superfamily Chalicidoidea. Adults are mate without metallic shine, often
less than 1 mm in length (mostly 0.18–1.5 mm), without narrow stem between
mesosoma and metasoma, and are distinguished by their 3-segmented tarsi from the
other Chalcidoidea (Pinto and Stouthamer 1994). The native species of
Trichogramma in Iranian plateau are commonly small (0.2–0.4 mm), with yellow,
brown or black body. Trichogramma spp. have been spread in humid southern
coasts of the Caspian Sea (Guilan, Mazandaran and Golestan provinces), the southern foothills of the Alborz Mountains, the Zagros mountains, central provinces and
even borderlines of the central desert of Iran (Shojai 1987).
This family consists of about 800 species in ca. 83 genera which are dispersed
worldwide. Most genera of the Trichogrammatidae have few species (55 genera
have only five species or less) and only 14 genera have more than 10 species. Almost
all species of Trichogrammatidae are primary, solitary or gregary endoparasitoids of
other insects’ eggs belonging to various orders. There is only one report of parasitism on a stage other than egg; that is related to Cecidomyiidae (Diptera) pupa
(Viggiani 1981). The trichogrammatids have a broad host range. At least 400 species
in 11 orders of insects are targets for trichogrammatids, including Homoptera
(29 genera), Coleoptera (11 genera), Lepidoptera (8 genera), Hemiptera (6 genera),
Orthoptera (4 genera), Diptera (3 genera), Odonata (2 genera), Hymenoptera
(1 genus), Thysanoptera (1 genus) and Neuroptera (1 genus) (Hassan et al. 1988;
Ciochia 1991; Nikonov et al. 1991; Pintureau 1991a; Pinto and Stouthamer 1994;
Romeis and Shanower 1996; Ebrahimi 2004). Among these hosts, both agricultural
pests and beneficial insects are observed (Pintureau 1991b). The most common hosts
in Iran are moth eggs particularly belonging to Noctuidae, Pyralidae, Tortricidae,
Pieridae, Crambidae etc. (Shojai 1987).
The species of Trichogrammatidae are used in miscellaneous agroecosystems
throughout the world. They have been used against 28 insect pests in more than
30 million hectares of products such as corn, rice, sugarcane, cotton, vegetables,
sugar beet, fruit trees and softwoods at 30 countries (Li 1994; van Lenteren and
Bueno 2003). More recent estimates show that currently 15 million hectares are
treated with Trichogramma spp. in globe (Bueno and van Lenteren 2010). The
features that make these wasps good biocontrol agents are numerous generations,
polyphagy, adaptation to various weather conditions and easy way of rearing on
factitious hosts. Russia, China, Mexico, Europe, the United States and some central
Asian countries, are the major consumers of trichogrammatids in the world (Li 1994;
Bueno and van Lenteren 2010).
Trichogramma Westwood is the largest and a well-known genus of
Trichogrammatidae with more than 200 species around the world (Pinto 2006).
Trichogramma and Oligostia (with 110 species), include 40% members of this
family. Trichogramma spp. are the most widely studied and successfully used
natural enemies regarding their short generation time, easy mass rearing in
6 Egg Parasitoids: Chalcidoidea with Particular Emphasis on Trichogrammatidae
199
The family Trichogrammatidae involves the smallest members of the order Hymenoptera, superfamily Chalicidoidea. Adults are mate without metallic shine, often
less than 1 mm in length (mostly 0.18–1.5 mm), without narrow stem between
mesosoma and metasoma, and are distinguished by their 3-segmented tarsi from the
other Chalcidoidea (Pinto and Stouthamer 1994). The native species of
Trichogramma in Iranian plateau are commonly small (0.2–0.4 mm), with yellow,
brown or black body. Trichogramma spp. have been spread in humid southern
coasts of the Caspian Sea (Guilan, Mazandaran and Golestan provinces), the southern foothills of the Alborz Mountains, the Zagros mountains, central provinces and
even borderlines of the central desert of Iran (Shojai 1987).
This family consists of about 800 species in ca. 83 genera which are dispersed
worldwide. Most genera of the Trichogrammatidae have few species (55 genera
have only five species or less) and only 14 genera have more than 10 species. Almost
all species of Trichogrammatidae are primary, solitary or gregary endoparasitoids of
other insects’ eggs belonging to various orders. There is only one report of parasitism on a stage other than egg; that is related to Cecidomyiidae (Diptera) pupa
(Viggiani 1981). The trichogrammatids have a broad host range. At least 400 species
in 11 orders of insects are targets for trichogrammatids, including Homoptera
(29 genera), Coleoptera (11 genera), Lepidoptera (8 genera), Hemiptera (6 genera),
Orthoptera (4 genera), Diptera (3 genera), Odonata (2 genera), Hymenoptera
(1 genus), Thysanoptera (1 genus) and Neuroptera (1 genus) (Hassan et al. 1988;
Ciochia 1991; Nikonov et al. 1991; Pintureau 1991a; Pinto and Stouthamer 1994;
Romeis and Shanower 1996; Ebrahimi 2004). Among these hosts, both agricultural
pests and beneficial insects are observed (Pintureau 1991b). The most common hosts
in Iran are moth eggs particularly belonging to Noctuidae, Pyralidae, Tortricidae,
Pieridae, Crambidae etc. (Shojai 1987).
The species of Trichogrammatidae are used in miscellaneous agroecosystems
throughout the world. They have been used against 28 insect pests in more than
30 million hectares of products such as corn, rice, sugarcane, cotton, vegetables,
sugar beet, fruit trees and softwoods at 30 countries (Li 1994; van Lenteren and
Bueno 2003). More recent estimates show that currently 15 million hectares are
treated with Trichogramma spp. in globe (Bueno and van Lenteren 2010). The
features that make these wasps good biocontrol agents are numerous generations,
polyphagy, adaptation to various weather conditions and easy way of rearing on
factitious hosts. Russia, China, Mexico, Europe, the United States and some central
Asian countries, are the major consumers of trichogrammatids in the world (Li 1994;
Bueno and van Lenteren 2010).
Trichogramma Westwood is the largest and a well-known genus of
Trichogrammatidae with more than 200 species around the world (Pinto 2006).
Trichogramma and Oligostia (with 110 species), include 40% members of this
family. Trichogramma spp. are the most widely studied and successfully used
natural enemies regarding their short generation time, easy mass rearing in
6 Egg Parasitoids: Chalcidoidea with Particular Emphasis on Trichogrammatidae
199