by storage system and/or mortality during transportation. Storage of Trichogramma
spp. has received less attention than what is required. In production units, the wasps
are directly transferred to refrigerator in the fifth or sixth day of their life, which
causes to mortality increase and quality reduction. In traditional method, the wasps
are repeatedly exposed to thermal shock and not stored at the right time. The
temperature varies by insectary and therefore determining the right time of storage
is difficult (Attaran and Dadpour-Moghanlou 2011). The similar problem exists in
host egg storage. Abroon et al. (2014) stated that fresh eggs ( 24 h) should be kept
in refrigerator for 24 h. This action has no undesirable effect on parasitism while
prevent host egg hatch. Lengthening the cold storage duration, will result in quality
loss. Several reviews and research papers both in Iran and other countries emphasize
on the importance of the quality of mass-produced Trichogramma in which various
parameters such as longevity, survival rate, sex ratio, fecundity, life table parameters, functional response parameters, host preference etc. have been considered as
quality parameters (see the next subsections).
6.6.1 Longevity
Female longevity is a quality indicator of Trichogramma spp. in field scale (Bigler
1994). It is also an important criterion in preliminary screening of ecotypes or
species of Trichogramma in order to consider in pest management programs
(Vasquez et al. 1997; Gomez et al. 1995, 2005). Longer longevity of a parasitoid
provides more contact fortune to host (Steidle et al. 2001). This may increase the
success of biological control (Nadeem 2010). Different scientists reported different
values for longevity of Trichogramma females ranging from 6 to 9d. The longevity
was 9.19 and 7.27d for T. chilonis on C. cephalonica and H. armigera respectively
(Shirazi 2004), 6.79d for T. pintoi on S. cerealella eggs (Alizadeh and Ebrahimi
2004), 7, 8.12 and 9.16 for T. brassicae on A. kuehniella, S. cerealella and
H. armigera respectively (Vaez et al. 2009).
6.6.2 Fecundity
Fecundity is an important indicator of efficiency of a parasitoid. It directly determines number of parasitized hosts (Roitberg et al. 2001). The average fecundity of
Trichogramma spp. is recorded in laboratory and usually is used to determine quality
of them prior to release. Of course, such criterion may not be adequate in field
condition, because a large number of wasps may die before oviposition (Dutton et al.
1996). Shirazi (2004) stated that T. chilonis has a higher daily fecundity on
C. cephalonica compared to its natural host, H. armigera. Fathipour and DadpourMoghanlou (2003) reported that the fecundity of T. pintoi on A. kuehniella and
S. cerealella eggs were 97.3 and 71.6, respectively. Fecundity of T. brassicae on
208
S. Iranipour and N. Vaez
spp. has received less attention than what is required. In production units, the wasps
are directly transferred to refrigerator in the fifth or sixth day of their life, which
causes to mortality increase and quality reduction. In traditional method, the wasps
are repeatedly exposed to thermal shock and not stored at the right time. The
temperature varies by insectary and therefore determining the right time of storage
is difficult (Attaran and Dadpour-Moghanlou 2011). The similar problem exists in
host egg storage. Abroon et al. (2014) stated that fresh eggs ( 24 h) should be kept
in refrigerator for 24 h. This action has no undesirable effect on parasitism while
prevent host egg hatch. Lengthening the cold storage duration, will result in quality
loss. Several reviews and research papers both in Iran and other countries emphasize
on the importance of the quality of mass-produced Trichogramma in which various
parameters such as longevity, survival rate, sex ratio, fecundity, life table parameters, functional response parameters, host preference etc. have been considered as
quality parameters (see the next subsections).
6.6.1 Longevity
Female longevity is a quality indicator of Trichogramma spp. in field scale (Bigler
1994). It is also an important criterion in preliminary screening of ecotypes or
species of Trichogramma in order to consider in pest management programs
(Vasquez et al. 1997; Gomez et al. 1995, 2005). Longer longevity of a parasitoid
provides more contact fortune to host (Steidle et al. 2001). This may increase the
success of biological control (Nadeem 2010). Different scientists reported different
values for longevity of Trichogramma females ranging from 6 to 9d. The longevity
was 9.19 and 7.27d for T. chilonis on C. cephalonica and H. armigera respectively
(Shirazi 2004), 6.79d for T. pintoi on S. cerealella eggs (Alizadeh and Ebrahimi
2004), 7, 8.12 and 9.16 for T. brassicae on A. kuehniella, S. cerealella and
H. armigera respectively (Vaez et al. 2009).
6.6.2 Fecundity
Fecundity is an important indicator of efficiency of a parasitoid. It directly determines number of parasitized hosts (Roitberg et al. 2001). The average fecundity of
Trichogramma spp. is recorded in laboratory and usually is used to determine quality
of them prior to release. Of course, such criterion may not be adequate in field
condition, because a large number of wasps may die before oviposition (Dutton et al.
1996). Shirazi (2004) stated that T. chilonis has a higher daily fecundity on
C. cephalonica compared to its natural host, H. armigera. Fathipour and DadpourMoghanlou (2003) reported that the fecundity of T. pintoi on A. kuehniella and
S. cerealella eggs were 97.3 and 71.6, respectively. Fecundity of T. brassicae on
208
S. Iranipour and N. Vaez