smaller-scale facilities are advantages (Zomorrodi 1962). However, the main problem in natural rearing method has been obligatory reproductive diapause of sunn pest
and annual life cycle of the pest. This means that the host is available for a short
period (at most two months). This is also a restriction in laboratory studies on
parasitoids. One can partially overcome such a restriction by some foresees. For
example, one can search for adults in the resting site during January–March. In this
period, reproductive diapause terminates and bugs begin to oviposit if they are
maintained in warm condition. They need only spend a short pre-oviposition period
as long as one week (Martin et al. 1969; Abdollahy 1989; Iranipour 2008). Thus,
eggs will be available three months before arrival of immigrant bugs. Another way
for overcoming the problem is collecting from different regions with different
thermal patterns. A three-month difference is present among different regions in
terms of seasonal activity of sunn pest (Radjabi 2000). For example, one can sweep
bugs upon cereal ears during February in southern regions of country such as Jiroft
(Kerman province), Darab (Fars province) or Saravan (Sistan-and-Baluchestan
province). On the other hand in colder regions such as Ardabil and Meshkinshahr
(Ardabil province) and Faridan (Isfahan province), bugs only leave their resting sites
during May. In both areas, the duration of reproductive phase takes two months. A
third way to overcome the problem has been manipulating of diapause by JH mimics
such as pyriproxyfen (Zarnegar and Noori 2006). Unfortunately, this method has not
been entirely flawless. Parasitoids can attack and successfully develop in the majority of eggs deposited by JH-treated bugs (Iranipour 1996), but bug embryo cannot
develop (Zarnegar and Noori 2006). In some cases, using factitious hosts may be a
solution. Safavi (1973) had limited studies on the possibility of parasitoid rearing
upon Aelia, Dolycoris and Brachynema species, but unfortunately, no report of
success degree or probable obstacles has published. Some attempts also were done
for the rearing of egg parasitoids on Graphosoma lineatum (Asgari 1995; Shahrokhi
et al. 1998), Podisus maculiventris (Allahyari et al. 2002) and Andralus spinidens
(F.) (Mohaghegh-Neyshabouri and Amir-Maafi 2000; Najafi-Navaei et al. 2000).
None of these hosts has been comparable to a target host. P. maculiventris is not a
native species of Iran fauna and no effort was done for an establishment in Iran. It
just introduced from Canada and investigated in the laboratory for a short time.
Among other species, G. lineatum has been a promising factitious host. An easy way
for rearing, the absence of diapause, the suitable rate of development and reproduction, and high acceptance by parasitoids are positive properties that make this species
a good candidate for biological control programs. Nevertheless, inundative release
programs of late 1940s and 1950s finally were abandoned for unknown reasons. No
published article explained the reasons for such avoidance of inundation. Afterward,
only some restricted efforts in research scale were done for using these parasitoids
(T. vassilievi in Asgari’s 2011 study with acceptable results) in biocontrol programs.
Nowadays chemical control is the main control measurement used against sunn
pests. In the last 10 years, governmental incorporation in applications using aircraft
were replaced by farmer applications.
8 Superfamily Platygastroidea: Natural Enemies of True Bugs, Moths, Other. . .
313
and annual life cycle of the pest. This means that the host is available for a short
period (at most two months). This is also a restriction in laboratory studies on
parasitoids. One can partially overcome such a restriction by some foresees. For
example, one can search for adults in the resting site during January–March. In this
period, reproductive diapause terminates and bugs begin to oviposit if they are
maintained in warm condition. They need only spend a short pre-oviposition period
as long as one week (Martin et al. 1969; Abdollahy 1989; Iranipour 2008). Thus,
eggs will be available three months before arrival of immigrant bugs. Another way
for overcoming the problem is collecting from different regions with different
thermal patterns. A three-month difference is present among different regions in
terms of seasonal activity of sunn pest (Radjabi 2000). For example, one can sweep
bugs upon cereal ears during February in southern regions of country such as Jiroft
(Kerman province), Darab (Fars province) or Saravan (Sistan-and-Baluchestan
province). On the other hand in colder regions such as Ardabil and Meshkinshahr
(Ardabil province) and Faridan (Isfahan province), bugs only leave their resting sites
during May. In both areas, the duration of reproductive phase takes two months. A
third way to overcome the problem has been manipulating of diapause by JH mimics
such as pyriproxyfen (Zarnegar and Noori 2006). Unfortunately, this method has not
been entirely flawless. Parasitoids can attack and successfully develop in the majority of eggs deposited by JH-treated bugs (Iranipour 1996), but bug embryo cannot
develop (Zarnegar and Noori 2006). In some cases, using factitious hosts may be a
solution. Safavi (1973) had limited studies on the possibility of parasitoid rearing
upon Aelia, Dolycoris and Brachynema species, but unfortunately, no report of
success degree or probable obstacles has published. Some attempts also were done
for the rearing of egg parasitoids on Graphosoma lineatum (Asgari 1995; Shahrokhi
et al. 1998), Podisus maculiventris (Allahyari et al. 2002) and Andralus spinidens
(F.) (Mohaghegh-Neyshabouri and Amir-Maafi 2000; Najafi-Navaei et al. 2000).
None of these hosts has been comparable to a target host. P. maculiventris is not a
native species of Iran fauna and no effort was done for an establishment in Iran. It
just introduced from Canada and investigated in the laboratory for a short time.
Among other species, G. lineatum has been a promising factitious host. An easy way
for rearing, the absence of diapause, the suitable rate of development and reproduction, and high acceptance by parasitoids are positive properties that make this species
a good candidate for biological control programs. Nevertheless, inundative release
programs of late 1940s and 1950s finally were abandoned for unknown reasons. No
published article explained the reasons for such avoidance of inundation. Afterward,
only some restricted efforts in research scale were done for using these parasitoids
(T. vassilievi in Asgari’s 2011 study with acceptable results) in biocontrol programs.
Nowadays chemical control is the main control measurement used against sunn
pests. In the last 10 years, governmental incorporation in applications using aircraft
were replaced by farmer applications.
8 Superfamily Platygastroidea: Natural Enemies of True Bugs, Moths, Other. . .
313