Lethal and sublethal effects of fenitrothion and deltamethrin residues on the egg parasitoid Trissolcus grandis (Hymenoptera: Scelionidae).
Effects of fenitrothion and deltamethrin, the most commonly used insecticides in Iran for controlling Eurygaster integriceps Puton (Heteroptera: Scutelleridae), in wheat and barley were assessed on adults and preimaginal stages of egg parasitoid Trissolcus grandis Thompson (Hymenoptera: Scelionidae). Adult parasitoids exposed to field recommended concentrations of the insecticides suffered 100% mortality within 24 h. LC50 values of fenitrothion and deltamethrin for T. grandis were 8.1 and 3.9 microg (AI) /ml, respectively. Both insecticides and the preimaginal stage of exposure had a significant influence on the level of adult emergence from host eggs treated with field recommended rates. Fenitrothion and deltamethrin reduced the emergence rates by 18 and 34.4%, respectively, compared with the control. However, neither insecticide significantly affected the longevity or reproductive capacity of emerged females, or the sex ratio of their progeny. This study revealed that application of these insecticides should be avoided in early season to conserve natural or released populations of T. grandis. Both insecticides seemed to be detrimental to the parasitoid and need to be applied cautiously through season.
Saber
Moosa
M
Department of Plant Protection, Maragheh College of Agriculture, University of Tabriz, Maragheh, Iran.
Hejazi
Mir Jalil
MJ
Kamali
Karim
K
Moharramipour
Saeid
S
D000818:Animals; D005260:Female; D005278:Fenitrothion / Q000009:adverse effects*; D020062:Heteroptera; D001467:Hordeum; D006927:Hymenoptera / Q000187:drug effects* / Q000254:growth & development; D007306:Insecticides / Q000009:adverse effects*; D008297:Male; D009570:Nitriles; D010572:Pest Control, Biological; D011722:Pyrethrins / Q000009:adverse effects*; D014908:Triticum
D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin; D005278:Fenitrothion