The ectoparasitoid wasp, Habrobracon hebetor (Say, 1836) (Hym.: Braconidae) is one of the most important natural enemies of many pests in Iran. In this study, the effects of sublethal concentrations of malathion (LC 10 and LC 25 ) on biological parameters of the adult wasp including parasitism percentage, male production and longevity of the parasitoid in different growth stages (larvae, pupae and adult) were investigated. The experiments were conducted at 26 ± 1 °C, 60 ± 5 % RH, and 16L:8D h photoperiods. The effect of sublethal concentrations of malathion on adults was determined by exposure of wasp to insecticide, and in the case of larvae and pupae, immersion method was used. Based on the results, with the increase of toxic dose, the percentage of parasitism in adult decreased from 95.6 5% to 87.78 %, compared to the control treatment. Male production increased from 22.73 % in control to 56.38 % at LC 25 concentration. Also, the percentage of parasitism of the malathion-impregnated wasp larvae decreased from 87.78 to 22.92%, compared to the control treatment. Male production from 30.94 % in the control increased to 39.63 % at the LC 25 concentration. In addition, the percentage of parasitism in the wasp pupae impregnated with malathion was reduced from 93.33 to 88.89 %, respectively. Male production increased from 22.98 in the control to 37.23 % in the LC 25 concentration. The data showed that pupae were more susceptible to sublethal concentrations than the larvae.
IZVLEČEKUČINEK SUBLETALNIH KONCENTRACIJ MALATIONA NA NEKATERE BIOLOŠKE PARAMETRE EKTOPARAZITSKE OSICE Habrobracon hebetor (Say, 1836) Ektoparazitska osica Habrobracon hebetor (Say, 1836), (Hymenoptera: Braconidae) je eden izmed najpomembnejših naravnih sovražnikov mnogih škodljivih žuželk v Iranu. V raziskavi so bili preučevani učinki subletalnih koncentracij malationa (LC 10 in LC 25 ) na biološke parametre odraslih osic vključno z odstotkom parazitiranja, razvojem samcev in življenjsko dobo parazitoida v različnih razvojnih štadijih (ličinke, bube in imagi). Poskus je bil izveden pri 26 ± 1 °C, 60 ± 5 % RH in osvetlitvi 6 : 8 dan/noč. Učinek subletalnih koncentracij malationa na image je bil določen z izpostavitvijo osic insekticidu, v primeru ličink in bub je bila uporabljena metoda potapljanja. Rezultati so pokazali, da je z naraščanjem koncentracije insekticida odstotek parazitiranja upadel iz 95,65 % na 87,78 % v primerjavi s kontrolo. Razvoj samcev se je iz 22,73 % v kontroli povečal na 56,38 % pri koncentraciji LC 25 . Tudi odstotek parazitiranja z malationom impregniranih ličink osic se je zmanjšal iz 87,78 % na 22,92 % v primerjavi s kontrolo. Razvoj samcev se je iz 30,94 % v kontroli povečal na 39,63 % pri koncentraciji LC 25 . Dodatno se je odstotek parazitiranja bub impregniranih z malationom zmanjšal iz 93,33 na 88,89 %. Razvoj samcev se je povečal iz 22.98 v kontroli na 37,23 % pri koncentraciji LC 25 . Podatki so pokazali, da so bile bube bolj občutljive na subletalne koncentracije kot ličinke. Ključne besede: malation; subletalna k...