Comparative study of the population level effects of carbaryl and abamectin on larval ectoparasitoid Habrobracon hebetor Say (Hymenoptera: Braconidae) (original) (raw)
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Toxicity of some commonly used pesticides on different developmental stages of a biological control agent, Habrobracon hebetor (Say) (Hymenoptera: Braconidae), were investigated in the laboratory. Persistent toxicity of tested pesticides on the adult stage of parasitoid was also determined. The effects of pesticides on immature stages of parasitoid were tested by dipping H. hebetor larvae and pupae in pesticide solution at recommended concentrations. The adult wasps were exposed to field-recommended concentration of the pesticides on glass plates. Chlorpyrifos significantly reduced adult emergence when parasitoid larvae or pupae were treated with fieldrecommended concentration. Cypermethrin and iprodion+carbendazim also had a significant adverse effect on parasitoid emergence during the larval stage. Among all the tested pesticides, cypermethrin and chlorpyrifos exhibited the highest toxicity to adult wasps. Persistency test showed that chlorpyrifos and cypermethrin were "moderately persistent" and "slightly persistent", respectively. Other pesticides were classified as "little persistent". The implications of these results for the integration of biological and chemical control methods are discussed.
نامة انجمن حشره شناسی ایران, 2008
Insect growth regulators and spinosyns which are physiologically and ecologically selective, respectively, have been investigated as replacements or complements to non-selective conventional insecticides. The effects of diflubenzuron, hexaflumuron, profenofos, spinosad and thiodicarb were assessed on the 1 st instars of cotton bollworm, Helicoverpa armigera (Hübner) using dietary and leaf disc bioassay methods. Based on modes of action of the insecticides tested, the mortalities were recorded after 24 h in profenofos, thiodicarb and spinosad experiments and after 120 h in hexaflumuron and diflubenzuron treatments. The LC50 values for diflubenzuron, hexaflumuron, profenofos, spinosad and thiodicarb in dietary method were 595.05, 0.31, 3.69, 0.13 and 11.2 mg ai/L; and in leaf disc method, they were >2000, 0.46, 9.55, 0.2 and 15.52 mg ai/L, respectively. The effects of these insecticides on adult Habrobracon hebetor Say, an ectoparasitoid of cotton bollworm were tested using residual method. The mortalities were recorded after 24 h in all treatments. The LC50 values for diflubenzuron, hexaflumuron, profenofos, spinosad and thiodicarb for females were >2000, >2000, 12.44, 15.64 and 81.04 mg ai/L, respectively and for males, they were >2000, >2000, 6.91, 11.73 and 40.39 mg ai/L, respectively. In this study spinosad and hexaflumuron seemed to be more useful than the other insecticides due to their higher toxicity to H. armigera and lower toxicity to H. hebetor.
Note: Toxicity of some insecticides onBracon hebetor under laboratory conditions
Phytoparasitica, 2006
Insecticides which were environmentally friendly and the least toxic, were screened against a laboratory strain of Bracon hebetor (Say) (Hymenoptera: Braconidae) for their suitability for release in IPM of cotton. Concentrations ranging from 1 to 1000 ppm of the formulated insecticides in acetone were applied in glass vials and also by a leaf method, whereby cotton leaves were dipped in aqueous solutions of the same concentrations of insecticides. Adult parasitoids were exposed in both methods. According to the LCso at 24 h exposure, Acyhalothrin and spinosad were the most (7 and 5 ppm) and least (263 and 225 ppm) toxic in the vial and the leaf method, respectively, to B. hebetor. The possible use of the parasitoid for IPM of cotton is discussed.
International Journal of Pest Management, 2020
In this research, we evaluated sublethal effects of five commercial insecticides of fenvalerate, propargite, buprofezin, dayabon and palizin which are used in chemical control of target pests of Habrobracon hebetor Say (an idiobiont and gregarious ectoparasitoid), on the functional response of this important biocontrol agent. First, 80 mated females of H. hebetor were treated by LC 30 of selected insecticides for 24 h. Then, among them six wasps were selected and introduced to different densities of Ephestia kuehniella Zeller larvae (flour moth, an economical stored pest of cereals) for 24 h. The regression analyses based on Holling model indicated the functional response type II in the control, palizin and buprofezin and type III in fenvalerate, propargite and dayabon. Moreover, the highest and lowest attack rates were obtained in palizin and fenvalerate treatments, respectively. In addition, the treated wasps by dayabon and fenvalerate showed the shortest and longest handling times, respectively. Accordingly, palizin and dayabon due to the lowest negative effects on H. hebetor are compatible insecticides for combination with this biocontrol agent in integrated pest management.
Effects of methoxyfenozide and pyridalyl on the larval ectoparasitoid Habrobracon hebetor
Journal of Pest Science, 2013
Habrobracon hebetor Say (Hymenoptera: Braconidae) is an ectoparasitoid that is used for inundative biological control of various lepidopteran insect pests. Lethal and sublethal effects of two biorational insecticides, methoxyfenozide and pyridalyl, were evaluated on H. hebetor under laboratory conditions. The adults were exposed to dry insecticide residues that were applied on glass plates. Bioassays showed that the LC 50 values of methoxyfenozide and pyridalyl were 155 and 1,226 lg a.i./ml, respectively. The LT 50 values of methoxyfenozide and pyridalyl were 2.1 and 3.3 days, respectively. The effects of methoxyfenozide and pyridalyl on larvae were tested using a dip method with field-recommended concentrations of either insecticide. The emergence rates were reduced by 24.4 and 29.3 % for methoxyfenozide and pyridalyl treatments, respectively. In order to assess the sublethal effects of low-lethal concentrations of methoxyfenozide and pyridalyl, adult wasps were exposed to the LC 30 concentration of each insecticide, and demographic parameters of live wasps were recorded. Exposure of adults to low-lethal concentrations (LC 30) negatively affected the fecundity, fertility, and sex ratio, and also the intrinsic rate of increase (r m), finite rate of increase (k), generation time (T), and doubling time (DT). The longevity and net reproductive rate (R 0) of H. hebetor were not affected by sublethal exposure to these insecticides. The results showed that despite low acute toxicities of both insecticides on larval and adult stages of H. hebetor, they may negatively affect the population of the parasitoid and interfere in IPM programs.
Journal of Economic Entomology, 2014
Habrobracon hebetor Say is an ectoparasitoid of larval stage of various lepidopteran pests. Lethal and sublethal effects of azadirachtin and cypermethrin were evaluated on adult and preimaginal stages of H. hebetor under laboratory conditions. Contact exposure bioassays with adults indicated that the lethal concentration (LC 50) of two commercial azadirachtin-containing formulations, NeemGuard and BioNeem, were 43.5 and 10.2 g a.i./ml, respectively. The LC 50 of cypermethrin was 5.4 g a.i./ml. When larval stage of H. hebetor was exposed to these insecticides with a Þeld recommended concentration of NeemGuard, BioNeem, or cypermethrin by a dip protocol, the emergence rate was reduced by 39.0, 36.6, and 97.6%, respectively. To assay the sublethal effects of these insecticides, adult wasps were exposed to an LC 30 concentration of the insecticides, and then demographic parameters of the surviving wasps were determined. Fecundity, fertility, and parameters including the intrinsic rate of increase (r m) were affected negatively. The r m values following exposure to NeemGuard, BioNeem, cypermethrin, or mock treatment were 0.143, 0.149, 0.160, and 0.179, respectively, female offspring per female per day, respectively. The current study showed that cypermethrin had more acute toxicity on larval and adult stages of H. hebetor compared with azadirachin. The commercial formulations of azadirachtin and cypermethrin negatively affected most of the life table parameters of the parasitoid. SemiÞeld and Þeld studies are needed for obtaining more applicable results on combining H. hebetor and the tested insecticides for an integrated pest management-based strategy for crop protection.
Journal of Economic Entomology, 2014
Habrobracon hebetor Say is an ectoparasitoid of larval stage of various lepidopteran pests. Lethal and sublethal effects of azadirachtin and cypermethrin were evaluated on adult and preimaginal stages of H. hebetor under laboratory conditions. Contact exposure bioassays with adults indicated that the lethal concentration (LC 50 ) of two commercial azadirachtin-containing formulations, NeemGuard and BioNeem, were 43.5 and 10.2 g a.i./ml, respectively. The LC 50 of cypermethrin was 5.4 g a.i./ml. When larval stage of H. hebetor was exposed to these insecticides with a Þeld recommended concentration of NeemGuard, BioNeem, or cypermethrin by a dip protocol, the emergence rate was reduced by 39.0, 36.6, and 97.6%, respectively. To assay the sublethal effects of these insecticides, adult wasps were exposed to an LC 30 concentration of the insecticides, and then demographic parameters of the surviving wasps were determined. Fecundity, fertility, and parameters including the intrinsic rate of increase (r m ) were affected negatively. The r m values following exposure to NeemGuard, BioNeem, cypermethrin, or mock treatment were 0.143, 0.149, 0.160, and 0.179, respectively, female offspring per female per day, respectively. The current study showed that cypermethrin had more acute toxicity on larval and adult stages of H. hebetor compared with azadirachin. The commercial formulations of azadirachtin and cypermethrin negatively affected most of the life table parameters of the parasitoid. SemiÞeld and Þeld studies are needed for obtaining more applicable results on combining H. hebetor and the tested insecticides for an integrated pest management-based strategy for crop protection.
Journal of Economic Entomology, 2014
Habrobracon hebetor Say is an ectoparasitoid of larval stage of various lepidopteran pests. Lethal and sublethal effects of azadirachtin and cypermethrin were evaluated on adult and preimaginal stages of H. hebetor under laboratory conditions. Contact exposure bioassays with adults indicated that the lethal concentration (LC 50) of two commercial azadirachtin-containing formulations, NeemGuard and BioNeem, were 43.5 and 10.2 g a.i./ml, respectively. The LC 50 of cypermethrin was 5.4 g a.i./ml. When larval stage of H. hebetor was exposed to these insecticides with a Þeld recommended concentration of NeemGuard, BioNeem, or cypermethrin by a dip protocol, the emergence rate was reduced by 39.0, 36.6, and 97.6%, respectively. To assay the sublethal effects of these insecticides, adult wasps were exposed to an LC 30 concentration of the insecticides, and then demographic parameters of the surviving wasps were determined. Fecundity, fertility, and parameters including the intrinsic rate of increase (r m) were affected negatively. The r m values following exposure to NeemGuard, BioNeem, cypermethrin, or mock treatment were 0.143, 0.149, 0.160, and 0.179, respectively, female offspring per female per day, respectively. The current study showed that cypermethrin had more acute toxicity on larval and adult stages of H. hebetor compared with azadirachin. The commercial formulations of azadirachtin and cypermethrin negatively affected most of the life table parameters of the parasitoid. SemiÞeld and Þeld studies are needed for obtaining more applicable results on combining H. hebetor and the tested insecticides for an integrated pest management-based strategy for crop protection.
Journal of Plant Protection Research, 2013
The functional response is a behavioral phenomena defined as the relation between the parasitized host per each parasitoid and host density. This phenomenon can be useful in assessing parasitoid efficiency for the biological control of the host. Parasitoid wasps are most important insects and they play a significant role in the natural control of pests via their parasitism activities. In this study, the effects of diazinon and malathion were evaluated on the functional response of Habrobracon hebetor Say to different densities of last instar larvae of Anagasta kuehniella Zeller. Young adult females (< 24 h old) of the parasitoid were exposed to LC 30 values of pesticides. Host densities of 2, 4, 8, 16, 32, and 64 were offered, to treated young females for 24 h in 10 cm Petri dishes. At this point, the parasitism data were recorded. The experiments were conducted in eight replications. The functional response was type Ш in the control and insecticide treatments. Searching efficiency in the control, diazinon and malathion-treated wasps were 0.008±0.002, 0.003±0.002, and 0.004±0.002 h -1 , handling times were 1.38±0.1, 7.95±0.91, and 6.4±0.81 h, respectively. Diazinon and malathion had the highest and the lowest effect on searching efficiency of H. hebetor, respectively. After conducting advanced field studies, it was found that malathion may be used as a compatible chemical material with biological control agent in IPM programs.