Comparative study about the sublethal effects of chemical and botanical insecticides on the functional response of Habrobracon hebetor Say (Hym.: Braconidae) to larvae of Ephestia kuehniella Zeller (Lep.: Pyralidae) (original) (raw)
Related papers
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.
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.
Biocontrol
Habrobracon hebetor Say is one of the most important ectoparasitoids of the larval stage of many invasive agricultural pests such as noctuid and pyralid moths. Lethal and sublethal effects of carbaryl and abamectin were assessed on the ectoparasitoid H. hebetor in laboratory conditions. Dose–response bioassays were carried out on immature and adult stages by using dipping and contact residue methods, respectively. LC50 (lethal concentration for 50%) values of carbaryl and abamectin were 31.19 and 4.16 mg a.i. l−1 on larval stage and 12.6 and 4.42 mg a.i. l−1 on adults, respectively. In order to assess the sublethal effects, adult wasps were exposed to an LC30 of each insecticide and then the demographic parameters of live wasps were studied. The results showed that the intrinsic rate of increase (r m ), finite rate of increase (λ), net reproductive rate (R0) and gross reproductive rate (GRR) were significantly affected by the insecticides. The highest and the lowest r m values were 0.23 and 0.17 in control and carbaryl-treated insects, respectively. The sex ratio of H. hebetor offspring was not significantly affected by either insecticide. The results showed that carbaryl had more adverse effects on population parameters of the parasitoid compared to abamectin. Field studies are needed to determine the total effects of the pesticides on H. hebetor.
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.
Toxicity of some new chemistry and conventional insecticides, at different dose rates recommended for field use against Spodoptera litura, and 10% above and below the recommended dose were determined against the adults of a larval parasitoid, Bracon hebetor (Say). Amongst the conventional insecticides, profenofos (Curacron 50EC), chlorpyrifos (Lorsban 40EC), methomyl (Lannate 40SP) and thiodicarb (Larvin 80DP) were selected, while from the new chemistry insecticides, lufenuron (Match 5EC), abamectin (Agrimec 1.8EC), emamectin benzoate (Proclaim 1.9EC), spinosad (Tracer 24SC), indoxacarb (Steward 15EC) and methoxyfenozide (Runner 24SC) were used. The higher dose rate of chlorpyrifos gave 100% mortality in the test insect after 24 hours of application, while at lower and recommended dose rates 100% mortality was recorded after 36 hours of application. Similarly, 100% mortality was also recorded in the adults treated with higher doses of profenofos, recommended and higher dose rate of methomyl and the higher dose rate of thiodicarb after 36hours of application. Mean while, insecticide treatments with emamectin benzoate, abamectin, spinosad, indoxacarb and methoxyfenozide, at different doses, were ranked slightly harmful to harmful after 48 hours of their application.
Laboratory evaluation of certain bio-pesticides against the larvae of Helicoverpa armigera Hubner
LEGUME RESEARCH, 2016
Applications of Helicoverpa armigera Nuclear Polyhedrosis Virus (HaNPV), Quinalphos, Bacillus thuringiensis kurstaki (Btk) and Beauveria bassiana (B.b.) as full doses gave hundred percent larval mortality to the test insect, 2 nd instar larvae of Helicoverpa armigera. Treatment combinations containing half doses of HaNPV + Btk, HaNPV + B.b., HaNPV + Quinalphos, Btk + B.b., Btk + Quinalphos, B.b.+ Quinalphos, also gave cent percent larval death. Azadirachtin as half dose of application was found to be least effective (50%). However, all the treatment combinations were found effective over the untreated control.
Journal of Crop Protection, 2018
Habrobracon hebetor Say (Hymenoptera: Braconidae) is one of the major parasitoids which is used against various lepidopteran larvae in Iran. Due to extensive application of chemical pesticides in farms, study of their side effects on natural enemies is necessary. Therefore, in this study, side-effects of two prevalent insecticides, NeemAzal and Takumi (at dosage 2000 mg/l and 437.5mg/l, respectively), on functional response of H. hebetor to different densities of 5 instar larvae of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) were evaluated in laboratory conditions. Host densities of 2, 4, 8, 16, 32 and 64 were randomly exposed to selected treated females of H. hebetor in 8 cm Petri dishes. Ten replications were conducted for each host density. The control was treated with water. The data were analyzed using logistic regression to find functional response type and non-linear regression to estimate functional response parameters. The results revealed a type ΙΙ response for all...
American Journal of Plant Sciences, 2014
Insecticides from different chemical groups were tested by laboratory bioassay to verify the percentage mortality of Helicoverpa armigera (Hubner 1808) (Lepidoptera: Noctuidae). The experiment was conducted in the Crop Science laboratory-Prof. CinobelinaElvas Campus-UFPI, Bom Jesus, PI, from January to June, 2013. The populations utilized came from the University's own insect breeding laboratories. Third instar larvae of H. armigera were used to conduct the bioassay. The experimental design was fully randomized, with 13 treatments and four replications. Five larvae were used per replication, with 12 insecticides from 9 different chemical groups and a control. Each treatment consisted of three doses. The methods of application used were topical contact and ingestion in artificial diet. According to the results the percentage mortality of H. armigera larvae varied among the treatments. The results demonstrated that chlorpyrifos and spinosad were effective against third instar H. armigera larvae both on contact and by ingestion. Flubendiamide, acephate, methomyl, Bacillus thuringiensis, dimethoate, chlorantraniliprole and fipronil had good responses to control of H. armigera.
European Journal of Sustainable Development
The present study showed the acute toxicity and the effects of two widely used insecticides Profenofos, Cyfluthrin and the IGR (Runner) on the activity of the larval parasitoid, Bracon hebetor (Hymenoptera: Braconidae), a natural enemy of many insect pests. The direct application of the tested insecticides induced drastic effect on the adult male and/or female parasitoid, leading to 100% mortality within 24-48 hours post treatment for Cyfluthrin, 7 days post treatment for Runner treatment and 6 days post treatment for Profenofos. The indirect effect bioassays were conducted by applying five concentrations of each insecticide to the artificial diet of the host larvae (Galleria mellonella). The least toxic one to B. hebetor was Profenofos followed by Runner. While Cyfluthrin was the most toxic one which was dangerous on all life stages of B. hebetor, influencing the number of laid eggs by the parasitoid, percent of pupation and leading to failure of adult emergence.
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.