Several plant extracts were evaluated against obliquebanded leafroller larvae to determine potent... more Several plant extracts were evaluated against obliquebanded leafroller larvae to determine potential toxicity and antifeedant effects. Two of the plant extracts exhibited contact toxicity; the LC 50 value of Humulus lupulus extract against 3 rd insar larvae was 24.5 μg / insect. In a no choice context, larval survivorship was reduced 23 -57 % after feeding on a meridic pinto bean diet treated with the extracts. Furthermore, average female and male pupal weight was reduced for leafrollers that fed on diet treated with each of the individually-tested extracts at a 4 % concentration (w/w). Incorporation of Bifora radians and H. lupulus into diet deterred larval feeding at a 1 % concentration by weight. H. lupulus and Arctium lappa extracts were deleterious to larvae in each of the bioassay methods conducted, exhibiting toxic, developmental, and antifeedant effects. These two extracts may be promising candidates for further development as botanical insecticides that could potentially substitute broad-spectrum synthetic neurotoxins for leafroller control.
Behavioral and electroantennogram responses of plum curculio, Conotrachelus nenuphar (Herbst) (Co... more Behavioral and electroantennogram responses of plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), adults were tested for several methanolic plant extracts and organically approved insecticides. Plant extracts were evaluated for their potential as antifeedants or oviposition deterrents. These extract responses were also compared to those elicited by the non-neurotoxic, organic irritant-insecticide kaolin clay. Both sexes of plum curculio exhibited antennal response as measured by electroantennogram, which ranged from 0.2 to 1.1 mV, to plant extracts and the organic irritant/insecticide, with the greatest response to the extract of rough cocklebur, Xanthium strumarium L. (1.1 mV). No choice tests were conducted to compare feeding and oviposition by plum curculio on untreated apples or on apples treated with one of the extracts or the insecticide. The insecticide pyrethrum and extracts of X. strumarium and greater burdock, Arctium lappa L., significantly reduce...
... AYHAN GÖKÇE1, LUKASZ L. STELINSKI2*, LARRY J. GUT2 and MARK E. WHALON2 ... Greater success ha... more ... AYHAN GÖKÇE1, LUKASZ L. STELINSKI2*, LARRY J. GUT2 and MARK E. WHALON2 ... Greater success has been recorded with a Western population of obliquebanded leafroller in British Columbia, Canada (Evenden et al., 1999a,b). The females of this Western population ...
Behavioural and electrophysiological responses of reproductive and non-reproductive female round ... more Behavioural and electrophysiological responses of reproductive and non-reproductive female round gobies Neogobius melanostomus to water previously occupied by male round gobies (reproductive male water) were compared. Reproductive females spent more time than nonreproductive females in a tank near the input of water conditioned from reproductive males. Also, reproductive females swam significantly faster than non-reproductive females, suggesting that reproductive male odour may have activated spawning behaviour. Olfactory epithelial field potential measurement (electro-olfactogram, EOG) showed that reproductive male water was a potent olfactory stimulus to reproductive females, but not to non-reproductive females. Reproductive females responded significantly more than non-reproductive females to solidphase (octadecylsilane) extracts of reproductive male water. Also, when these extracts were separated on reverse phase high performance liquid chromatography (HPLC), reproductive females showed noticeably greater responses than non-reproductive females to the fractions that eluted between 30 and 40 min. The behavioural data support the hypothesis that reproductive male round gobies release compounds into the water that attract potential mates. The EOG data indicate that these compounds can be quantitatively extracted from the water and be partially purified by HPLC. The evidence is not sufficient to indicate whether or not the compounds are steroids. The relatively early elution time on HPLC, however, suggests that if these compounds are steroids, then it is more likely that they will be conjugated rather than free steroids.
The contact toxicities of methanol extracts from the nine plant species Hedera helix, Artemisia v... more The contact toxicities of methanol extracts from the nine plant species Hedera helix, Artemisia vulgaris, Xanthium strumarium, Humulus lupulus, Sambucus nigra, Chenopodium album, Salvia officinalis, Lolium temulentum and Verbascum songaricum were tested on the developmental stages of Colorado potato beetle (CPB) (Leptinotarsa decemlineata). About 2 mL of plant extract, 40% (w/w), was applied to the first instar to fourth instar larvae and adult beetles using a Potter spray tower. Most of the tested plant extracts caused relatively low mortality in all the beetle instars. Among the plant extracts, H. lupulus extract was the most toxic to all stages of the insect, except for the adult beetles. Larval mortality ranged from 40% in the fourth instars to 84% in the third instars. In a second series of experiments, dose-response bioassays using H. lupulus extract produced lethal concentration 50 (LC 50 ) values ranging from 10%, 12%, 17% to 46% (w/w) active ingredient (plant material) for instars 1-4, respectively. This increasing mortality trend, however, did not extend to the adult stage where even the maximum dose of 40% plant material did not provide sufficient mortality to allow estimation of a LC 50 . These results demonstrated that the extract from H. lupulus has potential as an active ingredient in biological pesticides developed to manage larval instars of the CPB. The potential uses of this plant extract may be in conventional and organic pest management or as part of a mixture of plant extracts or conventional insecticides. Before extracts can be considered as biological control agents, their impact on natural enemies should be assessed.
Several plant extracts were evaluated against obliquebanded leafroller larvae to determine potent... more Several plant extracts were evaluated against obliquebanded leafroller larvae to determine potential toxicity and antifeedant effects. Two of the plant extracts exhibited contact toxicity; the LC50 value of Humulus lupulus extract against 3rd insar larvae was 24.5 μg / insect. In a no choice context, larval survivorship was reduced 23 - 57 % after feeding on a meridic pinto bean
Several plant extracts were evaluated against obliquebanded leafroller larvae to determine potent... more Several plant extracts were evaluated against obliquebanded leafroller larvae to determine potential toxicity and antifeedant effects. Two of the plant extracts exhibited contact toxicity; the LC 50 value of Humulus lupulus extract against 3 rd insar larvae was 24.5 μg / insect. In a no choice context, larval survivorship was reduced 23 -57 % after feeding on a meridic pinto bean diet treated with the extracts. Furthermore, average female and male pupal weight was reduced for leafrollers that fed on diet treated with each of the individually-tested extracts at a 4 % concentration (w/w). Incorporation of Bifora radians and H. lupulus into diet deterred larval feeding at a 1 % concentration by weight. H. lupulus and Arctium lappa extracts were deleterious to larvae in each of the bioassay methods conducted, exhibiting toxic, developmental, and antifeedant effects. These two extracts may be promising candidates for further development as botanical insecticides that could potentially substitute broad-spectrum synthetic neurotoxins for leafroller control.
Behavioral and electroantennogram responses of plum curculio, Conotrachelus nenuphar (Herbst) (Co... more Behavioral and electroantennogram responses of plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), adults were tested for several methanolic plant extracts and organically approved insecticides. Plant extracts were evaluated for their potential as antifeedants or oviposition deterrents. These extract responses were also compared to those elicited by the non-neurotoxic, organic irritant-insecticide kaolin clay. Both sexes of plum curculio exhibited antennal response as measured by electroantennogram, which ranged from 0.2 to 1.1 mV, to plant extracts and the organic irritant/insecticide, with the greatest response to the extract of rough cocklebur, Xanthium strumarium L. (1.1 mV). No choice tests were conducted to compare feeding and oviposition by plum curculio on untreated apples or on apples treated with one of the extracts or the insecticide. The insecticide pyrethrum and extracts of X. strumarium and greater burdock, Arctium lappa L., significantly reduce...
... AYHAN GÖKÇE1, LUKASZ L. STELINSKI2*, LARRY J. GUT2 and MARK E. WHALON2 ... Greater success ha... more ... AYHAN GÖKÇE1, LUKASZ L. STELINSKI2*, LARRY J. GUT2 and MARK E. WHALON2 ... Greater success has been recorded with a Western population of obliquebanded leafroller in British Columbia, Canada (Evenden et al., 1999a,b). The females of this Western population ...
Behavioural and electrophysiological responses of reproductive and non-reproductive female round ... more Behavioural and electrophysiological responses of reproductive and non-reproductive female round gobies Neogobius melanostomus to water previously occupied by male round gobies (reproductive male water) were compared. Reproductive females spent more time than nonreproductive females in a tank near the input of water conditioned from reproductive males. Also, reproductive females swam significantly faster than non-reproductive females, suggesting that reproductive male odour may have activated spawning behaviour. Olfactory epithelial field potential measurement (electro-olfactogram, EOG) showed that reproductive male water was a potent olfactory stimulus to reproductive females, but not to non-reproductive females. Reproductive females responded significantly more than non-reproductive females to solidphase (octadecylsilane) extracts of reproductive male water. Also, when these extracts were separated on reverse phase high performance liquid chromatography (HPLC), reproductive females showed noticeably greater responses than non-reproductive females to the fractions that eluted between 30 and 40 min. The behavioural data support the hypothesis that reproductive male round gobies release compounds into the water that attract potential mates. The EOG data indicate that these compounds can be quantitatively extracted from the water and be partially purified by HPLC. The evidence is not sufficient to indicate whether or not the compounds are steroids. The relatively early elution time on HPLC, however, suggests that if these compounds are steroids, then it is more likely that they will be conjugated rather than free steroids.
The contact toxicities of methanol extracts from the nine plant species Hedera helix, Artemisia v... more The contact toxicities of methanol extracts from the nine plant species Hedera helix, Artemisia vulgaris, Xanthium strumarium, Humulus lupulus, Sambucus nigra, Chenopodium album, Salvia officinalis, Lolium temulentum and Verbascum songaricum were tested on the developmental stages of Colorado potato beetle (CPB) (Leptinotarsa decemlineata). About 2 mL of plant extract, 40% (w/w), was applied to the first instar to fourth instar larvae and adult beetles using a Potter spray tower. Most of the tested plant extracts caused relatively low mortality in all the beetle instars. Among the plant extracts, H. lupulus extract was the most toxic to all stages of the insect, except for the adult beetles. Larval mortality ranged from 40% in the fourth instars to 84% in the third instars. In a second series of experiments, dose-response bioassays using H. lupulus extract produced lethal concentration 50 (LC 50 ) values ranging from 10%, 12%, 17% to 46% (w/w) active ingredient (plant material) for instars 1-4, respectively. This increasing mortality trend, however, did not extend to the adult stage where even the maximum dose of 40% plant material did not provide sufficient mortality to allow estimation of a LC 50 . These results demonstrated that the extract from H. lupulus has potential as an active ingredient in biological pesticides developed to manage larval instars of the CPB. The potential uses of this plant extract may be in conventional and organic pest management or as part of a mixture of plant extracts or conventional insecticides. Before extracts can be considered as biological control agents, their impact on natural enemies should be assessed.
Several plant extracts were evaluated against obliquebanded leafroller larvae to determine potent... more Several plant extracts were evaluated against obliquebanded leafroller larvae to determine potential toxicity and antifeedant effects. Two of the plant extracts exhibited contact toxicity; the LC50 value of Humulus lupulus extract against 3rd insar larvae was 24.5 μg / insect. In a no choice context, larval survivorship was reduced 23 - 57 % after feeding on a meridic pinto bean
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