The cochineal, Dactylopius opuntiae, has recently become the main pest that damages the prickly cactus, Opuntia ficus-indica, plants in Morocco. The control methods in which pesticides are used and applied weekly, hav...The cochineal, Dactylopius opuntiae, has recently become the main pest that damages the prickly cactus, Opuntia ficus-indica, plants in Morocco. The control methods in which pesticides are used and applied weekly, have generated phytotoxicity, poisoning and high residuality in fresh nopal, which also prevents its commercialization in international markets and the constant risk to human and animal health. Therefore, the use of less aggressive products with a low impact on the environment and is sustainable for the crop, has been introduced without an obvious strategy for gradual control of the insect. This study was conducted to evaluate the effects of Beta vulgaris subsp., Eucalyptus torquata and Cedrus atlantica plant extracts (Eucalyptus leaves, small pieces of beet and Cedrus leaves powdered and macerated in 100 ml of distilled water for 72 h) for controlling of D. opuntiae under laboratory and field conditions. The results show that these extracts constitute a viable alternative for the control of wild cochineal in the nopal. A gradual reduction of cochineal populations was obtained, until after the third application with these extracts, with biological effectiveness of up to 90%. The findings of our study indicate that Beta vulgaris subsp., plant extracts could be used in the development and implementation of a biological control program against D. opuntiae under field conditions.展开更多
In this experiment carried out on Caribbean chili pepper plants(Capsicum chinensis),the bio-insecticide azadirachtin in combination with an NPK fertilizer proved to have a greater lethal impact on the larvae of Aedes ...In this experiment carried out on Caribbean chili pepper plants(Capsicum chinensis),the bio-insecticide azadirachtin in combination with an NPK fertilizer proved to have a greater lethal impact on the larvae of Aedes albopictus than each substance on its own.This synergistic effect is noticeably important when both inputs are sprayed directly on the leaves of the plant(foliar application).While the plants treated with azadirachtin or NPK alone cause a 33.6%and 36.4%mortal-ity respectively of the Ae.albopictus larvae,the combination of the two inputs induces a 74.4%mortality on the mosquito larvae.To account for this synergistic effect phenomenon inside the plant,the azadirachtin+NPK combination most likely interacts with the capsaicinoid compounds naturally produced by the plant.Not only does this study carried out on azadirachtin reveal major results but the methodology itself offers a most interesting approach on how to boost the agricultural inputs within the plants.As a matter of fact,this research axis demands developing since the control of pests harmful to men has been dramatically lacking insecticide molecules acting on new targets over the past three decades.展开更多
Toxins from spider venom Crossopriza lyoni were subjected to purify on a Sepharose CL-6B 200 column. These were investigated for its antibacterial and antifungal activity against 13 infectious microbial pathogenic str...Toxins from spider venom Crossopriza lyoni were subjected to purify on a Sepharose CL-6B 200 column. These were investigated for its antibacterial and antifungal activity against 13 infectious microbial pathogenic strains. Antimicrobial susceptibility was determined by using paper disc diffusion and serial micro-dilution assays. Triton X-100 (0.1%) proved to be a good solubilizing agent for toxin/proteins. Higher protein solubilization was observed in the supernatant than in the residue, except TCA. The elution pattern of purified and homogenized sting glands displayed two major peaks at 280 nm. First one was eluted in fraction no. 43 - 51 while second one after fraction no. 61 - 90. From gel filtration chromatography total yield of protein obtained was 67.3%. From comparison of gel chromatographs eluted toxins peptide molecular weight was ranging from 6.2 - 64 kD. Toxin peptides have shown lower MIC values i.e. 7.5 - 15 μg/ml against K. pneumoniae, E. coli, L. acidophilus, B. cereus;against S. aureus and M. luteus that the broad spectrum antibiotics i.e. tetracycline and ampicillin. In tests, larger inhibition zone diameter was obtained in comparison to control. Diameter of inhibition zones obtained in spider toxins at a concentration range of 197.12 - 0.96 g/ml for E. coli was 17.86 ± 0.21, Bacillus cereus 19.13 ± 0.21, L. acidophilus 16.83 ± 0.25, Micrococcus luteus 18.46 ± 0.17, S. aeurus 16.23 ± 0.19, Klebsiella pneumoniae 21.83 ± 0.16, Salmonella typhi 16.16 ± 0.21, Vibrio cholera 18.66 ± 0.21, Pseudomonas aeruginosa 18.66 ± 0.21, Aspergillus niger 22.9 ± 0.24, Candida albicans 24.66 ± 0.28, Rhizopus stolonifer 21.1 ± 0.16. Spider toxins generate cytotoxic effect on bacterial cells that results in heavy cell death. No doubt spider toxins can be used as alternate of broad spectrum antibiotics.展开更多
Cotton leaf worm, Spodoptera littoralis, is considered one of the most common arthropod pests that contribute to crop devastation of cotton. Previously, agricultural pests were controlled through the application of ch...Cotton leaf worm, Spodoptera littoralis, is considered one of the most common arthropod pests that contribute to crop devastation of cotton. Previously, agricultural pests were controlled through the application of chemical insecticides. However, insecticide-resistant insect populations emergence, as well as increasing concerns about the environmental and human health risks. Venomous animals introduce valuable sources of bioactive compounds which are employed for defence. Some of these toxins have high phyletic specificity, making them appropriate for use in IPM programs. This study aims to test the insecticidal effects of Polistes dominulus and Apis mellifera venoms. Crude venoms were examined for their insecticidal effect against cotton leaf worms by four different application methods including: leaf dipping, integument dropping, spraying, and injection. The data demonstrated a strong response to purified (Polistes dominulus) venom at an initial time than that of honey bee (Apis mellifera) which increases response with increasing the dose and the time interval. A dosage of 0.015 - 0.16 ml of both venoms had notably varied in LD<sub>50</sub> values on Spodoptera littoralis that showed higher wasp venom toxicity. Cotton leaf worms showed more susceptibility and mortality to the Polistes sp. venom than that of honey bees.展开更多
文摘The cochineal, Dactylopius opuntiae, has recently become the main pest that damages the prickly cactus, Opuntia ficus-indica, plants in Morocco. The control methods in which pesticides are used and applied weekly, have generated phytotoxicity, poisoning and high residuality in fresh nopal, which also prevents its commercialization in international markets and the constant risk to human and animal health. Therefore, the use of less aggressive products with a low impact on the environment and is sustainable for the crop, has been introduced without an obvious strategy for gradual control of the insect. This study was conducted to evaluate the effects of Beta vulgaris subsp., Eucalyptus torquata and Cedrus atlantica plant extracts (Eucalyptus leaves, small pieces of beet and Cedrus leaves powdered and macerated in 100 ml of distilled water for 72 h) for controlling of D. opuntiae under laboratory and field conditions. The results show that these extracts constitute a viable alternative for the control of wild cochineal in the nopal. A gradual reduction of cochineal populations was obtained, until after the third application with these extracts, with biological effectiveness of up to 90%. The findings of our study indicate that Beta vulgaris subsp., plant extracts could be used in the development and implementation of a biological control program against D. opuntiae under field conditions.
文摘In this experiment carried out on Caribbean chili pepper plants(Capsicum chinensis),the bio-insecticide azadirachtin in combination with an NPK fertilizer proved to have a greater lethal impact on the larvae of Aedes albopictus than each substance on its own.This synergistic effect is noticeably important when both inputs are sprayed directly on the leaves of the plant(foliar application).While the plants treated with azadirachtin or NPK alone cause a 33.6%and 36.4%mortal-ity respectively of the Ae.albopictus larvae,the combination of the two inputs induces a 74.4%mortality on the mosquito larvae.To account for this synergistic effect phenomenon inside the plant,the azadirachtin+NPK combination most likely interacts with the capsaicinoid compounds naturally produced by the plant.Not only does this study carried out on azadirachtin reveal major results but the methodology itself offers a most interesting approach on how to boost the agricultural inputs within the plants.As a matter of fact,this research axis demands developing since the control of pests harmful to men has been dramatically lacking insecticide molecules acting on new targets over the past three decades.
文摘Toxins from spider venom Crossopriza lyoni were subjected to purify on a Sepharose CL-6B 200 column. These were investigated for its antibacterial and antifungal activity against 13 infectious microbial pathogenic strains. Antimicrobial susceptibility was determined by using paper disc diffusion and serial micro-dilution assays. Triton X-100 (0.1%) proved to be a good solubilizing agent for toxin/proteins. Higher protein solubilization was observed in the supernatant than in the residue, except TCA. The elution pattern of purified and homogenized sting glands displayed two major peaks at 280 nm. First one was eluted in fraction no. 43 - 51 while second one after fraction no. 61 - 90. From gel filtration chromatography total yield of protein obtained was 67.3%. From comparison of gel chromatographs eluted toxins peptide molecular weight was ranging from 6.2 - 64 kD. Toxin peptides have shown lower MIC values i.e. 7.5 - 15 μg/ml against K. pneumoniae, E. coli, L. acidophilus, B. cereus;against S. aureus and M. luteus that the broad spectrum antibiotics i.e. tetracycline and ampicillin. In tests, larger inhibition zone diameter was obtained in comparison to control. Diameter of inhibition zones obtained in spider toxins at a concentration range of 197.12 - 0.96 g/ml for E. coli was 17.86 ± 0.21, Bacillus cereus 19.13 ± 0.21, L. acidophilus 16.83 ± 0.25, Micrococcus luteus 18.46 ± 0.17, S. aeurus 16.23 ± 0.19, Klebsiella pneumoniae 21.83 ± 0.16, Salmonella typhi 16.16 ± 0.21, Vibrio cholera 18.66 ± 0.21, Pseudomonas aeruginosa 18.66 ± 0.21, Aspergillus niger 22.9 ± 0.24, Candida albicans 24.66 ± 0.28, Rhizopus stolonifer 21.1 ± 0.16. Spider toxins generate cytotoxic effect on bacterial cells that results in heavy cell death. No doubt spider toxins can be used as alternate of broad spectrum antibiotics.
文摘Cotton leaf worm, Spodoptera littoralis, is considered one of the most common arthropod pests that contribute to crop devastation of cotton. Previously, agricultural pests were controlled through the application of chemical insecticides. However, insecticide-resistant insect populations emergence, as well as increasing concerns about the environmental and human health risks. Venomous animals introduce valuable sources of bioactive compounds which are employed for defence. Some of these toxins have high phyletic specificity, making them appropriate for use in IPM programs. This study aims to test the insecticidal effects of Polistes dominulus and Apis mellifera venoms. Crude venoms were examined for their insecticidal effect against cotton leaf worms by four different application methods including: leaf dipping, integument dropping, spraying, and injection. The data demonstrated a strong response to purified (Polistes dominulus) venom at an initial time than that of honey bee (Apis mellifera) which increases response with increasing the dose and the time interval. A dosage of 0.015 - 0.16 ml of both venoms had notably varied in LD<sub>50</sub> values on Spodoptera littoralis that showed higher wasp venom toxicity. Cotton leaf worms showed more susceptibility and mortality to the Polistes sp. venom than that of honey bees.
