Urticae Koch (urticae + koch)

Distribution by Scientific Domains

Kinds of Urticae Koch

  • Tetranychu urticae koch

  • Selected Abstracts

    Effect of vegetation management on autumn dispersal of Tetranychus urticae (Acari: Tetranychidae) from tomato

    E. D. Meck
    Abstract Autumn dispersal of twospotted spider mite (Tetranychus urticae Koch) from tomato to overwintering host plants was studied in field experiments during 2004,2006. Three vegetation management strategies (herbicide, cultivation and no vegetation control) were established around mite-infested, senescing tomato plants. Tetranychus urticae dispersal was monitored using trap plants of common chickweed (Stellaria media) at 2, 6 and 12 m from the tomatoes within each vegetation management plot. Chickweed plants were sampled in the autumn and spring from 2004 to 2006. Sticky traps were placed next to trap plants in the autumn of 2005 to monitor aerial dispersal of mites. Mite populations infesting chickweed were low, and autumn dispersal of mites from tomatoes to the chickweed plots was considered to be short range. The vegetation management strategies had no effect on mite densities found in the chickweed, but the capture of mites on sticky traps indicated that aerial dispersal was also a means of dispersal to overwintering hosts. [source]

    Influence of water extracts from the surface of two Yew (Taxus) species on mites (Tetranychus urticae)

    Miroslawa Furmanowa
    Abstract Taxus cuspidata and Taxus media var. Hicksii contain paclitaxel, among other taxoids, on the surface of the needles. These compounds were removed by 5-s dipping of the needles in water just below its boiling point at 96C and at 60C and 40C. Taxus cuspidata contained a fourfold higher concentration of paclitaxel than Taxus media var. Hicksii. The extract with the higher concentration of paclitaxel was more harmful to the mites Tetranychus urticae Koch, increasing their mortality 150%, prolonging development by ca. 20% and lowering the average fecundity from 112 in the control to 16.13 after treatment with Taxus cuspidata; also, the net reproductive rate dropped from 70.24 to 6.70, which is more than a tenfold reduction. Copyright 2002 John Wiley & Sons, Ltd. [source]

    In vitro effects of flutriafol and azoxystrobin on Beauvaria bassiana and its efficacy against Tetranychus urticae

    Mutimura C Gatarayiha
    Abstract BACKGROUND: Testing the compatibility of chemical pesticides and fungal biocontrol agents is necessary if these two agents are to be applied together in the integrated management of plant pests and diseases. In this study, the fungicides azoxystrobin (a strobilurin) and flutriafol (a triazole) were tested in vitro for their effects on germination of conidia and mycelial growth of Beauveria bassiana (Bals.) Vuill. and in bioassay for their effect on fungal activity against Tetranychus urticae Koch. The fungicides were tested at three different concentrations [recommended rate for field use (1 X) and the dilutions 10,1 X and 10,2 X]. RESULTS: Flutriafol inhibited growth of mycelia and germination of the fungal conidia at all concentrations tested in vitro, and also reduced the efficacy of B. bassiana in bioassays against mites. The inhibitive effect of azoxystrobin in vitro varied with the concentration applied. A significant effect was observed at 1 X and 10,1 X concentrations on both the germination of conidia and mycelia growth. At 10,2 X concentration, azoxystrobin showed little effect on B. bassiana. However, when this fungicide was tested in bioassays, none of the concentrations reduced B. bassiana activity against mites. CONCLUSION: Azoxystrobin was most compatible with B. bassiana, while flutriafol was the most harmful. Further studies are required to confirm the negative effect of flutriafol on B. bassiana activity. Copyright 2010 Society of Chemical Industry [source]

    The discovery of HNPC-A3066: a novel strobilurin acaricide

    Aiping Liu
    Abstract BACKGROUND: Although more than ten strobilurin analogues have been commercialized since 1996 as fungicides, only one was available as an acaricide as of 2003. To search for novel strobilurin analogues with unique biological activities, a synthetic screening programme was carried out. RESULTS: Syntheses of compounds analogous to the commercialized fungicide metominostrobin and the acaricide fluacrypyrim led to the discovery of a lead compound, (E)-2-{2-[[3,5-bis(trifluoromethyl)phenoxy]methyl]phenyl}-2-(methoxyimino)- N -methylacetamide (3b), that showed moderate acaricidal activity against Tetranychus urticae Koch. Compound 3b has a 3,5-(CF3)2 -phenoxymethyl group instead of the unsubstituted phenoxy substituent in metominostrobin. Optimization of compound 3b was achieved by introducing an oxime ether bridge along with an alkylthio(alkyl) branch in place of the oxymethylene chain between two aromatic moieties, as well as by replacing the methoxyiminoacetamide group with a methoxyacrylate structure, leading to (E)- methyl 2-{2-[[[(Z)[1-(3,5-bis(trifluoromethyl)phenyl)-2-methylthioethylidene]amino]oxy] methyl]phenyl}-3-methoxyacrylate (6c) and (E)- methyl 2-{2-[[[(Z)[1-(3,5-bis(trifluoromethyl)phenyl)-1-methylthiomethylidene]amino]oxy]methyl]phenyl}-3-methoxyacrylate (9a, HNPC-A3066). CONCLUSION: The above two compounds (6c, 9a) were shown to exhibit potent acaricidal and fungicidal activity. Compound 9a (HNPC-A3066) also exhibits larvicidal and ovicidal activities against various acarids. The acaricidal potency is comparable with those of commercial acaricides such as fluacrypyrim, tebufenpyrad and chlorfenapyr. Copyright 2008 Society of Chemical Industry [source]

    Impact of intraguild predation and lambda-cyhalothrin on predation efficacy of three acarophagous predators

    Caroline Provost
    Abstract This laboratory study reports the interaction of three predators found in commercial apple orchards in Quebec, Hyaliodes vitripennis (Say) (Hemiptera: Miridae), Harmonia axyridis Pallas (Coleoptera: Coccinellidae) and Amblyseius fallacis (Garman) (Acarina: Phytoseiidae). First, intraguild predation between H vitripennis and the two other predators was characterized in the absence and presence of their extraguild prey, Tetranychus urticae Koch. The results showed an asymmetrical interaction in favour of the larger predator and the levels of intraguild predation were weak for the two predatory combinations. Presence of the phytophagous mite reduced the intensity of intraguild predation in the predatory combination of H axyridis and H vitripennis. Second, the effects of intraguild predation and the application of lambda-cyhalothrin on predation efficacy of the predators were evaluated. The application of the insecticide reduced prey consumption of H vitripennis and H axyridis but did not affect that of A fallacis. Combination of predators and an insecticide application resulted in two different situations depending on the species involved: a reduced predation efficacy for the combination of H vitripennis and H axyridis due to a knockdown effect caused by the insecticide, and no effect on T urticae consumption for H vitripennis and A fallacis. It is suggested that an integrated pest management program based on H vitripennis, A fallacis and lambda-cyhalothrin may be evaluated to repress phytophagous mites in Quebec orchards. Copyright 2005 Society of Chemical Industry [source]

    Relative toxicity of nC24 agricultural mineral oil to Tetranychus urticae Koch (Acari: Tetranychidae) and Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) and its possible relationship to egg ultrastructure

    Yingen Xue
    Abstract The relative toxicity (LC50 values based on g oil/cm2) is evaluated of aqueous nC24 agricultural mineral oil (AMO) emulsions to the egg, six-legged nymph (larva), eight-legged protonymph and adult stages of two-spotted mite (Tetranychus urticae) and its predator, Phytoseiulus persimilis, on French bean leaf discs, using a Potter spray tower to apply of the oil. The egg of P. persimilis was the least susceptible stage (LC50 444.84) and its LC50 was significantly higher than all other stages tested of either P. persimilis or T. urticae. The LC50 for adult female T. urticae (LC50 63.89) was significantly lower than the larva (LC50 93.86); however, there was no significant difference in response between the protonymph (LC50 70.44) and the larva, which were both higher than T. urticae eggs (LC50 17.55). LC50s for P. persimilis larva (LC50 43.87), protonymph (LC50 41.55) and adult female (LC50 53.34) were similar. Scanning electron microscopy showed that the egg surface of T. urticae is usually well covered with fine silk that may trap more oil and increase AMO efficacy. Other possible differences in AMO efficacy between T. urticae and P. persimilis may be due to differences in egg size, egg incubation period, egg surface structure and the presence of vulnerable respiratory cones in T. urticae eggs. Dose of 0.2,0.3% (w/w) is considered to be the most appropriate for nC24 AMOs use against T. urticae in combination with P. persimilis in integrated pest management programs. [source]

    Impact of nC24 agricultural mineral oil deposits on the searching efficiency and predation rate of the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae)

    Yingen Xue
    Abstract Walking activity, walking straightness, walking speed and searching efficiency of the predatory mite Phytoseiulus persimilis Athias-Henriot were measured on French bean leaf discs that were sprayed with either distilled water, or one of 0.25%, 0.50% and 1.00% w/w aqueous emulsions of an nC24 agricultural mineral oil (AMO). There was no significant difference in percentage of time that mites spent walking in the control (water-sprayed) conditions and in any of the oil treatments. Walking paths were significantly straighter in the oil treatments than in the control, but differences among the oil treatments did not differ significantly. Walking speeds in the oil treatments were significantly slower than in the control and decreased with increasing oil concentration. Deposits of oil at all concentrations significantly suppressed searching efficiency in comparison with control, and searching efficiency in the 1.00% oil treatment was significantly lower than in the 0.25% oil treatment. First predation of P. persimilis on AMO-contaminated eggs of two-spotted mite (Tetranychus urticae Koch) on unsprayed leaf discs was significantly delayed in all oil treatments in comparison with the control. However there was no significant effect on the overall predation rate. In the tests of P. persimilis predation on AMO-contaminated T. urticae eggs on sprayed leaf discs, the number of first predation occurrences in the first hour was significantly lower in 0.50% and 1.00% oil treatments than in the control. Overall predation rates were significantly reduced by oil but they did not differ significantly among the oil treatments. [source]