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121.
122.
A trial was carried out to investigate the efficacy of methacrifos against susceptible and multi-resistant strains of four species of insect and three species of mite. Methacrifos was applied to two separate 20-tonne loads of English wheat which were then stored under ambient conditions for 24 weeks. The efficacy of methacrifos was assessed using established bioassay techniques which showed complete control for 24 weeks of all susceptible insects except S. oryzae, where there were survivors at week 24. Methacrifos also gave 100% mortality of resistant O. surinamensis for 24 weeks. There was >95% mortality for 16 weeks of resistant strains of T. castaneum and of resistant S. granarius and S. oryzae for 20 weeks. After S. granarius and S. oryzae were removed, the grain was incubated for 10 weeks. Subsequent F1 emergence was considerably less from the treatments than from the controls. Methacrifos produced 100% mortality for T. longior for 24 weeks, but control of G. destructor fluctuated and was <100% at week 24. There were survivors of A. siro from week 4. 相似文献
123.
David H. L. Bishop 《Pest management science》1989,27(2):173-189
Among the viruses that are pathogenic for insect species, baculoviruses have been shown to be useful as insecticides for pest control. In some cases they have been used as cost-effective and environmentally acceptable alternatives to chemical insecticides. However, because viruses need to be ingested and replicate extensively in their host before they kill it, baculovirus insecticides are much slower than chemicals or other reagents that kill insects either on contact or shortly after ingestion. The objective of the programme of genetic engineering of baculovirus insecticides is to improve their speed of action while maintaining their host specificity and other attributes that make them desirable alternatives to chemical pesticides. Since 1986 four field releases have been undertaken involving genetically engineered baculovirus insecticides. The first release used a genetically marked Autographa californica nuclear polyhedrosis virus (AcNPV). The study began in 1986 and was terminated in 1987. The results demonstrated that an innocuous piece of DNA, appropriately positioned in the AcNPV genome, was an effective means to tag the virus without affecting its phenotype, allowing it to be identified in bioassays of plant and soil samples. The second release, in 1987, involved a genetically marked virus from which the gene coding for the protective polyhedrin protein of the virus had been removed. The field data obtained with this virus showed that it did not persist in the environment, neither in soil, nor on vegetation, nor in the corpses of caterpillars. The third and fourth releases were undertaken in 1988. For one of these studies the marked, polyhedrin-negative virus was again used. In the other study a polyhedrin-negative virus that contained a junk' (/?-galactosidase) gene was employed. 相似文献
124.
David C. Griffiths John A. Pickett Lesley E. Smart Christine M. Woodcock 《Pest management science》1989,27(3):269-276
The probing and feeding behaviour of aphids can result in uptake of viruses from infected plants and subsequent transmission to healthy plants. It is possible to interfere with virus acquisition and transmission by influencing aphid host-selection and feeding behaviour with antifeedant chemicals. Published work is reviewed and new work is presented in this paper. The two most successful classes of antifeedants against aphids are (a) compounds derived from the aphid alarm pheromone and (b) plant-derived antifeedants such as the sesquiterpene (-)-polygodial. Results with these and other compounds are discussed in terms of antifeedant activity against Myzus persicae, their effects on resistant aphids and the evidence for dec?ease in virus spread by aphids in laboratory and field. 相似文献
125.
126.
The eukaryotic cell membrane is thought to consist of a mobile bilayer of phospholipid, sometimes intercalated with sterols, in which peripheral and transmembrane proteins are embedded. This provides a model whereby the mode of action of many fungicidal and herbicidal compounds can be rationalised and understood. Some compounds, such as the polyene antibiotics, steroidal saponins and certain phytoalexins, induce membrane malfunction by direct insertion, often complexing with vital components. Others, such as paraquat and the nitrodiphenyl ether herbicides, cause membrane damage by inducing lipid peroxidations. Furthermore, there are many compounds, including the sterol-biosynthesis-inhibiting fungicides and the aryloxyphenoxypropionate and cyclohexanedione herbicides, which interfere with the biosynthesis of membrane components. Because membrane structure is fundamentally similar in eukaryotes, it is important to discover the reasons for any differential toxicity displayed by these compounds and, if necessary, to find ways of optimising desirable patterns of selectivity. 相似文献
127.
The effect of acifluorfen and oxyfluorfen on chlorophyll bleaching, lipid peroxidation and photosynthesis in pea leaf discs was studied. Both her- bicides induced light-dependent bleaching and lipid peroxidation, the level of damage being greater at higher light intensities. Photosynthetic carbon dioxide fixation was only partially inhibited in treated leaf discs incubated in darkness, thus indicating that these herbicides did not inhibit photo- synthesis as a primary mode of action. Leaf discs maintained in darkness showed no visible signs of injury, and light-dependent herbicide-induced damage was reduced by incubating discs under nitrogen, orpre-incubating them with the electron-transport inhibitor monuron. It is suggested that acifluorfen and oxyfluorfen are activated by a light-dependent process, which requires photosynthetic electron transport. 相似文献
128.
The effects of permethrin on native and caged fish when aerially applied directly to forest streams at dosages between 8.8 and 70 g ha?1 were studied between 1976 and 1981. None of the applications caused mortality of caged or native fish in streams. Trout and salmon diets were altered by the treatments due to effects on fish food organisms. The duration of the effects varied from several months to over a year with increasing dosage. Reductions in salmonid growth rates and reductions in fish densities in treated areas, presumably due to emigration, were documented following severe impacts on aquatic invertebrates in salmon nursery streams. Growth rates and population densities both recovered within four months after treatment. 相似文献
129.
A series of experiments was conducted between 1977 and 1981 to evaluate the effects of aerially applied permethrin on forest stream invertebrates. All permethrin applications to forest streams resulted in large drift increases, and most produced measurable reductions in benthos density. Recovery of benthic fauna following the various permethrin applications was apparent from 1 to 18 months post-spray. In double-application experiments, the second treatments reduced benthos density to a point at which recovery of numbers was slower than after the impact resulting from a single application of the same dosage. 相似文献
130.
Geoffrey G. Briggs George R. Cayley Glenn W. Dawson David C. Griffiths Ewen D. M. Macaulay John A. Pickett Mary M. Pile Lester J. Wadhams Christine M. Woodcock 《Pest management science》1986,17(4):441-448
Two analogues of the aphid alarm pheromone (E)-β-farnesene, a trifluorofarnesene and a difluoro-1-norfarnesene, were found to be highly active and were more readily detectable than the parent compound. For (Z)-hexadec-11-enal, a component of some lepidopteran sex attractant pheromones, replacement of the carbonyl oxygen with a difluoromethyl group to give a difluoroheptadecadiene resulted in loss of activity. A trifluoroacetoxyhexadecanolide was a more volatile analogue of the mosquito oviposition pheromone (?)-(5R,6S)-6-acetoxy-5-hexadecanolide and was highly active. 相似文献