Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pest Control, Biological”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMedDate not supplied

Morphological mutant in the entomopathogenic nematode, Heterorhabditis bacteriophora.

Heterorhabditis bacteriophora is an entomopathogenic nematode that has potential as a biological control agent. As a first step in the genetic analysis of this nematode, we induced and isolated a short nematode (dumpy) from the F2 progeny of an EMS mutagenized nematode. Phenotypically, the dumpy adult is 60% shorter than the wild type. There is almost no longitudinal growth after the infective juvenile stage. Dumpy is completely recessive with 100% penetrance and uniform expressivity. When F1 progeny were allowed to self, F2 progeny segregated wild: dumpy in a 15:1 ratio (chi 2 = 0.634, .5 > P > .2). This dumpy mutation (Rhdpy) complements another dumpy mutation isolated in Israel and is the second gene known for this species.

Animals↗
PubMed1995

Molecular genetic manipulation of mosquito vectors.

Despite their central role in disease transmission, relatively little is known of the molecular biology of arthropod vectors. Modern molecular approaches will undoubtedly provide considerable information about gene regulation and expression in vectors and consequently a much better understanding of the biology and molecular biology of vectors. Such knowledge is essential for developing effective control strategies for vector-borne diseases. In this review, we focus upon techniques and approaches used at the Arthropod-Borne and Infectious Diseases Laboratory (AIDL) at Colorado State University to bioengineer mosquitoes with reduced vector competence. We have developed technologies and procedures that allow genetic manipulation of mosquitoes, including RNA and DNA virus gene-delivery vehicles and efficacious antiviral constructs, which will facilitate the development of pathogen-resistant, transformed mosquitoes. Many of the approaches, constructs, and technologies developed at AIDL will be applicable to molecular manipulation of other arthropod genomes.

Animals↗
PubMedDate not supplied

[Conceptual basis for defining viral insecticide harmlessness for human health and the environment].

The qualitative distinction of the new class of virus-based biopesticides from chemicals is the intracellular parasitism of the active agent in the organisms of the living biological host, its capacity to join natural microbiocenoses and to restrain the number of the destructive species over a long period of time. Thus, the program of the study of harmlessness of entomopathogenic viruses must be aimed at preventing the possibility of their adaptation to non-target animals, reproduction and the ability to provoke the non-specific infection. Other parameters such as toxicity and allergenicity of the preparations and their standardization will be investigated under the absence of such ability. The appropriate schemes and methods of investigations have been developed.

Baculoviridae↗
PubMed2001

Biological control of strawberry tarsonemid mite Phytonemus pallidus and two-spotted spider mite Tetranychus urticae on strawberry in the UK using species of Neoseiulus (Amblyseius) (Acari: Phytoseiidae).

Two species of Neoseiulus, N. californicus and N. cucumeris, showed potential for biocontrol of phytophagous mites on strawberry. N. californicus controlled Tetranychus urticae on potted strawberry plants in a gauze-sided glasshouse at temperatures comparable to early summer in the UK (8-20 degrees C). Both species of phytoseiid reduced numbers of the tarsonemid Phytonemus pallidus on potted strawberry plants under glasshouse conditions (15-23 degrees C). In several experiments reductions in the range of 71-81% in numbers of tarsonemid active stages and eggs, compared to non-release plants, were obtained. The importance of establishing a suitable predator: prey ratio at an early stage was demonstrated in an experiment where an initial ratio of 1 N. cucumeris: 10 P. pallidus gave a greater degree of control than 1:20 or 1:40.

Animals↗
PubMed2004

Allozyme markers to help define the South American origins of Microctonus hyperodae (Hymenoptera: Braconidae) established in New Zealand for biological control of Argentine stem weevil.

The thelytokous parasitoid, Microctonus hyperodae Loan, was collected from eight South American locations and introduced to New Zealand in 1991 for biological control of Argentine stem weevil, Listronotus bonariensis (Kuschel) (Coleoptera: Curculionidae). Parasitoids from each population were released in equal numbers at each New Zealand site to give them the same opportunities to establish. Population markers have been sought to identify the South American geographic populations that have become most successful in New Zealand. These would assist in determining the importance of concepts such as climate matching and host-parasitoid coevolution to the establishment of natural enemies in new regions for biological control. Vertical polyacrylamide electrophoresis was used to survey 16 enzymes and ten calcium binding proteins, and this paper reports variation at three putative loci. Malate dehydrogenase, a dihydrolipoamide dehydrogenase isozyme and a calcium binding protein exhibited clear genetic variation, each with two alleles. All M. hyperodae isofemale lines from east of the Andes mountains shared one genotype, all but one from west of the Andes shared another, while a population from within the Andes contained both genotypes. This variation was highly congruent with previously described morphometric variation. At two loci, the maintenance of heterozygotes, and the absence of homozygotes, within isofemale lines suggested M. hyperodae thelytoky is apomictic.

Animals↗
PubMed1973

Prospects for biological control of rodent populations.

Pathogens and predatory animals are the main agents used for the biological control of rodents. The pathogens that have been used are of the genus Salmonella; none is rodent-specific and all can cause severe infection in man and domestic animals. Furthermore, rodents frequently develop immunity to, and become carriers of, these organisms, and there is little to commend their use, except in lightly populated areas where control is infrequently applied. The relationships of five predator species with their rodent prey have been examined. The monitor lizard, mongoose, and ferret were for different reasons found to be unsatisfactory, and there is not yet sufficient evidence to warrant further releases of the Japanese weasel. Domestic and feral cats control rodents well in some situations but only after some other agent has removed a large part of the rodent population.

Animals↗
PubMed2001

Distinctive hydrocarbons of the black dump fly, Hydrotaea aenescens (Diptera: Muscidae).

Hydrotaea aenescens (Wiedemann), the black dump fly, is a potential biological control agent originally from the western hemisphere, now found in many parts of the Palearctic region except for the United Kingdom, where it cannot be imported for any reason. A complication of classical biological control is the problem of strain identification, as one must be able to somehow mark or follow a particular strain that has been introduced into the field or is contemplated for release. Gas chromatographic analysis of the surface hydrocarbons of pooled and individual dump fly adults resulted in reproducible hydrocarbon patterns that differentiated widely distributed strains of H. aenescens and showed similarities between strains that were related. Sexual dimorphism was observed in the surface hydrocarbons. Conspecific similarities included identities of the hydrocarbons found in colony material collected worldwide, with differences being found in the quantities of compounds present.

Age Factors↗
PubMed1995

Malaria: current and future prospects for control.

Malaria is the most important insect-transmitted human disease, but progress in its control has been slow, especially in Africa where approximately 90% of the infections occur. Several factors have contributed to the problem. Parasites and vectors have developed resistance to antimalarial drugs and insecticides; differences in the biology of major malaria vectors preclude the development of simple, universally applicable strategies for malaria control; and the cost of available malaria-control tools often exceeds the public health resources in the most malarious parts of the world. New tools are desperately needed. Current efforts include the testing of tools such as insecticide-impregnated bed nets that could become available in the near term, as well as long-term projects such as the development of malaria vaccines and mosquito-targeted genetic control strategies. The success or failure of any of these approaches will depend ultimately on understanding the natural patterns of malaria transmission in the field.

Animals↗
PubMed1976

Application of Bathurin and borax in the biological control of Monomorium pharaonis in housing estates.

Of two apartment houses infested with ants of the species Monomorium pharaonis, one was treated with a biological, the other with a chemical substance. In the first case we used Bathurin in combination with borax at a concentration of 1.3% for both substances. In the first week, borax was added to the bait (minced beef), within the next three weeks, the bait was mixed with Bathurin. The procedure was repeated 5 times. After this period, we achieved complete control of the ants on the infested premises.--Our results obtained with the chemical substance (the insecticide Anthrix) were less successful. This indicates that the first method, although time-consuming and requiring a perfect collaboration with all inhabitants, is safer, because it leads to the complete eradication of ants in the infested premises.

Animals↗
PubMed2007

Expressed sequence tags-based identification of genes in the biocontrol agent Chaetomium cupreum.

Chaetomium cupreum has a potential as biocontrol agent against a range of plant pathogens on the basis of production of antifungal metabolites, mycoparasitism, competition for space and nutrients, or various combinations of these. To explore genes expressed in C. cupreum, a cDNA library was constructed from mycelium and 3,066 expressed sequence tags (ESTs) were generated. Clusters analysis enabled the identification of 1,471 unigenes with 392 contigs and 1,079 singleton sequences. Putative functions were assigned to 874 unigenes that exhibited strong similarity to genes/ESTs in public databases putatively containing genes involved in cellular component, molecular function, and biological process. Other 597 ESTs representing novel genes showed no significant similarity to public database resource of NCBI. A proportion of genes was identified related to degradation of pathogen cell wall, antifungal metabolite production, as was estimated in the biocontrol fungus. The paper described is a first step towards the knowledge of the C. cupreum genome. The results present the useful application of EST analysis on C. cupreum and provide a preliminary indication of gene expression putatively involved in biocontrol.

Chaetomium↗
PubMed2001

Invading freshwater snails and biological control in Martinique Island, French West Indies.

Eight alien freshwater snail species were introduced into Martinique Island during the last 50 years. The introduced snails include four planorbids (Biomphalaria straminea, Helisoma duryi, Amerianna carinata and Gyraulus sp.), three thiarids (Melanoides tuberculata, M. amabilis and Tarebia granifera) and one ampullarid (Marisa cornuarietis). Four of these species rapidly colonized the whole Martinican hydrographic system whereas the other four remained restricted to some particular sites. The invasion processes were documented during the last 20 years and showed (i) a rapid invasion of the island by several morphs of M. tuberculata at the beginning of the 80's; (ii) the introduction of T. granifera in 1991 and M. amabilis in 1997; and (iii) the rapid spread of these last two species throughout the island. In the years following its introduction, M. tuberculata was used in biological control experiments against the snail hosts of schistosomiasis, B. glabrata and B. straminea. Experiments were conducted with success in several groups of water-cress beds which constituted the latest transmission sites for schistosomiasis at the beginning of the 80's. A malacological survey carried out in 2000 all over the island showed the absence of B. glabrata but the presence of some residual populations of B. straminea. Long-term studies carried out in Martinique have shown that the thiarids are able to maintain relatively stable populations over a long period of time, thus preventing recolonization by the snail hosts. Within this context the invasion of the hydrographic system of Martinique by thiarid snails has resulted in an efficient and sustainable control of the intermediate hosts of schistosomiasis.

Animals↗
PubMed2005

Biological protection of the main cereals against fungal specific diseases.

Our field experiments showed that the use of Czech biopreparations (Supresivit, Ibefungin and Polyversum) based on the following microorganisms: Trichoderma harzianum, Bacillus subtilts and Pythium oligandrum applied as the seed treatment, the spray on the plants and like the mixture with mineral fertilizers (NPK, ammonium sulphate) lead namely after the seed-treatment and after the application as the mixture with mineral fertilizers to the increasing of the yield about 3-5 % (spring barley, winter wheat). This increasing was given by depression of soil-borne phytopathogenic fungi of the genera: Fusarium, Drechslera (Helminthosporium), Pseudocercosporella (Tapesia), Gaeumannomyces, and partially Rhynchosporium. The number of the fungi on plant rests were also influenced. No effect was observed on smuts and rusts. The smuts needed the seed-treatment with Vitavax (carboxim, thiram, imazalil) which didn't influence the biological treatment with biopreparations. The doses of biopreparations were following: the mixture with mineral fertilizer - 0.1 g of biopreparation/ kg of mineral fertilizer, the seed treatment - 0.1 g of biopreparation/1 kg of the seed and in the spray 0.1 g of biopreparation/1 litre of distilled water. Biological biopreparations will be usefull probably also in the future because they don't create the harmfull residues. The impact of the biopreparations under different ways of soil tillage (conventional variant with ploughing, variants with different plant residues and variants without ploughing) was studied as well. The influence of different soil preparation on composition of the soil mycoflora and the influence on quantity of the pathogenic genera Fusarium, Drechslera and others was observed. Quantity of named genera was negatively influenced while yield and health status of the plants were influenced positively.

Agriculture↗
PubMed1990

Methods currently used for the control of one-host ticks: their validity and proposals for future control strategies.

Available methods for the control of one-host ticks as well as their possible applications in control programmes are reviewed. The advantages and disadvantages of current methods (dipping vats, spray races, hand sprays) are compared to other chemical control methods (ear-tags, pour-ons, systemics, slow-release devices). Their integrated application with other technologies based on immunological, genetic or biological approaches is discussed. Because of the great diversity of geographic, climatic, infrastructural and scientific-technological developments in vast areas of the world, the author concludes that there is no universal method of application. What really matters is to be able to develop control programmes based on local ecological, socio-economic and political facts, integrating the best of available technology. Future tick control prospects are discussed with reference to the need for standardization of criteria on requirements and the legal basis for acaricide registration, introduction of new evaluation techniques for acaricide efficacy and development of faster techniques to recognize resistance. Special emphasis is laid on the need to establish control programmes integrating diagnosis, research and production of vaccines against one-host ticks and their haemoparasites.

Animals↗
PubMedDate not supplied

[Control of vectors of human onchocerciasis in intertropical Africa (author's transl)].

First the authors make short comments on the two Simuliidae species complexes vectors of African human onchocerciasis (S. damnosum s.l. and S. neavei), as well as on the reasons for renewed interest in the control of those vectors; then they review the various possible methods of control (ecological, biological, genetical and chemical methods) and they finally detail the methodology of anti-S. damnosum chemical larviciding which is the only kind or large scale control presently used against onchocerciasis vectors. The experiences and results of the previous campaigns resulted in the large Onchocerciasis Control Programme in Volta River Basin (O.C.P.) which now appears as a model for present and future control measures against S. damnosum. This Programme is briefly described, together with its results, problems (reinvasion) and orientations. As a conclusion, the excellent level of control of the vectors and onchocerciasis transmission which is obtained is emphasized and it is expected that in the future new large scale campaigns using O.C.P. experience may be initiated.

Africa↗
PubMed1997

Evaluation of Caribbean strains of Macrocyclops and Mesocyclops (Cyclopoida:Cyclopidae) as biological control tools for the dengue vector Aedes aegypti.

Fifteen Caribbean strains of copepods were assessed for their predation ability against mosquito larvae. Macrocyclops albidus from Nariva. Mesocyclops aspericornis from Oropouche, and Mesocyclops longisetus from E1 Socorro, Trinidad, were most effective against Aedes aegypti but not against Culex quinquefasciatus. Mesocyclops longisetus and Me. aspericornis prevented any mosquito survival over 25 wk of observation despite weekly challenges with Ae. aegypti. The copepods were tolerant to dosages of the insecticide temephos that are usually toxic to mosquito larvae. This indicated that copepods could be incorporated into an integrated control system. To determine whether pathogenic microbes might be introduced with copepods into drinking water, microbial studies were done on the copepods. These showed the presence of only Aeromonas sobria, Pseudomonas sp., Alcalignes sp., and gram-positive bacilli. Although none of these are highly pathogenic to humans, the application of these copepods has not yet been recommended for use in drinking water.

Aedes↗
PubMed2006

Insect antifeedants, pterocarpans and pterocarpol, in heartwood of Pterocarpus macrocarpus Kruz.

The insect antifeedant activities of pterocarpans and a sesquiterpene alcohol from the dichloromethane extract of Pterocarpus macrocarpus Kruz. (Leguminosae) were evaluated against the common cutworm, Spodoptera litura F. (Noctuidae), and the subterranean termite, Reticulitermes speratus (Kolbe)(Rhinotermitidae). Three pterocarpans, (-)-homopterocarpin (1), (-)-pterocarpin (2), and (-)-hydroxyhomopterocarpin (3) and the sesquiterpene alcohol, (+)-pterocarpol (5), were isolated from the dichloromethane extract of the heartwood of P. macrocarpus under guidance by a biological assay. Among these natural products, the most active insect antifeedant against both S. litura and R. speratus was 1. On the other hand, sesquiterpene alcohol 5 showed less insect antifeedant activity than the other pterocarpans against both insect species. While its methylated derivative, (-)-methoxyhomopterocarpin (4), showed high biological activity, 3 showed less insect antifeedant activity in this study. Interestingly, racemic 1 did not show insect antifeedant activity against S. litura. However, all of the test pterocarpans and isoflavones showed antifeedant activity against the test termites. Additionally, since these compounds were major constituents of P. macrocarpus, these antifeedant phenolics may act as chemical defense factors in this tree. In Thailand, lumber made from this tree is used to make furniture and in building construction due to its resistance to termite attack.

Alcohols↗
PubMed2006

Quorum-sensing system influences root colonization and biological control ability in Pseudomonas fluorescens 2P24.

Pseudomonas fluorescens 2P24 is a biocontrol agent isolated from a wheat take-all decline soil in China. This strain produces several antifungal compounds, such as 2,4-diacetylphloroglucinol (2,4-DAPG), hydrogen cyanide and siderophore(s). Our recent work revealed that strain 2P24 employs a quorum-sensing system to regulate its biocontrol activity. In this study, we identified a quorum-sensing system consisting of PcoR and PcoI of the LuxR-LuxI family from strain 2P24. Deletion of pcoI from 2P24 abolishes the production of the quorum-sensing signals, but does not detectably affect the production of antifungal metabolites. However, the mutant is significantly defective in biofilm formation, colonization on wheat rhizosphere and biocontrol ability against wheat take-all, whilst complementation of pcoI restores the biocontrol activity to the wild-type level. Our data indicate that quorum sensing is involved in regulation of biocontrol activity in P. fluorescens 2P24.

4-Butyrolactone↗
PubMed1992

Expression of the mosquitocidal toxins of Bacillus sphaericus and Bacillus thuringiensis subsp. israelensis by recombinant Caulobacter crescentus, a vehicle for biological control of aquatic insect larvae.

In the quest for effective control of mosquitoes, attention has turned increasingly to strains of the bacteria Bacillus sphaericus and Bacillus thuringiensis subsp. israelensis, which produce potent toxins with specific mosquitocidal activities. However, sedimentation of the bacterial spores limits the duration of effective control after field application of these bacilli. We describe here the cloning of genes encoding the 51.4- and 41.9-kDa toxins from B. sphaericus 2297, the 100-kDa toxin from B. sphaericus SSII-1, and the 130-kDa toxin from B. thuringiensis subsp. israelensis into the broad-host-range plasmid pRK248 and the transfer of these genes for expression in Caulobacter crescentus CB15. The recombinant C. crescentus cells were shown to be toxic to mosquito larvae. Caulobacter species are ubiquitous microorganisms residing in the upper regions of aquatic environments and therefore provide the potential for prolonged control by maintaining mosquitocidal toxins in larval feeding zones.

Animals↗