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At least 613 records · Page 34Linked to original sources
PubMed2005

Toxicity of commonly used insecticides in sweet corn and soybean to multicolored Asian lady beetle (Coleoptera: Coccinellidae).

Use of insecticides with low toxicity to natural enemies is an important component of conservation biological control. In this study, we evaluated the toxicity of insecticides used in sweet corn, Zea mays L., and soybean, Glycine max (L.) Merr., to the multicolored Asian lady beetle, Harmonia axyridis (Pallas), under laboratory and field conditions. Field experiments conducted in sweet corn in 2003 and 2004 and in soybean in 2003, showed that H. axyridis was the most abundant predator. In sweet corn, densities of H. axyridis larvae in plots treated with spinosad or indoxacarb were generally higher than in plots treated with chlorpyrifos, carbaryl, bifenthrin, and A-cyhalothrin. In soybean, densities of H. axyridis larvae in plots treated with chlorpyrifos were higher than in plots treated with lambda-cyhalothrin. Laboratory experiments were conducted to evaluate the acute toxicity of insecticides to eggs, first and third instars, pupae, and adults. Spinosad, followed by indoxacarb, were the least toxic insecticides for all life stages of H. axyridis. Conventional insecticides showed high toxicity to H. axyridis when applied at field rates under laboratory conditions. Overall, first instars were most susceptible to the insecticides tested, followed by third instars and adults, eggs, and pupae. Our results suggest that spinosad, and to a lesser extent indoxacarb, offer reduced toxicity to H. axyridis and would be beneficial for conservation biological control in agricultural systems where H. axyridis is abundant.

Animals↗
PubMed2003

Effects of Plagiorchis elegans (Digenea: Plagiorchiidae) infection of Biomphalaria glabrata (Pulmonata: Planorbidae) on a challenge infection with Schistosoma mansoni (Digenea: Schistosomatidae).

Prior exposure of Biomphalaria glabrata to the eggs of an incompatible digenean, Plagiorchis elegans, rendered this snail host less suitable to a compatible species, Schistosoma mansoni. Although P. elegans failed to develop patent infections in B. glabrata, it reduced the production of S. mansoni cercariae by 88%. Concomitantly, host attributes such as reproduction, growth, and survival were compromised. The effect of P. elegans infection was most severe among snails that, in addition, had developed patent schistosome infections. Although few S. mansoni cercariae were produced, egg production by B. glabrata was only 4% of control values. Furthermore, no doubly infected snails survived for more than 3 wk after patency, whereas controls experienced no mortality during the same time period. The above effects were attributable to the establishment and persistence of P. elegans sporocysts in the tissues of the incompatible snail host. Their indirect antagonistic interaction with thelarval stages of S. mansoni may be mediated, in part, through their long-term stimulation of the host's internal defense mechanisms. These findings are discussed with a view to use P. elegans and other plagiorchiid digeneans as agents in the biological control of snails and snail-borne diseases.

Animals↗
PubMed1979

The influence of temperature, darkness, and starvation on growth and survival of Helisoma duryi, Biomphalaria alexandrina and Bulinus truncatus.

The influence of 10 degrees, 18 degrees, 26 degrees, 28 degrees and 33 degrees C, different periods of complete darkness and starvation on growth and survival of H. duryi, B. alexandrina and B. truncatus were studied. The optimum temperature for the growth and survival was about 26 degrees C. Survivorship and growth rates decreased proportionately according to starvation period. However, darkness had no significant effect on the growth of B. truncatus and H. duryi. Under the chosen experimental conditions H. duryi revealed higher tolerance limits and survival rates than B. alexandrina and B. truncatus. The potential of H. duryi as biological control agent of Schistosome vector snails is discussed.

Animals↗
PubMed2003

Galls on thistles.

Plant galls - the more we learn, the more there is to know! Approximately 15000 insect species ( c. 2% of all known insects) form galls, and this habit is extremely common over a range of floras and latitudes. Yet, there is still no general consensus on why they exist. Thistle-galling insects are relatively well known and are used as biological control agents (of thistles) and model ecological systems.

Animals↗
PubMed2005

Integrated management of root-knot nematode, Meloidogyne incognita infestation in tomato and grapevine.

An integrated approach with the obligate bacterial parasite, Pasteuria penetrans and nematicides was assessed for the management of the root-knot nematode, Meloidogyne incognita infestation in tomato and grapevine. Seedlings of tomato cv. Co3 were transplanted into pots filled with sterilized soil and inoculated with nematodes (5000 juveniles/pot). The root powder of P. penetrans at 10 mg/pot was applied alone and in combination with carbofuran at 6 mg/pot. Application of P. penetrans along with carbofuran recorded lowest nematode infestation (107 nematodes/200 g soil) compared to control (325 nematodes/200 g soil). The rate of parasitization was 83.1% in the carbofuran and P. penetrans combination treatment as against 61.0% in the P. penetrans treatment only. The plant growth was also higher in the combination treatment compared to all other treatments. A field trial was carried out to assess the efficacy of P. penetrans and nematicides viz., carbofuran and phorate in the management of root-knot nematode, M. incognita infestation of grapevine cv. Muscat Hamburg. A nematode and P. penetrans infested grapevine field was selected and treatments either with carbofuran or phorate at 1 g a.i/vine was given. The observations were recorded at monthly interval. The results showed that the soil nematode population was reduced in nematicide treated plots. Suppression of nematodes was higher under phorate (117 nematodes/200 g soil) than under carbofuran (126.7 nematodes/200 g soil) treatment. The number of juveniles parasitized was also influenced by nematicides and spore load carried/juvenile with phorate being superior and the increase being 17.0 and 29.0% respectively over the control. The results of these experiment confirmed the compatibility of P. penetrans with nematicides and its biological control potential against the root-knot nematode.

Animals↗
PubMedDate not supplied

[A comparison of the growth of 2 species of Pomacea from the Antilles area useful as an agent to control tropical diseases].

A comparative study was made on the growth of 2 Pomacea species (P. glauca and P. paludosa) of the Caribbean area. The occurrence of ecological differences reflected on the growth parameters is noted. These discrepancies may be influenced by differences in the physical-chemical and environmental status of the localities under study, but a clear-cut ecological difference between both species can be observed. Growth parameters (K and L phi), as well as the growth curves, suggest they are slow-growing species with a long life range. Differently from intermediate hosts, which are fast-growing species with a short life range, Pomacea species may keep stable populations in permanent bodies of water. It means an important advantage as biological control agents.

Animals↗
PubMed2006

Transfer and fate of seminal fluid molecules in the beetle, Diaprepes abbreviatus: implications for the reproductive biology of a pest species.

Molecules transferred from males to females via seminal fluids are important to the study of insect reproduction because they affect female physiology, reproductive behavior, and longevity. These molecules (seminal fluid molecules or SFMs) interest applied entomologists because of their potential use in insect control. SFMs are also interesting because of their relatively rapid evolution and important role in post-mating sexual selection. We studied SFMs in Diaprepes abbreviatus, a major pest of numerous plant species of economic importance. Using radiolabeled-methionine (35S), we found that D. abbreviatus males synthesized proteins de novo in their reproductive tissues after mating. Males that were fed radiolabeled methionine transferred radioactivity to females beginning within the first 10 min of mating. Male-derived substances are absorbed from the female's reproductive tract into the hemolymph and circulated throughout the body, but are found primarily in the eggs and ovaries. As a result, SFMs may be a useful means of both horizontal (to mates) and vertical transfer (to offspring) of control agents between conspecifics.

Animals↗
PubMed1991

Perspectives on management of pestiferous Chironomidae (Diptera), an emerging global problem.

In recent years, adult Chironomidae emerging from some urban natural or man-made habitats have increasingly posed a variety of nuisance and economic problems, and in some situations medical problems to humans in different parts of the world. Although there are an estimated 4,000 or more species of chironomid midges worldwide, less than 100 species have been reported to be pestiferous. Among midge control methods, numerous laboratory and field studies have been conducted on the use of organochlorines, organophosphates (OPs), pyrethroids and insect growth regulators (IGRs). Field use of OP insecticides such as chlorpyrifos, temephos and others in the USA and Japan has generally resulted in larval control for 2-5 wk or longer with application rates below 0.56 kg AI/ha (USA) and less than 1-5 ppm (Japan). Frequent use of some OP insecticides in the USA and Japan has caused their increased tolerance in several midge species. The IGRs, diflubenzuron and methoprene, provide alternate means for midge control. These IGRs in some situations suppressed adult midge emergence by greater than 90% at rates less than 0.3 kg AI/ha. A number of parasites and pathogens have been reported from midges in different parts of the world. Bacillus thuringiensis serovar. israelensis is effective against some midge species, but at rates at least 10x or higher established for mosquito larvicidal activity. The flatworm, Dugesia dorotocephala, and some fish species offer a good potential for midge control in some situations. In large habitats covering hundreds or thousands of ha, information on the basic ecology of larval midges and adult behavior is essential for formulating midge control criteria. More research is needed on the biological and physical and cultural control of these pestiferous insects.

Animals↗
PubMed1996

Construction of an improved mycoinsecticide overexpressing a toxic protease.

Mycoinsecticides are being used for the control of many insect pests as an environmentally acceptable alternative to chemical insecticides. A key aim of much recent work has been to increase the speed of kill and so improve commercial efficacy of these biocontrol agents. This might he achieved by adding insecticidal genes to the fungus, an approach considered to have enormous potential for the improvement of biological pesticides. We report here the development of a genetically improved entomopathogenic fungus. Additional copies of the gene encoding a regulated cuticle-degrading protease (Pr1) from Metarhizium anisopliae were inserted into the genome of M. anisopliae such that Pr1 was constitutively overproduced in the hemolymph of Manduca sexta, activating the prophenoloxidase system. The combined toxic effects of Pr1 and the reaction products of phenoloxidase caused larvae challenged with the engineered fungus to exhibit a 25% reduction in time of death and reduced food consumption by 40% compared to infections by the wild-type fungus. In addition, infected insects were rapidly melanized, and the resulting cadavers were poor substrates for fungal sporulation. Thus, environmental persistence of the genetically engineered fungus is reduced, thereby providing biological containment.

Amino Acid Sequence↗
PubMed2005

Development and reproduction of Adalia bipunctata (Coleoptera: Coccinellidae) on eggs of Ephestia kuehniella (Lepidoptera: Phycitidae) and pollen.

Due to growing criticism over the use of non-indigenous coccinellids, the two-spot ladybird, Adalia bipunctata (L.), has enjoyed increasing attention for aphid biocontrol in Europe. In the current study, eggs of the Mediterranean flour moth, Ephestia kuehniella Zeller, whether or not supplemented with bee pollen, were evaluated as a factitious food for larvae and adults of A. bipunctata. The predator showed slower larval development and lower survival when reared on live pea aphids, Acyrthosiphon pisum (Harris), than on E. kuehniella eggs. Survival on gamma-irradiated eggs of E. kuehniella was superior to that on frozen flour moth eggs, but other developmental characteristics were similar. Adults of A. bipunctata reared on Ac. pisum were only half as fecund as those offered irradiated or frozen E. kuehniella eggs, but egg hatch was markedly better on live aphids than on flour moth eggs (61 versus 20-27%, respectively). However, when a diet of flour moth eggs was supplemented with frozen moist bee pollen, egg hatch of A. bipunctata was equally as good as on live aphids. Supplementing flour moth eggs with dry pollen did not yield satisfactory results. Only 10% of larvae reached adulthood on moist bee pollen alone and resulting adults weighed less than half as much as those obtained on flour moth eggs. Our findings indicate that A. bipunctata is able to compensate for a suboptimal diet of animal prey by supplementary feeding on flower pollen. It is concluded that pollinivory may be a crucial trait for both the rearing of this natural enemy and its use in biological control programmes.

Animals↗
PubMed2006

Testing for non-target effects of spinosad on twospotted spider mites and their predator Phytoseiulus persimilis under greenhouse conditions.

The compatibility of the selective insecticide spinosad (Conserve SC), at rates recommended for thrips control in greenhouses, with release of the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) to control spider mites, was investigated in a crop of ivy geranium Pelargonium peltatum, cultivar 'Amethyst 96.' Plants were inoculated with twospotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae), 2 weeks before treatments were applied. There were three treatment variables, each at two levels: predators (released or not), spray application (water or Conserve SC at 2 ml/3.79 l), and timing of spray (1 day before or after predators were released). Twospotted spider mite populations then were sampled twice each week over a three-week period. The application or timing of spinosad had no effect on the ability of the predator to reduce the population of spider mites. Spider mite populations in the no-predator treatment continued to expand over the course of the experiment, while those in the predator-release treatment declined. We conclude that P. persimilis can be used in conjunction with spinosad on ivy geraniums without causing obvious detrimental effects to this predator or leading to a reduction in biological control.

Animals↗