| optimization of cry3a yields in bacillus thuringiensis by use of sporulation-dependent promoters in combination with the stab-sd mrna sequence. | the insecticidal activity of bacillus thuringiensis strains toxic to coleopterous insects is due to cry3 proteins assembled into small rectangular crystals. toxin synthesis in these strains is dependent primarily upon a promoter that is active in the stationary phase and a stab-sd sequence that stabilizes the cry3 transcript-ribosome complex. here we show that significantly higher yields of cry3a can be obtained by using dual sporulation-dependent cyt1aa promoters to drive the expression of cry3 ... | 1998 | 9758822 |
| cyt1aa protein of bacillus thuringiensis is toxic to the cottonwood leaf beetle, chrysomela scripta, and suppresses high levels of resistance to cry3aa | the insecticidal activity of bacillus thuringiensis is due primarily to cry and cyt proteins. cry proteins are typically toxic to lepidopterous, coleopterous, or dipterous insects, whereas the known toxicity of cyt proteins is limited to dipterans. we report here that a cyt protein, cyt1aa, is also highly toxic to the cottonwood leaf beetle, chrysomela scripta, with a median lethal concentration of 2.5 ng/mm2 of leaf surface for second-instar larvae. additionally, we show that cyt1aa suppresses ... | 1998 | 9797292 |
| enhanced toxicity of bacillus thuringiensis cry3a delta-endotoxin in coleopterans by mutagenesis in a receptor binding loop. | we used site-directed mutagenesis to modify the bacillus thuringiensis cry3a gene in amino acid residues 350-354. two mutant toxins, a1 (r(345)a,y(350)f,y(351)f) and a2 (r(345)a,deltay(350), deltay(351)), showed significantly improved toxicity against tenebrio molitor (yellow mealworm). the mutant toxin a1 was also more potent against both leptinotarsa decemlineata (colorado potato beetle) and chrysomela scripta (cottonwood leaf beetle), while a2 displayed enhanced toxicity only in l. decemlinea ... | 2000 | 10812080 |
| laboratory and field evaluations of two bacillus thuringiensis formulations, novodor and raven, for control of cottonwood leaf beetle (coleoptera: chrysomelidae). | laboratory and field experiments were conducted to determine the efficacy of two bacillus thuringiensis berliner formulations, novodor and raven, for controlling cottonwood leaf beetle, chrysomela scripta f. (coleoptera: chrysomelidae). in laboratory bioassays, larvae or adults were added to petri dishes containing populus x euramericana guinier 'eugenei' foliage that had been treated with distilled water (control) or one of the commercial bt formulations at either high or low label rates. survi ... | 2000 | 10902320 |
| characterization of a bacillus thuringiensis delta-endotoxin which is toxic to insects in three orders. | we report here the first bacillus thuringiensis (bt) toxin which is toxic to insects from three insect orders (diptera, coleoptera, and lepidoptera). an oligonucleotide probe based on the delta-endotoxin n-terminal sequence was used to detect the gene. a 23-kb bamhi fragment containing the intact gene was identified and cloned from bt strain ybt-226 plasmid dna into the vector pbluescript ii. through a series of dna manipulations the size of this fragment was reduced and the gene sequenced. the ... | 2000 | 11023737 |
| management of cottonwood leaf beetle (coleoptera: chrysomelidae) with a novel transplant soak and biorational insecticides to conserve coccinellid beetles. | biorational foliar sprays and a novel application method of soaking transplants in imidacloprid were evaluated for control of adult and larval cottonwood leaf beetle, chrysomela scripta f., on hybrid poplar, with emphasis on conservation of coccinellid predators. foliar sprays of four biorational insecticides killed adult and larval c. scripta: bacillus thuringiensis (b.t.) variety tenebrionis (novodor), b.t. variety kurstaki (raven), spinosad (conserve sc), and azadirachtin (azatin xl) (larvae ... | 2006 | 16573329 |
| sources of insect and plant volatiles attractive to cottonwood leaf beetles feeding on hybrid poplar. | the cottonwood leaf beetle, chrysomela scripta, is the most damaging insect affecting the production of populus, an important source of sustainable forest products and biomass. currently, there is no simple method for monitoring c. scripta populations, and nothing is known about potential chemical attractants for trapping. we conducted laboratory assays on sources of attraction to c. scripta adults. in olfactometer trials, beetles were attracted to volatiles released from conspecifics feeding on ... | 2006 | 17089182 |
| cry1b and cry3a are active against hypothenemus hampei ferrari (coleoptera: scolytidae). | cry1b and cry3 proteins from bacillus thuringiensis are toxic to beetles such as the colorado potato beetle and the cottonwood leaf beetle. we report the development of a suitable rearing, bioassay method and the toxicity of these cry proteins to coffee berry borer first instar larvae. | 2009 | 19465024 |
| allozyme gene diversities in some leaf beetles (coleoptera: chrysomelidae). | gene diversity at allozyme loci was investigated in the bean leaf beetle, ceratoma trifurcata forster; the elm leaf beetle, xanthogaleruca luteola (muller); the cottonwood leaf beetle, chrysomela scripta fabricus; the western corn rootworm, diabrotica virgifera virgifera leconte; the southern corn rootworm, also called the spotted cucumber beetle, d. undecimpunctata howardi baker; the northern corn rootworm, d. barberi smith and lawrence; and the colorado potato beetle, leptinotarsa decemlineata ... | 1999 | 10624512 |
| relative importance of genetic, ontogenetic, induction, and seasonal variation in producing a multivariate defense phenotype in a foundation tree species. | plant adaptations for defense against herbivory vary both among species and among genotypes. moreover, numerous forms of within-plant variation in defense, including ontogeny, induction, and seasonal gradients, allow plants to avoid expending resources on defense when herbivores are absent. we used an 18-year-old cottonwood common garden composed of populus fremontii, populus angustifolia, and their naturally occurring f(1) hybrids (collectively referred to as "cross types") to quantify and comp ... | 2012 | 22652923 |
| comparison of standard (granular and drench) and novel (tablet, stick soak, and root dip) imidacloprid treatments for cottonwood leaf beetle (coleoptera: chrysomelidae) management on hybrid poplar. | standard soil application methods (granular and drench) were compared with novel methods (tablet, stick soak, and root dip) for efficacy and duration in hybrid poplar (populus spp.) against adult and larval cottonwood leaf beetle, chrysomela scripta f. (coleoptera: chrysomelidae). beetle feeding can kill saplings and significantly damage trees by reducing tree height, diameter, and biomass. tablets offer lower risk to applicators and beneficial insects, because insecticides do not need to be mea ... | 2007 | 17972639 |
| leaf chemical changes induced in populus trichocarpa by enhanced uv-b radiation and concomitant effects on herbivory by chrysomela scripta (coleoptera: chrysomelidae). | to assess the potential impact of enhanced ultraviolet-b (uv-b) radiation over two trophic levels, we monitored key leaf chemical constituents and related changes in their concentration to dietary preference and performance of a specialist insect herbivore. ramets of populus trichocarpa torr. & gray (black cottonwood) were subjected to near zero (0x), ambient (1x) or twice ambient (2x) doses of biologically effective uv-b radiation (uv-b(be)) in a randomized block design using either a square-wa ... | 2002 | 12414373 |
| economic injury level for second-generation cottonwood leaf beetle (coleoptera: chrysomelidae) in two-year-old populus. | the cottonwood leaf beetle, chrysomela scripta f., is a major defoliating pest of populus in north america. as the use of populus in short-rotation woody crop plantations continues to increase, there are increasing economic and environmental needs to develop rational pest management programs to reduce the impact of this insect. our objective was to determine the economic injury levels for the second generation of the cottonwood leaf beetle during plantation establishment. integrating the cost of ... | 2002 | 12020006 |
| gene diversity at allozyme loci in the cottonwood leaf beetle, chrysomela scripta. | gene diversity was studied in beetles collected from a poplar plantation at ames, iowa. the beetles are widely distributed throughout north america wherever poplars (populus spp) occur. of 38 loci interpretable by simple mendelian criteria, 22 were polymorphic (58%). nei's mean heterozygosity per locus was 20.1 +/- 4.0%. a mean 2.29 +/- 1.35 alleles per locus was detected. the foregoing levels of diversity are typical of coleoptera. there were significant deviations from hardy-weinberg expectati ... | 1995 | 7677732 |
| methyl parathion and carbarly resistance in chrysomela scripta and coleomegilla maculata. | | 1977 | 402963 |