biological activity of natural phytoecdysteroids from ajuga iva against the sweetpotato whitefly bemisia tabaci and the persea mite oligonychus perseae.background: ecdysteroids are steroid hormones that control moulting and govern several changes during metamorphoses in arthropods. the discovery of the same molecules (phytoecdysteroids) in several plant species displayed a wide array of rather beneficial agricultural impact. many representatives of the genus ajuga plants contain phytoecdysteroids with a 5β-7-ene-6-one system exhibiting physiological activities in insects. results: by means of chromatographic (silica gel column, tlc) and lc-ms, ...201121604353
permanent genetic resources added to molecular ecology resources database 1 january 2009-30 april 2009.this article documents the addition of 283 microsatellite marker loci to the molecular ecology resources database. loci were developed for the following species: agalinis acuta; ambrosia artemisiifolia; berula erecta; casuarius casuarius; cercospora zeae-maydis; chorthippus parallelus; conyza canadensis; cotesia sesamiae; epinephelus acanthistius; ficedula hypoleuca; grindelia hirsutula; guadua angustifolia; leucadendron rubrum; maritrema novaezealandensis; meretrix meretrix; nilaparvata lugens; ...200921564911
predatory behaviors of neoseiulus californicus and galendromus helveolus (acari: phytoseiidae) attacking oligonychus perseae (acari: tetranychidae).predatory behaviors of neosieulus californicus (mcgregor) and galendromus helveolus (chant) attacking oligonychus perseae tuttle, baker and abbatiello on avocado leaves were videotaped and analyzed. behaviors were recorded for "fresh" predators that were used < or = 48 hr post receipt from a commercial insectary and "cold stored" predators that were maintained at 12 degrees c for approximately 14 days. fresh and cold stored g. helveolus were observed to attack o. perseae only after invading webb ...200212475074
contrasting effects of geographical separation on the genetic population structure of sympatric species of mites in avocado orchards.oligonychus punicae and oligonychus perseae (acari: tetranychidae) are the most important mite species affecting avocado orchards in mexico. here we used nucleotide sequence data from segments of the nuclear ribosomal internal transcribed spacers (its1 and its2) and mitochondrial cytochrome oxidase subunit i (coi) genes to assess the phylogenetic relationships between both sympatric mite species and, using only its sequence data, examine genetic variation and population structure in both species ...201424871093
sequential hypothesis testing with spatially correlated presence-absence data.a pest management decision to initiate a control treatment depends upon an accurate estimate of mean pest density. presence-absence sampling plans significantly reduce sampling efforts to make treatment decisions by using the proportion of infested leaves to estimate mean pest density in lieu of counting individual pests. the use of sequential hypothesis testing procedures can significantly reduce the number of samples required to make a treatment decision. here we construct a mean-proportion re ...201222812150
baseline susceptibility of persea mite (acari: tetranychidae) to abamectin and milbemectin in avocado groves in southern california.persea mite, oligonychus perseae tuttle, baker, and abatiello, susceptibility to abamectin and milbemectin was evaluated in 2003 to determine baseline susceptibility levels in avocado groves in san diego and ventura counties (california, usa) where more than 70% of the state's avocado production is concentrated. milbemectin has yet to be used in avocado production in california and abamectin has been available for use since 1999. baseline susceptibility ratios (in relation to the most susceptibl ...200516082923
how do neoseiulus californicus (acari: phytoseiidae) females penetrate densely webbed spider mite nests?the persea mite oligonychus perseae is a pest of avocado trees that builds extremely dense webbed nests that protect them against natural enemies, including phytoseiid mites. nests have one or two marginal entrances that are small and flattened. the predatory mite neoseiulus californicus co-occurs with o. perseae in the avocado orchards of the south-east of spain. penetration inside nests through the entrances by this predator is thought to be hindered by its size and its globular-shaped body. h ...200818347919
comparison and field validation of binomial sampling plans for oligonychus perseae (acari: tetranychidae) on hass avocado in southern california.oligonychus perseae tuttle, baker, & abatiello is a foliar pest of 'hass' avocados [persea americana miller (lauraceae)]. the recommended action threshold is 50-100 motile mites per leaf, but this count range and other ecological factors associated with o. perseae infestations limit the application of enumerative sampling plans in the field. consequently, a comprehensive modeling approach was implemented to compare the practical application of various binomial sampling models for decision-making ...201526470355
sampling method evaluation and empirical model fitting for count data to estimate densities of oligonychus perseae (acari: tetranychidae) on 'hass' avocado leaves in southern california.oligonychus perseae (acari: tetranychidae) is an important foliar spider mite pest of 'hass' avocados in several commercial production areas of the world. in california (usa), o. perseae densities in orchards can exceed more than 100 mites per leaf and this makes enumerative counting prohibitive for field sampling. in this study, partial enumerative mite counts along half a vein on an avocado leaf, an industry recommended practice known as the "half-vein method", was evaluated for accuracy using ...201626861068
spatial dependence and sampling of phytoseiid populations on hass avocados in southern california.research on phytoseiid mites has been critical for developing an effective biocontrol strategy for suppressing oligonchus perseae tuttle, baker, and abatiello (acari: tetranychidae) in california avocado orchards. however, basic understanding of the spatial ecology of natural populations of phytoseiids in relation to o. perseae infestations and the validation of research-based strategies for assessing densities of these predators has been limited. to address these shortcomings, cross-sectional a ...201627106820
differential host plant-associated genetic variation between sympatric mite species of the genus oligonychus (acari: tetranychidae).adaptation to different host plants can lead to host-associated differentiation (had). the mites oligonychus perseae and oligonychus punicae have a broad range of host plants, but, to date, records of them coexisting sympatrically had only been reported on avocado. however, our field observations showed both species coexisting on host plants other than avocado. the lack of previous records of these mites on the host plants studied here suggests only recent divergence to new host plant species. p ...201728087579
isolation and characterization of polymorphic microsatellite markers in tetranychus urticae and cross amplification in other tetranychidae and phytoseiidae species of economic importance.tetranychus urticae koch is a cosmopolitan phytophagous mite considered as the most polyphagous species among spider mites. population genetic studies using molecular markers such as microsatellites have proven to be extremely informative to address questions about population structure, phylogeography and host preferences. the aim of this study was to increase the available molecular tools to gain insight into the genetic structure of t. urticae populations of citrus orchards, which might help i ...201222349944
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