6 research outputs found
Scale of association between <i>Lygus</i> density in cotton fields and abundance of surrounding habitats.
<p>Average scale (mean + SE) for habitats found to have significant effects in a least two of the six analyses are shown. Standard errors were derived from the ANOVA.</p
Characteristics of cotton fields sampled for western tarnished plant bug, <i>Lygus hesperus.</i>
<p>Variables shown are average field area (ha), average closest distance between pairs of sampled cotton fields (km), date of initiation of first and second sampling periods, average date of initiation of flowering, percentage of sampled fields planted to Pima cotton, average number of insecticide sprays and average <i>Lygus</i> density (calculated per 100 sweeps to facilitate comparison with thresholds) for combined sampling periods in each year.</p>*<p>Number of fields sampled: 41 in 2007; 39 in 2008; 56 in 2009.</p>†<p>Standard error in parentheses.</p>‡<p>Date is for onset of sampling period; number of weeks sampled per period is in parentheses.</p>¶<p>Range associated with average flowering date was 22 Jun–7 Jul in 2007, 7 Jul–12 Jul in 2008, and 17 Jun–2 Jul in 2009.</p>§<p>Suggested thresholds for <i>Lygus</i> spraying depend on cotton phenology <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039862#pone.0039862-UC1" target="_blank">[48]</a>. Number of individuals per 100 sweeps that would trigger spraying is: >4–8 adults (early squaring); >14–20 individuals with at least two nymphs (bloom); and >20 individuals with nymphs present (boll filling).</p
Bt protein levels in Bt crops (broccoli, cotton and maize), prey (<i>Trichoplusia ni</i> and <i>Spodoptera frugiperda</i>) and the predator (3rd instar <i>Chrysoperla rufilabris</i>).
<p>Means (± SE) within a column followed by different letters are significantly different (One-way ANOVA, <i>P</i><0.05); N = 3.</p><p>Prey: <i>T. ni</i> for broccoli and cotton, <i>S. frugiperda</i> for maize. FW: Fresh weight. Note that unit for leaves and prey is µg/g FW and for <i>C. rufliabris</i> ng/g FW.</p
Tri-trophic effects on life table parameters (means ± SE) of <i>Chrysoperla rufilabris</i> when fed <i>Trichoplusia ni</i> larvae that were reared on Cry1Ac-producing broccoli leaves or non-Bt broccoli leaves over two generations.
<p>Number of replications is given in parenthesis. The experiment started with 30 larvae in each treatment.</p>*<p>Wilcoxon test (<i>P</i><0.05).</p>†<p>One-way ANOVA (<i>P</i><0.05).</p
Tri-trophic effects on life table parameters (means ± SE) of <i>Chrysoperla rufilabris</i> when fed Cry1F-resistant <i>Spodoptera frugiperda</i> larvae that were reared on Cry1F-producing maize leaves or non-Bt maize leaves over two generations.
<p>Number of replications is given in parenthesis. The experiment started with 50 larvae in both treatments.</p>*<p>Wilcoxon test (<i>P</i><0.05).</p>†<p>Student’s <i>t</i>-test (<i>P</i><0.05).</p
Bioactivity to Bt-susceptible <i>Plutella xylostella</i> larvae to Bt proteins residues from <i>Trichoplusia ni</i> reared on Cry1Ac broccoli or on Cry1Ac/Cry2Ab cotton leaves and from <i>Spodoptera frugiperda</i> reared on Cry1F maize leaves<b>.</b>
<p>A total of 50 susceptible <i>P. xylostella</i> larvae were used in each treatment with 5 replications (10 larvae/replication). Mortality assessed after 72 h. Means followed by different letters are significantly different (One-way ANOVA, <i>P</i><0.05).</p