Impact of planting date and varietal maturity on tarnished plant bug (Hemiptera: Miridae) in cotton

A field experiment was conducted in Stoneville, MS, during 2010 and 2011 to investigate the impact of varietal maturity, planting date, and insecticide application on tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), populations and damage in cotton. Four planting dates were selected to encompass the cotton-planting period in Mississippi. An early and late maturing variety were planted at each planting date, and each variety and planting date combination was either sprayed or unsprayed for tarnished plant bugs. Plots were sampled weekly from first square until physiological maturity. Plots were harvested at the end of the season. Early planting dates had lower densities of tarnished plant bug and required fewer insecticide applications than the later planting dates. Mid-April to early May planting dates sustained less yield loss from tarnished plant bug than mid-May to late-May planting dates. Tarnished plant bug had less impact on yield of the early maturing variety than on the late maturing variety. The sprayed plots yielded more than unsprayed plots. These data demonstrate that later plantings of cotton in the Mississippi Delta are likely to experience yield losses from tarnished plant bug and need to be sprayed more compared with early cotton plantings. As a result, growers should manage their crop for earliness through planting date and varietal selection.

Cotton aphid (Heteroptera: Aphididae) susceptibility to commercial and experimental insecticides in the southern United States

Cotton aphid, Aphis gossypii Glover, has a history of developing resistance to novel insecticides. A program is needed to monitor cotton aphid susceptibility to new insecticides. Concentration-mortality bioassays were conducted from 2008 to 2011 to monitor the susceptibility of cotton aphids from fields across the midsouthern United States to thiamethoxam and sulfoxaflor. Flonicamid was included in 2010 and 2011. Bioassays followed the procedures described by the Insecticide Resistance Action Committee for testing neonicotinoids against cotton aphid. Mortality was rated at 48 and 72 h. These bioassays suggest that high levels of resistance to thiamethoxam occur in cotton aphid throughout the midsouthern United States. Resistance ratios ranged from 0.9 to 562.6 at 48 h, and from 0.9 to 29.1 at 72 h. Aphid colonies tested were considered susceptible to flonicamid and sulfoxaflor. The LC50 values ranged from 1.43 to 6.60 ppm for flonicamid. The LC50 values for sulfoxaflor ranged from 1.01 to 5.85 ppm and 0.92-4.13 ppm at 48 and 72 h, respectively. These values represent the baseline variability of the susceptibility of cotton aphid to flonicamid and sulfoxaflor. The moderate level of variability observed combined with the high level of efficacy at low rates and the high reproductive rate of cotton aphid suggests that an effective resistance management plan needs to be devised for these insecticides. Flonicamid and sulfoxaflor should provide effective control of cotton aphid in areas where thiamethoxam resistance occurs. However, these insecticides need to be incorporated into a rotation strategy to preserve their efficacy against cotton aphid.

Macimorelin (AEZS-130)-stimulated growth hormone (GH) test: validation of a novel oral stimulation test for the diagnosis of adult GH deficiency

CONTEXT

In the absence of panhypopituitarism and low serum IGF-I levels, the diagnosis of adult GH deficiency (AGHD) requires confirmation with a GH stimulation test. Macimorelin is a novel, orally active ghrelin mimetic that stimulates GH secretion.

OBJECTIVE

The objective of the study was to determine the diagnostic efficacy and safety of macimorelin in AGHD.

DESIGN

This was a multicenter open-label study comparing the diagnostic accuracy of oral macimorelin with that of arginine+GHRH in AGHD patients and healthy, matched controls. After 43 AGHD patients and 10 controls were tested, the GHRH analog Geref Diagnostic [GHRH(1-29)NH2] became unavailable in the United States. The study was completed by testing 10 additional AGHD patients and 38 controls with macimorelin alone.

MAIN OUTCOME MEASURE

Peak GH area under the receiver operating characteristic curve after macimorelin was measured.

RESULTS

Fifty AGHD subjects and 48 controls were evaluated. Peak GH levels in AGHD patients and controls after macimorelin were 2.36 ± 5.69 and 17.71 ± 19.11 ng/mL, respectively (P < .0001). With macimorelin, the receiver operating characteristic analysis yielded an optimal GH cut point of 2.7 ng/mL, with 82% sensitivity, 92% specificity, and 13% misclassification rate. For subjects receiving both tests, macimorelin showed discrimination comparable with arginine+GHRH (area under the receiver operating characteristic curve 0.99 vs 0.94, respectively, P = .29). Obesity (body mass index > 30 kg/m(2)) was present in 58% of subjects, and peak GH levels were inversely associated with body mass index in controls (r = -0.37, P = .01). Using the separate cut points of 6.8 ng/mL for nonobese and 2.7 for obese subjects reduced the misclassification rate to 11%. Only 1 drug-related serious adverse event, an asymptomatic QT interval prolongation on the electrocardiogram, was reported.

CONCLUSION

Oral macimorelin is safe, convenient, and effective in diagnosing AGHD with accuracy comparable with the arginine+GHRH test.

Impact of twospotted spider mite (Acari: Tetranychidae) duration of infestation on cotton seedlings

The yield response of cotton, Gossypium hirsutum L., to twospotted spider mite, Tetranychus urticae Koch, duration of infestation during the seedling stage was measured at Starkville and Stoneville, MS, during 2010 and 2011. The treatments included a noninfested control, infestations lasting for 7, 14, 21, or 28 d, and a season long infested control. Twospotted spider mites from a greenhouse colony were inoculated on all of the infested cotton plots during the three-leaf stage. Applications of miticides were made to terminate infestations at the desired timings for each treatment. Twospotted spider mite densities and injury ratings were determined for each treatment at the end of the infestation period and yield was measured at the end of the season. Twospotted spider mite densities and injury rating significantly increased as duration of infestation increased. Significant differences in yield were observed between treatments. These data suggest infestations initiated at the three-leaf cotton growth stage with population densities at a minimum of 0.39 mites/cm2 existing > 14 d could result in reduction of cotton yields.

Graphical Tests for Power Comparison of Competing Designs

Lineups have been established as tools for visual testing similar to standard statistical inference tests, allowing us to evaluate the validity of graphical findings in an objective manner. In simulation studies lineups have been shown as being efficient: the power of visual tests is comparable to classical tests while being much less stringent in terms of distributional assumptions made. This makes lineups versatile, yet powerful, tools in situations where conditions for regular statistical tests are not or cannot be met. In this paper we introduce lineups as a tool for evaluating the power of competing graphical designs. We highlight some of the theoretical properties and then show results from two studies evaluating competing designs: both studies are designed to go to the limits of our perceptual abilities to highlight differences between designs. We use both accuracy and speed of evaluation as measures of a successful design. The first study compares the choice of coordinate system: polar versus cartesian coordinates. The results show strong support in favor of cartesian coordinates in finding fast and accurate answers to spotting patterns. The second study is aimed at finding shift differences between distributions. Both studies are motivated by data problems that we have recently encountered, and explore using simulated data to evaluate the plot designs under controlled conditions. Amazon Mechanical Turk (MTurk) is used to conduct the studies. The lineups provide an effective mechanism for objectively evaluating plot designs.

Directional limits on persistent gravitational waves using LIGO S5 science data

The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2-20×10(-50)  strain(2) Hz(-1) and 5-35×10(-49)  strain(2) Hz(-1) sr(-1) for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW strain from interesting targets including Sco X-1, SN 1987A and the Galactic center as low as ≈7×10(-25) in the most sensitive frequency range near 160 Hz.