Corn rootworms (Coleoptera: Chrysomelidae) in space and time

Spatial dispersion is a main characteristic of insect populations. Dispersion pattern provides useful information for developing effective sampling and scouting programs because it affects sampling accuracy, efficiency, and precision. Insect dispersion, however, is dynamic in space and time and largely dependent upon interactions among insect, plant and environmental factors. This study investigated the spatial and temporal dynamics of corn rootworm dispersion at different spatial scales by using the global positioning system, the geographic information system, and geoStatistics and Probability; Egg dispersion pattern was random or uniform in 8-ha cornfields, but could be aggregated at a smaller scale. Larval dispersion pattern was aggregated regardless of spatial scales used in this study. Soil moisture positively affected corn rootworm egg and larval dispersions. Adult dispersion tended to be aggregated during peak population period and random or uniform early and late in the season and corn plant phenology was a major factor to determine dispersion patterns. The dispersion pattern of root injury by corn rootworm larval feeding was aggregated and the degree of aggregation increased as the root injury increased within the range of root injury observed in microscale study. Between-year relationships in dispersion among eggs, larvae, adult, and environment provided a strategy that could predict potential root damage the subsequent year. The best prediction map for the subsequent year\u27s potential root damage was the dispersion maps of adults during population peaked in the cornfield. The prediction map was used to develop site-specific pest management that can reduce chemical input and increase control efficiency by controlling pests only where management is needed. This study demonstrated the spatio-temporal dynamics of insect population and spatial interactions among insects, plants, and environment

Effect of Plant Characteristics and Within-Plant Distribution of Prey on Colonization Efficiency of Cryptolaemus montrouzieri

Cryptolaemus montrouzieri (Coleoptera: Coccinellidae) has been widely used in classical and inundative biological control of mealybugs, including the long-tailed mealybug, Pseudococcus longispinus (Hemiptera: Pseudococcidae). This study was conducted to investigate colonization and establishment efficiency of C. montrouzieri to manage P. longispinus on three different ornamental plant species (Ficus elastica, Lilium longiflorum, and Dieffenbachia seguine). Within-plant distribution pattern of P. longispinus and the colonization ecology of adult C. montrouzieri were investigated. Significantly more P. longispinus were found on the upper parts of the plants regardless of plant species, and C. montrouzieri adults discovered P. longispinus significantly faster when they were released on the top of the plants than on the bottom. Choice tests revealed that C. montrouzieri adults preferred smaller P. longispinus nymphs. The implications for utilization of C. montrouzieri for biological control of mealybugs on various ornamental plants are discussed

Assessing the Effectiveness of Corn Rootworm Control and Areawide Management of Corn Rootworms

Corn rootworm populations have been high the last couple of seasons. The higher density of the pest generates questions concerning the effectiveness of corn rootworm controls that have been used, especially insecticides. Corn rootworm infestations, and their injury, tend to be variable (spotty) across a field of corn. If more then a node of roots has been destroyed and there is a wind, the corn is likely to be lodged. The lodging provides a visual manifestation of the corn rootworm larval feeding. Because the infestations are not uniform across a field, the lodging is also variable. If one were to want to obtain the worst possible root-injury rating for the field, they would select lodged plants to dig and rate. If one wanted to produce a lower rating, say if they were responsible for the product applied to control the rootworm, they could choose plants that were not lodged. Therefore the rating of corn rootworm larval injury to corn can be biased by selectively sampling plants based on the above ground appearance, lodged or not lodged. To be fair to growers AND the vendor of a rootworm control product, an unbiased sampling program should be used

Genetic Diversity of Halyomorpha halys (Hemiptera, Pentatomidae) in Korea and Comparison with COI Sequence Datasets from East Asia, Europe, and North America

The brown marmorated stinkbug, Halyomorpha halys, is an invasive insect pest in North America and Europe that attacks crop species and causes substantial economic damage. To evaluate the genetic diversities and distributions of different H. halys populations in East Asia, North America, and Europe, COI sequences obtained from 79 new specimens from Korea and 10 from the USA were compared with 725 existing COI sequences. In total, 45 haplotypes were detected in populations from 10 countries. Sixteen haplotypes from Korea (H34–H49) and 2 from the USA (H50 and H51) were novel. Korean populations exhibited the 2nd highest diversity among the 10 countries, with only Greece exhibiting higher diversity. Haplotype H22 was prominent in Korea, H1 was prominent in China, Greece, Hungary, Italy, Canada, and USA, and H3 was prominent in France and Switzerland. Of the 18 haplotypes found in Korea, 1 was shared with China (H2) and 1 with Greece (H22). Haplotype diversity patterns showed that Korean populations were genetically distinct from populations in China, Europe, and North America. This suggested that populations in Europe and North America arose through multiple invasions from China and that (with the exception of Greece), Korean populations did not spread to other countries. This study represents a comprehensive analysis of H. halys populations in Korea and places these populations in a global context that includes other native populations in East Asia and invasive populations in Europe and North America

Effects of Temperature on Development and Voltinism of Chaetodactylus krombeini (Acari: Chaetodactylidae): Implications for Climate Change Impacts

Temperature plays an important role in the growth and development of arthropods, and thus the current trend of climate change will alter their biology and species distribution. We used Chaetodactylus krombeini (Acari: Chaetodactylidae), a cleptoparasitic mite associated with Osmia bees (Hymenoptera: Megachilidae), as a model organism to investigate how temperature affects the development and voltinism of C. krombeini in the eastern United States. The effects of temperature on the stage-specific development of C. krombeini were determined at seven constant temperatures (16.1, 20.2, 24.1, 27.5, 30.0, 32.4 and 37.8°C). Parameters for stage-specific development, such as threshold temperatures and thermal constant, were determined by using empirical models. Results of this study showed that C. krombeini eggs developed successfully to adult at all temperatures tested except 37.8°C. The nonlinear and linear empirical models were applied to describe quantitatively the relationship between temperature and development of each C. krombeini stage. The nonlinear Lactin model estimated optimal temperatures as 31.4, 32.9, 32.6 and 32.5°C for egg, larva, nymph, and egg to adult, respectively. In the linear model, the lower threshold temperatures were estimated to be 9.9, 14.7, 13.0 and 12.4°C for egg, larva, nymph, and egg to adult, respectively. The thermal constant for each stage completion were 61.5, 28.1, 64.8 and 171.1 degree days for egg, larva, nymph, and egg to adult, respectively. Under the future climate scenarios, the number of generations (i.e., voltinism) would increase more likely by 1.5 to 2.0 times by the year of 2100 according to simulation. The findings herein firstly provided comprehensive data on thermal development of C. krombeini and implications for the management of C. krombeini populations under global warming were discussed

Facile Synthesis of Porous Silicon Nanofibers by Magnesium Reduction for Application in Lithium Ion Batteries

We report a facile fabrication of porous silicon nanofibers by a simple three-stage procedure. Polymer/silicon precursor composite nanofibers are first fabricated by electrospinning, a water-based spinning dope, which undergoes subsequent heat treatment and then reduction using magnesium to be converted into porous silicon nanofibers. The porous silicon nanofibers are coated with a graphene by using a plasma-enhanced chemical vapor deposition for use as an anode material of lithium ion batteries. The porous silicon nanofibers can be mass-produced by a simple and solvent-free method, which uses an environmental-friendly polymer solution. The graphene-coated silicon nanofibers show an improved cycling performance of a capacity retention than the pure silicon nanofibers due to the suppression of the volume change and the increase of electric conductivity by the graphene.Korea Institute of Energy Technology Evaluation and Planning (Human Resources Development Program Grant 20144030200600

Spatial and Temporal Distribution of Imidacloprid Within the Crown of Eastern Hemlock

Systemic imidacloprid is the most widely used insecticide to control the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), an exotic pest of eastern hemlock, Tsuga canadensis (L.) Carriére in the United States. This study was conducted to 1) determine the effect of treatment timing (spring vs. fall) and application method (trunk injection vs. soil injection) on the spatial and temporal distribution of imidacloprid within the crown of A. tsugae-free eastern hemlock using a competitive enzyme-linked immunosorbent assay (ELISA), 2) compare ELISA to gas chromatography-mass spectrometry (GC/MS) for the detection of imidacloprid in xylem fluid, and 3) determine the concentration of imidacloprid in leaf tissue using high performance liquid chromatography with tandem mass spectrometric (LC/MS/MS) detection methods. Xylem fluid concentrations of imidacloprid were found to be significantly higher for spring applications than for fall applications and for trunk injections than soil injections in the first year posttreatment. A total of 69% of samples analyzed by ELISA gave 1.8 times higher concentrations of imidacloprid than those found by GC/MS, leading to evidence of a matrix effect and overestimation of imidacloprid in xylem fluid by ELISA. A comparison of the presence of imidacloprid with xylem fluid and in leaf tissue on the same branch showed significant differences, suggesting that imidacloprid moved intermittently within the crown of eastern hemlock

Normal Ambulatory 24-Hour Esophageal pH Values in Koreans -A Multicenter Study-

Ambulatory 24-hr esophageal pH monitoring is considered the gold standard for diagnosing gastroesophageal reflux disease. The aim of this study was to establish normal values for gastroesophageal acid exposure in healthy Koreans. Fifty healthy volunteers (24 males and 26 females; mean age, 45 yr) without reflux symptoms and without reflux esophagitis or hiatal hernia on upper endoscopy underwent ambulatory 24-hr esophageal pH monitoring after esophageal manometry. The 95th percentiles for the reflux parameters were: the percent total time pH <4, 3.7%; the percent upright time pH <4, 5.7%; the percent supine time pH <4, 1.0%; the number of reflux episodes with pH <4, 76.5; the number of reflux episodes with pH <4 for >5 min, 1.5; the duration of the longest episode, 12.5 min; and the composite score, 14.2. Age and gender were not associated with any of the pH parameters. In conclusion, physiological gastroesophageal reflux occurs in healthy Koreans. These normal esophageal pH values will provide reference data for clinical and research studies in Korea

Successful Treatment of Protein-Losing Enteropathy Induced by Intestinal Lymphangiectasia in a Liver Cirrhosis Patient with Octreotide: A Case Report

A 47-yr-old man with hepatitis B virus associated liver cirrhosis was admitted to our hospital with diarrhea and generalized edema and diagnosed as protein-losing enteropathy due to intestinal lymphangiectasia by intestinal biopsy and 99mTc albumin scan. During hospitalization, he received subcutaneous octreotide therapy. After 2 weeks of octreotide therapy, follow-up albumin scan showed no albumin leakage, and the serum albumin level was sustained. We speculate that liver cirrhosis can be a cause of intestinal lymphangiectasia and administration of octreotide should be considered for patients with intestinal lymphangiectasia whose clinical and biochemical abnormalities do not respond to a low-fat diet