Identification and field bioassays of the sex pheromone of the yellow-legged clearwing Synanthedon vespiformis (Lepidoptera: Sesiidae)

The yellow-legged clearwing (YLC) Synanthedon vespiformis (Lepidoptera: Sesiidae) occurs in the Mediterranean and central Europe. It is polyphagous, boring into the woody parts of broadleaf species including forest trees as well as various Rosaceae species. S. vespiformis has been reported as an economically important pest causing severe injury to stone fruit plantations. Many attractants for sesiid species were discovered by random field screening using 2,13- and 3,13-octadecadienyl alcohols, acetates and aldehydes, including one for S. vespiformis; and about 20 sex pheromones of sesiids have been identified so far. In the present study we identified the natural composition of the sex pheromone of YLC laboratory reared females as a blend of E3,Z13- and Z3,Z13-octadecadienyl acetates, at a ratio of 4:1. We developed an efficient lure for monitoring the pest. Pheromone funnel traps with rubber septa, impregnated with 1 mg pheromone blend, efficiently captured males for 10 weeks. Suspension of Shin-Etsu^? ropes containing a 2:1 blend of E3,Z13-18:Ac and Z3,Z13-18:Ac at 13.74 mg/ha/h, resulted in shutdown of trap catches in the treated plots and closely situated neighboring plots indicating that mating disruption is feasible.     

Use of geographic information systems for assessing groundwater pollution potential by pesticides in Central Thailand

This study employed geographic information systems (GIS) technology to evaluate the vulnerability of groundwater to pesticide pollution in Thailand. The study area included three provinces, Kanchana Buri, Ratcha Buri, and Suphan Buri, located in west-central Thailand. Factors used for the vulnerability assessment included soil texture, slope, land use, well depth, and rainfall. These vulnerability factors were reclassified to a common scale, and a weighted average was computed to yield a vulnerability score. Vulnerability factors and weights were assigned considering pesticide concentrations in 90 wells throughout the study area. Well depth was the most significant vulnerability factor. Groundwater vulnerability maps were generated for several pesticides. The eastern, agricultural part of the study area has relatively deep wells and fine soils. Shallow wells are present in the mountainous west; however, fewer pesticides are applied in that region. Consequently, much of the study area had a medium groundwater vulnerability rating, although there were pockets of high vulnerability, for example, in agricultural areas with shallow wells. The groundwater vulnerability maps are effective for identifying locations warranting more detailed groundwater pollution and vulnerability investigations.     

A COMPARISON OF STATISTICAL TESTS ON THE EXTREME-VALUE TYPE-1 DISTRIBUTION1

ABSTRACT: The effects of the selections of plotting position formulae and class division schemes on goodness of fit tests are investigated for the extreme-value type-1 distribution using annual flood and annual maximum daily rainfall data. It was found that the plotting position formulae have a minor influence on the tests which involve their use, while the class division schemes may have a pronounced effect on the X²-test. The study also recommended the maximum likelihood method for fitting purposes and a new test which is independent of the afore-mentioned selections for judging the goodness of fit.     

"The little squealer" or "the virtual guardian angel"? Young drivers' and their parents' perspective on using a driver monitoring technology and its implications for parent-young driver communication

Introduction

In-vehicle driving monitoring technologies have the potential to enable young drivers to learn from self-assessment. However, their use is largely dependent on parental involvement.

Method

A total of 79 interviews were conducted with young drivers and parents regarding this technology and its use. Most had the experience of having an in-vehicle data recorder installed in the vehicle driven by the young drivers. Parents and the young drivers expressed both appreciation as well as reservations about its potential as a means to enhance the driving safety of young drivers.

Results

A surprising finding was that some parents did not check the feedback and said they relied on the young driver to do so. Main concerns related to privacy, parent-young driver relationship, self-esteem and confidence, constructive use of the feedback data, and the limitations of the documentation that can be done by the technology.

Conclusions

Providing parents and young drivers with a support system and tools to discuss and utilize the feedback are underscored. Challenges include addressing the invasion of young drivers’ privacy and gender differences, and using the monitoring-capacity of the technology to enhance safe driving practices. Implications for programs to enhance communication and a dialogical approach between parents and young drivers are discussed.     

Testing safety commitment in organizations through interpretations of safety artifacts

Problem

Safety culture relates to injuries and safety incidents in organizations, but is difficult to asses and measure. We describe a preliminary test of assessing an organization's safety culture by examining employee interpretations of organizational safety artifacts (safety signs).

Method

We collected data in three organizations using a new safety culture assessment tool that we label the Safety Artifact Interpretation (SAI) scale; we then crossed these data with safety climate and leadership evaluations.

Results

SAI were interpreted by employees in accordance with two conceptually distinct themes that are salient in the literature on organizational safety culture: safety compliance and commitment to safety. A significant correlation exists between SAI scores and the organizational safety climate. A similar (though insignificant) relationship was observed between SAI scores and leadership ratings.

Impact on industry

Employee perceptions and interpretations of safety artifacts can facilitate assessments of safety culture and can ultimately lead to understanding of and improvements in the level of organizational safety.     

Employee attitudes toward working with computers

This paper presents a theoretical analysis and empirical observations about the correlates of employees' attitudes toward working with computers. A measure of attitudes toward working with computers was developed and tested on a sample of 284 white collar employee from three manufacturing organizations. The expected structure of 'positive' attitudes and 'negative' attitudes (concerns) about working with computers was confirmed. Following a review of the related literature five hypotheses were proposed. Use of computers and job involvement were predicted to be positively related to attitudes toward computers. And levels of job involvement were expected to moderate the relationship between usage of computers on the job and attitudes toward computers. Both hypotheses were confirmed, although different dynamics were observed with positive attitudes than with concerns. It was found that employees who use a computer to support their work hold more positive attitudes than employees who report very limited use of the computer. And employees who are highly involved in their jobs, or committed to their organization typically reported lesser concern about working with computers than employees at a low level of job involvement. Moreover, a significant interaction was observed between job involvement and usage of computers in their relationship to attitudes toward working with computers. Further directions for research and theory development are suggested.     

Sex pheromone component ratios and mating isolation among three Lygus plant bug species of North America

The plant bugs Lygus hesperus, Lygus lineolaris, and Lygus elisus (Hemiptera: Miridae) are major pests of many agricultural crops in North America. Previous studies suggested that females release a sex pheromone attractive to males. Other studies showed that males and females contain microgram amounts of (E)-4-oxo-2-hexenal, hexyl butyrate, and (E)-2-hexenyl butyrate that are emitted as a defense against predators. Using gas chromatography–mass spectrometry, we found that female L. lineolaris and L. elisus have a 4:10 ratio of hexyl butyrate to (E)-2-hexenyl butyrate that is reversed from the 10:1 ratio in female L. hesperus (males of the three species have ~10:1 ratio). These reversed ratios among females of the species suggest a behavioral role. Because both sexes have nearly equal amounts of the major volatiles, females should release more to attract males. This expectation was supported because L. hesperus females released more hexyl butyrate (mean of 86 ng/h) during the night (1800–0700 hours) than did males (<1 ng/h). We used slow-rotating pairs of traps to test the attraction of species to blends of the volatiles with a subtractive method to detect synergism. Each species’ major butyrate ester was released at 3 μg/h, the minor butyrate according to its ratio, and (E)-4-oxo-2-hexenal at 2 μg/h. The resulting catches of only Lygus males suggest that (E)-4-oxo-2-hexenal is an essential sex pheromone component for all three species, (E)-2-hexenyl butyrate is essential for L. elisus and L. lineolaris, and hexyl butyrate is essential for L. hesperus. However, all three components are recognized by each species since ratios of the butyrate esters are critical for conspecific attraction and heterospecific avoidance by males and thus play a role in reproductive isolation among the three species. Because L. hesperus males and females are known to emit these major volatiles for repelling ant predators, our study links defensive allomones in Lygus bugs with an additional use as sex pheromones.     

Male behaviors reveal multiple pherotypes within vine mealybug Planococcus ficus (Signoret) (Hemiptera; Pseudococcidae) populations

The vine mealybug (VM) females collected in Israel produce two sex pheromone compounds: lavandulyl senecioate (LS) and (S)-lavandulyl isovalerate (LI). The males display ambiguous behavior to LI: repulsion in the vineyard and attraction of laboratory-reared males. We addressed the question of individual male behavior, i.e., do males respond to both LS and LI, or might they display a distinct response to each of the two pheromone compounds. We compared male pherotype frequencies between wild-caught and laboratory-reared populations. Then, we examined the relationship between pherotype composition and male capture rates in pheromone traps. Finally, we addressed the heredity of the pherotypes. The Israeli VM populations contain nine different male pherotypes, as defined according to the male behavior to pheromone compounds. The studied Portuguese populations included five of the nine pherotypes; none of the Portuguese males were attracted to LI. It seems that the high frequency of males that were attracted to LI is related to dense VM populations. It is hypothesized that selection for the male pherotypes, I males, those that respond to LI, occur under high-density rearing conditions. This may result from shorter development times of males and females that produce more I male pherotypes. The lower relative frequency of trapping of males in LI-baited traps than expected from the percentage determined in a Petri dish arena suggests that males that respond solely to LS (S males) are better fliers. The results also suggest that the pherotype trait is inherited by both sexes of the VM.