Effects of squash leaf trichome exudates and honey on adult feeding, survival, and fecundity of the squash bug (Heteroptera: Coreidae) egg parasitoid Gryon pennsylvanicum (Hymenoptera: Scelionidae)

Citation: Olson, D., & Nechols, J. Effects of Squash Leaf Trichome Exudates and Honey on Adult Feeding, Survival, and Fecundity of the Squash Bug (Heteroptera: Coreidae) Egg Parasitoid Gryon pennsylvanicum (Hymenoptera: Scelionidae). Environmental Entomology, 24(2), 454-458. https://doi.org/10.1093/ee/24.2.454A laboratory experiment was conducted to determine whether leaf exudates could be used as a source of adult nutrition for the squash bug, Auasa tristis (De Geer), egg parasitoid, Gryon pennsylvanicum (Ashmead), and to compare adult and progeny fitness traits when female Wasps were provided with squash leaves, a standard honey diet, a combination of leaves and honey, or water only Results showed that fecundity, progeny developmental rates, and progeny survival did not differ significantly when females were exposed to different dietary sources. Adult longevity was shorter on squash leaves without honey than on leaves with honey or the honey-only diet. However, reproductive fitness was not reduced because oviposition had been completed before death of the adult females. When only water was provided, parasitoid females lived only a few days. Observations showed that squash leaves have two kinds of trichomes (hair-like and peg-like), both of which produce droplets that are fed on by both sexes of G. pennsylvanicum. Nutrient analyses revealed that exudates from the hair-like trichomes are composed predominantly of monosaccharides (mainly glucose and galactose), and that the peg-like trichomes produce glucose and some protein. Thus, these trichomes appear to serve as extrafloral nectaries and may provide an important energy source for augmentatively released G. pennsylvanicum

PON1 status does not influence cholinesterase activity in Egyptian agricultural workers exposed to chlorpyrifos.

Animal studies have shown that paraoxonase 1 (PON1) genotype can influence susceptibility to the organophosphorus pesticide chlorpyrifos (CPF). However, Monte Carlo analysis suggests that PON1 genotype may not affect CPF-related toxicity at low exposure conditions in humans. The current study sought to determine the influence of PON1 genotype on the activity of blood cholinesterase as well as the effect of CPF exposure on serum PON1 in workers occupationally exposed to CPF. Saliva, blood and urine were collected from agricultural workers (n=120) from Egypt's Menoufia Governorate to determine PON1 genotype, blood cholinesterase activity, serum PON1 activity towards chlorpyrifos-oxon (CPOase) and paraoxon (POase), and urinary levels of the CPF metabolite 3,5,6-trichloro-2-pyridinol (TCPy). The PON1 55 (P≤0.05) but not the PON1 192 genotype had a significant effect on CPOase activity. However, both the PON1 55 (P≤0.05) and PON1 192 (P≤0.001) genotypes had a significant effect on POase activity. Workers had significantly inhibited AChE and BuChE after CPF application; however, neither CPOase activity nor POase activity was associated with ChE depression when adjusted for CPF exposure (as determined by urinary TCPy levels) and stratified by PON1 genotype. CPOase and POase activity were also generally unaffected by CPF exposure although there were alterations in activity within specific genotype groups. Together, these results suggest that workers retained the capacity to detoxify chlorpyrifos-oxon under the exposure conditions experienced by this study population regardless of PON1 genotype and activity and that effects of CPF exposure on PON1 activity are minimal

The Uniformity Factor-a Proposed Method for Expressing Variations in Specific Gravity

Existing measures of uniformity of specific gravity, as obtained by X-ray densitometry, are examined in light of how well they fulfill the requirements thought to be necessary for a uniformity indicator. Based upon an examination of mass and volume specific gravity distributions, a new indicator is proposed. This indicator, the uniformity factor, relates the volume distribution of specific gravity within an increment of wood to a selected reference base. The suitability of the uniformity factor for estimating wood uniformity is shown using data from two species of different uniformities. This approach appears to have potential as a new tool in predicting wood quality

Wood Property Variation Among Forty-Eight Families of American Sycamore

American sycamore (Platanus occidentalis L.) progeny from forty-eight half-sib families representing five geographic seed sources were analyzed at the end of the fifth growing season for variation in wood properties and growth rate. Stem analysis revealed that specific gravity increased towards the top of the tree while fiber length first increased and then decreased as a function of height within the stem. Diameter, height, volume, specific gravity, fiber length, and moisture content showed significant differences between families. Height and moisture content were the only traits that did not exhibit significant variation due to seed source. Wood properties exhibited considerably less variation than did the growth parameters. However, wood properties did exhibit a larger component of variance due to family effects than did the growth parameters. Diameter, height, and volume were positively correlated with specific gravity and fiber length

Specific Gravity, Fiber Length, and Extractive Content of Young Paulownia

The potential of using paulownia (Paulownia tomentosa) as a pulpwood species was assessed by evaluating the within-tree variation in specific gravity, fiber length, and extractive content of young trees growing on surface-mined land. Stem-wood fiber length and extractive-free specific gravity averaged 0.79 mm and 0.249, respectively. Total average extractive content approached 13%. Compared with other fast-growing hardwoods, paulownia has a lower specific gravity, shorter fiber length, and higher extractive content. All of these factors make paulownia a poor pulpwood species for most types of paper. Its fast growth rate may, however, favor the species as a valuable fiber source for some specialty-type papers where strength is not important

MICROCOMPUTER BUDGET MANAGEMENT SYSTEM

The enterprise budget, whole farm cash flow, and income statement are fundamental tools of farm and ranch management. The "Microcomputer Budget Management System" (MBMS) is a microcomputer software package that facilitates the storage and use of information for crop and livestock budgeting. It performs the calculations for several enterprise budgeting formats and for preparation of whole farm resource use reports and financial statements. The MBMS also includes internal machinery and irrigation cost calculation routines. MBMS was developed for use by extension staff, researchers, lenders, consultants, and operators of diversified farms and ranches with many enterprises that use enterprise and whole farm budgeting for analysis and planning activities. The flexibility and detailed nature of the program requires the user to have knowledge of enterprise budgeting and operation of complex computer programs. This paper presents a discussion of the features and capabilities of the software and the computational procedures used in the cost calculations.Research and Development/Tech Change/Emerging Technologies,

North Dakota Crop Production Economics in 1991

Production Economics,

Magnitude of behavioral deficits varies with job-related chlorpyrifos exposure levels among Egyptian pesticide workers.

Chronic occupational exposure to organophosphorus pesticides (OPs) is consistently associated with deficits on behavioral tests when compared to unexposed comparison groups. However, a dose-response relationship has yet to be established, leading some to doubt an association between occupational OP exposure and behavioral deficits. Pesticide application teams in Egypt who are primarily exposed to one OP, chlorpyrifos (CPF), were recruited into a field assessment. Trail Making A and the more challenging Trail Making B tests were administered to 54 engineers (who supervise the pesticide application process, usually from the side of the field), 59 technicians (who guide the pesticide applicators in the field), 31 applicators (who mix and apply pesticides using knapsack sprayers), and 150 controls (who did not work in the fields) at two different times during the OP application season as well as immediately after applications had ended and 1.5 months later. All participants were males since only males work on pesticide application teams in Egypt. Urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy), a specific metabolite of CPF, confirmed the pattern of lower to higher CPF exposures from engineers to technicians to applicators, and these were all greater than urinary metabolite levels in controls. A consistent relationship between job title and performance speed on the behavioral task was observed: Controls had the best (fastest) performance on Trail Making A and B tests throughout the application season, and applicators had significantly slower performance than engineers on Trail Making A (p = 0.015) and B (p = 0.003). However, individual urinary TCPy, blood acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) levels did not predict individual performance. This study identifies a dose-related effect based on job title, which serves as a surrogate for chronic exposure in that differing job titles exhibit varying group exposure levels. The results establish that chronic occupational exposure to chlorpyrifos is neurotoxic and suggest that the classic biomarkers of recent CPF exposure are not predictive of chronic exposure effects