Dispersal From Overwintering Sites, Action Thresholds for Blueberry Maggot Fly (Diptera: Tephritidae), and Factors That Can Influence Variation in Predicted Fruit Infestation Levels in Maine Wild Blueberry: Part I

2019 ◽  
Vol 113 (2) ◽  
pp. 851-859 ◽  
Author(s):  
Francis A Drummond ◽  
Judith A Collins
Keyword(s):  
Field Studies ◽  
Site Quality ◽  
Physiological Status ◽  
Rhagoletis Mendax ◽  
Action Threshold ◽  
Action Thresholds ◽  
The University ◽  
Blueberry Maggot Fly ◽  
Wild Blueberry ◽  
Overwintering Site

Abstract Between 1996 and 2003 field studies were conducted in wild blueberry, Vaccinium angustifolium Aiton (Ericales: Ericaceae) to determine action thresholds for the blueberry maggot fly, Rhagoletis mendax Curran (Diptera: Tephritidae). Thresholds were based upon cumulative fly trap captures on baited Pherocon AM traps. The cumulative numbers of R. mendax flies captured over time was a significant predictor of infested fruit levels (maggots/liter blueberries). Fifty percent of the variance in fruit infestation is explained by fly captures. Based upon this relationship, the University of Maine Cooperative Extension has recommended action threshold of 10 cumulative fly captures/trap. However, this threshold is liberal in terms of risk as only 50% of the variance in fruit infestation is explained by fly captures. The dynamics of colonization rate and fly physiological status entering fruit-bearing fields might partially explain the variance in the action threshold. The majority of flies emerge from pruned fields or along forest scrub/shrub field edges, and it takes between 1 and 10 d (mean = 4.1 ± 0.9 d) for the populations to enter adjacent fruit-bearing fields. Flies dispersed from pruned fields at a decreasing rate the farther they dispersed. The rate of dispersal into fruit-bearing wild blueberry fields also depends upon the overwintering site quality. Sites with fruit exhibited both delayed colonization and lower colonization rates into fruit-bearing fields than adjacent pruned fields with no fruit. We also found that as the season progressed the proportion of flies capable of laying eggs varied greatly by location and year.

Temporal Dynamics of the Blueberry Maggot Fly (Diptera: Tephritidae) and its Primary Parasitoid, Biosteres melleus (Hymenoptera: Braconidae), in the Maine Wild Blueberry System

2019 ◽  
Vol 113 (2) ◽  
pp. 720-730 ◽  
Author(s):  
Francis A Drummond ◽  
Judith A Collins
Keyword(s):  
Predictive Model ◽  
Stable Equilibrium ◽  
Temporal Dynamics ◽  
Equilibrium Dynamics ◽  
Rhagoletis Mendax ◽  
Parasitism Rates ◽  
Blueberry Maggot Fly ◽  
Rates Of Growth ◽  
Wild Blueberry ◽  
Insecticide Sprays

Abstract Between 1998 and 2017, we conducted studies in wild blueberry, Vaccinium angustifolium Aiton (Ericales: Ericaceae), to elucidate the temporal dynamics of the blueberry maggot fly, Rhagoletis mendax Curran, and its parasitoid, Biosteres melleus (Gahan). A predictive model for the emergence of R. mendax was validated at two sites over 3 yr. A second predictive model for the major parasitoid, B. melleus, of R. mendax was constructed and suggests that the delay in emergence of the parasitoid relative to its host provides a period or ‘biological window’ of 9 d where insecticide sprays can be applied to manage R. mendax with a limited impact on the parasitoid. A 20-yr study on the parasitoid/host dynamics showed parasitism rates ranging from 0.5 to 28.2%. It appears that R. mendax populations in Maine wild blueberry are characterized by stable equilibrium dynamics, significantly affected by stochastic processes. There was a weak, but significant relationship between B. melleus density and R. mendax intrinsic rates of growth. Our data suggest that R. mendax population dynamics in wild blueberry is characterized by an unstable equilibrium tipping point of 7.9 maggots per liter of blueberries or an average of 10 flies per trap.

scholarly journals Population Dynamics of Spotted Wing Drosophila (Drosophila suzukii Matsumara) in Maine Wild Blueberry (Vaccinium angustifolium Aiton)

2019 ◽  
Author(s):  
Francis Drummond ◽  
Elissa Ballamn ◽  
Judith Collins
Keyword(s):  
Relative Abundance ◽  
Predation Rate ◽  
Drosophila Suzukii ◽  
Insecticide Application ◽  
Wild Fruit ◽  
Air Temperatures ◽  
Action Threshold ◽  
Gamma Density ◽  
Action Thresholds ◽  
Wild Blueberry

A long-term investigation of D. suzukii dynamics in wild blueberry fields from 2012 - 2018 demonstrates relative abundance is still increasing seven years after initial invasion. Relative abundance is determined by physiological date of first detection and air temperatures the previous winter. Date of first detection of flies does not determine date of fruit infestation. The level of fruit infestation is determined by year, fly pressure, and insecticide application frequency. Frequency of insecticide application is determined by production system. Non-crop wild fruit and predation influences fly pressure; increased wild fruit abundance results in increased fly pressure. Increased predation rate reduces fly pressure, but only at high abundance of flies, or when high levels of wild fruit are present along field edges. Male sex ratio might be declining over the seven years. Action thresholds were developed from samples of 92 fields from 2012 - 2017 that related cumulative adult male trap capture to the following week likelihood of fruit infestation. A two-parameter gamma density function describing this probability was used to develop a risk-based gradient action threshold system. The action thresholds were validated from 2016-2018 in 35 fields and were shown to work well in two of three years (2016 and 2017).

Field Perimeter Trapping to Manage Rhagoletis mendax (Diptera: Tephritidae) in Wild Blueberry

2020 ◽  
Vol 113 (5) ◽  
pp. 2380-2389
Author(s):  
Francis A Drummond ◽  
Judith A Collins
Keyword(s):  
Computer Simulation Model ◽  
Double Row ◽  
Vaccinium Angustifolium ◽  
Agent Based ◽  
Single Row ◽  
Rhagoletis Mendax ◽  
Major Pest ◽  
Blueberry Maggot Fly ◽  
Wild Blueberry ◽  
Trap Placement

Abstract Rhagoletis mendax Curran (the blueberry maggot fly) is a major pest of wild blueberry. It is a direct pest of the fruit. Females lay eggs in fruit resulting in infestations of larvae unacceptable to most consumers. Three field perimeter interception tactics were tested for control of R. mendax in wild blueberry, Vaccinium angustifolium Aiton (Ericales: Ericaceae), between 2000 and 2010. We investigated field perimeter deployment of baited, insecticide-treated, green spheres (2000–2005), baited, yellow Trécé PHEROCON AM traps (2005 and 2006), and baited, Hopper Finder, sticky barrier tape (2008–2010). Only the Hopper Finder tape provided significant reduction in R. mendax adults and fruit infestation over the 3-yr field study. However, the reduction in fruit infestation compared with control plots was only 48.2 ± 7.3%, a level of reduction in damage that would be unsuitable for many commercial wild blueberry growers as a stand-alone tactic, but could be an important reduction as part of a multiple tactic IPM strategy. In addition, we constructed an agent-based computer simulation model to assess optimal trap placement between three patterns: 1) a single row of traps along field perimeter; 2) a double row of traps along the field perimeter at half the density of the single row; and 3) a grid of traps spread throughout the field but with the largest distance between traps. We found that the single row deployment pattern of traps was the best for reducing immigration of R. mendax adults into simulated fields.

scholarly journals Population Dynamics of Spotted Wing Drosophila (Drosophila suzukii (Matsumura)) in Maine Wild Blueberry (Vaccinium angustifolium Aiton)

Insects ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 205 ◽  
Author(s):  
Francis Drummond ◽  
Elissa Ballman ◽  
Judith Collins
Keyword(s):  
Relative Abundance ◽  
Predation Rate ◽  
Drosophila Suzukii ◽  
Insecticide Application ◽  
Wild Fruit ◽  
Air Temperatures ◽  
Action Threshold ◽  
Gamma Density ◽  
Action Thresholds ◽  
Wild Blueberry

A long-term investigation of D. suzukii dynamics in wild blueberry fields from 2012–2018 demonstrates relative abundance is either still increasing or exhibiting periodicity seven years after the initial invasion. Relative abundance is determined by physiological date of first detection and air temperatures the previous winter. Date of first detection of flies does not determine date of fruit infestation. The level of fruit infestation is determined by year, fly pressure, and insecticide application frequency. Frequency of insecticide application is determined by production system. Non-crop wild fruit and predation influences fly pressure; increased wild fruit abundance results in increased fly pressure. Increased predation rate reduces fly pressure, but only at high abundance of flies, or when high levels of wild fruit are present along field edges. Male sex ratio might be declining over the seven years. Action thresholds were developed from samples of 92 fields from 2012–2017 that related cumulative adult male trap capture to the following week likelihood of fruit infestation. A two-parameter gamma density function describing this probability was used to develop a risk-based gradient action threshold system. The action thresholds were validated from 2016–2018 in 35 fields and were shown to work well in two of three years (2016 and 2017).

Drawing to Tell Versus Drawing to Intrigue?

2021 ◽  
Vol 55 (3) ◽  
Author(s):  
Michael Renner
Keyword(s):  
Cultural Influences ◽  
Field Studies ◽  
Visual Anthropology ◽  
Indigenous Culture ◽  
University Of Cambridge ◽  
Blackwater Fever ◽  
Starting Point ◽  
New Hebrides ◽  
The University ◽  
Intention To Continue

The article “Drawing It Out” by Haidy Geismar (2014) in Visual Anthropology Review (Vol. 30, No. 2, pp. 97–113) focused on the use of images in early anthropology. The drawings by Arthur Bernard Deacon (1903–1927), which he made during his field studies in Vanuatu, New Hebrides from 1926 until his sudden death caused by blackwater fever in 1927, are the starting point of Geismar’s inquiry. The author discusses Deacon’s drawings and infers the potential of drawing as a methodology for anthropology. Deacon was a young PhD candidate who was sent to Vanuatu from the University of Cambridge. It was his intention to continue the studies of the indigenous culture of the New Hebrides at the time, which had been started by the Department of Anthropology at the University of Cambridge. In contrast to his expectations, Deacon found a culture in the process of decay. The subject of his study, the indigenous culture, had been threatened by diseases and cultural influences that settlers, missionaries, and traders imported with them since they landed in the middle of the nineteenth century. Deacon described the impossibility of protecting the indigenous culture and critically reflected on his role as an anthropologist (Geismar 2014, p. 102).

scholarly journals Mushrooms of Grand Teton National Park

1983 ◽  
Vol 7 ◽  
pp. 59-71
Author(s):  
Kent McKnight ◽  
Kimball Harper ◽  
Karl McKnight
Keyword(s):  
National Parks ◽  
Vascular Plants ◽  
National Park ◽  
Annual Report ◽  
Plant Cover ◽  
Field Studies ◽  
Soil Samples ◽  
Site Quality ◽  
Soil Parameters ◽  
Quantitative Estimates

The primary overall objective of inventorying the macrofungi growing in and around Grand Teton and Yellowstone National Parks was partially achieved with the published checklist (McKnight 1982) and additions from the 1982 Research Center Annual Report (McKnight, Harper, & McKnight 1984). The intensive collecting of the 1982 fruiting season including a 12-week phenological study at 11 selected sites left many species unidentified and numerous others observed but not collected, or with inadequately annotated collections made. Litter and soil moisture data for the 11 study stands are also given in the 1982 annual report cited above, as well as data on 15 overstory and understory vegetation and soil parameters. Field studies in the Parks during the summer of 1983 concentrated on (1) identification of chlorophyllous and vascular plants at the 11 sites selected for concentrated study in 1982; (2) quantitative estimates of chlorophyllous plant cover and height; (3) estimates of site quality; (4) collections of composite soil samples; and (5) additional records of macrofungi for the Parks with supporting data in the form of photographs, drawings, and annotations.

scholarly journals Three short studies from field studies in marine biology and oceanography

SURG Journal ◽  
2013 ◽  
Vol 6 (2) ◽  
pp. 78-92
Author(s):  
Melanie Barry ◽  
Shannon Ferraro ◽  
Kaitlyn Wagner
Keyword(s):  
New Brunswick ◽  
Benthic Invertebrates ◽  
Marine Mammals ◽  
Marine Biology ◽  
State Of The Art ◽  
Field Studies ◽  
Integrative Biology ◽  
Research Projects ◽  
Science Centre ◽  
The University

ZOO*4300 (Marine Biology and Oceanography) is a senior-level field course offered by the Department of Integrative Biology at the University of Guelph. This two-week course is held at the Huntsman Marine Science Centre in St. Andrew’s New Brunswick, Canada. Students enrolled in the course study various aspects of the ecology, behaviour, physiology, biochemistry and genetics of marine organisms using a variety of oceanographic techniques. The course also includes group exercises to study various intertidal and sub-tidal environments as well as boat cruises to collect plankton, benthic invertebrates, marine fish, and to observe marine mammals. The course provides excellent opportunities for students to familiarize themselves with state-of-the-art techniques involved in various branches of marine biology and oceanography and conduct an individual research project. This feature highlights three individual research projects by University of Guelph students. More information about the field course in marine biology and oceanography is accessible at the following link: http://www.uoguelph.ca/ib/undergrad/fieldcourses_marine.shtml.

Sampling Techniques and Setting Thresholds

2020 ◽  
pp. 381-398
Author(s):  
Patricia J. Vittum
Keyword(s):  
Sampling Techniques ◽  
Insect Management ◽  
Site Specific ◽  
Tolerance Level ◽  
Management Regime ◽  
Action Threshold ◽  
Insect Populations ◽  
Action Thresholds ◽  
Inspection Techniques ◽  
Standard Techniques

This chapter looks at sampling techniques and setting thresholds. The cornerstone of any integrated insect management regime is accurately identifying pest insects (including assessing population density) and developing appropriate action thresholds. Various methods have evolved by which the populations of insects present in the turf environment may be determined relatively rapidly and efficiently. These methods have become standard techniques for reporting insect densities. The chapter differentiates between passive sampling techniques (use of traps) and active visual inspection techniques (actual quantification of insect populations). Thresholds in turf integrated pest management usually are more accurately considered tolerance levels, or action thresholds. The tolerance level, or action threshold, for turfgrass insects is site-specific and depends on many factors.

Movement of Rhagoletis mendax (Diptera: Tephritidae) in Fruit-Bearing Wild Blueberry Fields. Part II

2020 ◽  
Vol 113 (3) ◽  
pp. 1323-1336
Author(s):  
Francis A Drummond ◽  
Judith A Collins ◽  
Sara L Bushmann
Keyword(s):  
Colonization Rate ◽  
Crop Canopy ◽  
Movement Rate ◽  
Highly Active ◽  
Rhagoletis Mendax ◽  
Field Edge ◽  
Growth Chambers ◽  
Temporal And Spatial ◽  
Low Altitude ◽  
Wild Blueberry

Abstract During dispersal into fruit-bearing wild blueberry fields, blueberry maggot flies were highly active during all daylight hours as revealed by trap captures, although in one trial afternoon activity was greater than morning activity. Flies were not captured in traps at night, although observations in growth chambers showed that their activity at night, measured as displacement of position, was equal to daylight conditions. Flies were shown to fly at low altitude, just above the crop canopy, and screen fencing was shown to be effective at reducing colonization of plots, presumably due to their low height during flight. Over a 4-yr mark–capture study, colonization rate was shown to be low at 9.7 m/d, although a separate 2010 study showed higher rates at 14.1 and 28.0 m/d. Movement was shown to be nondirectional or random in the field, but a constrained random walk exhibiting direction into the field. Weed cover and high fruit density were associated with higher fly relative abundance, suggesting these field characteristics served as attractors slowing colonization rate into a field. Transect trap studies showed the temporal and spatial pattern of fly colonization into commercial wild blueberry fields, one of a slow wave that penetrates into the field interior as the season progresses. There is also an increase in fly abundance within-field edges and adjacent forest. The ‘stacking’ of flies along a field edge and slow movement rate into a field was shown through simulation to be a result of nondirectional short-distance dispersal of flies.

AN EVALUATION OF SEVERAL METHODS OF ESTIMATING SITE INDEX OF IMMATURE STANDS

1952 ◽  
Vol 28 (3) ◽  
pp. 63-74 ◽  
Author(s):  
John W. Ker
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Site Quality ◽  
Average Height ◽  
Office Procedure ◽  
Minimum Sample ◽  
A Site ◽  
The University ◽  
Site Classes

The use of dominant heights for the estimation of site index is compared with the use of the average of dominant and codominant heights. Data collected on the University Research Forest are presented to illustrate the variability in tree heights and diameters within the two upper crown classes in well-stocked stands of immature Douglas fir.HeightIt is shown that the use of dominant heights reduces considerably the number of measurements required for a site index determination of given accuracy. Minimum sample sizes are given for three limits of accuracy for use in different site qualities. A general field and office procedure is outlined for the determination of minimum sample size in stands other than those described.DiameterThe use of diameter in site determination is discussed. Site indices based on the height of the tree of mean diameter, the height of the tree of mean basal area, and mean height are compared.ConclusionsQuick estimates of site quality can best be obtained by the measurement of total height of sample dominant trees, selected at random. For this purpose, tables are presented which list the average height of dominant trees by age and site classes for use in stands of Douglas fir, and western hemlock, respectively.

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