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.

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.

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.

Equilibrium dynamics in a model of growth and spatial agglomeration

2021 ◽  
pp. 1-26
Author(s):  
Shota Fujishima ◽  
Daisuke Oyama
Keyword(s):  
Economic Activity ◽  
Capital Accumulation ◽  
Time Preference ◽  
Stable Equilibrium ◽  
Spillover Effects ◽  
Spatial Equilibrium ◽  
Stable Equilibrium State ◽  
Macroeconomic Variables ◽  
Equilibrium Dynamics ◽  
Endogenous Growth Model

Abstract We present a multiregional endogenous growth model in which forward-looking agents choose their regions to live in, in addition to consumption and capital accumulation paths. The spatial distribution of economic activity is determined by the interplay between production spillover effects and urban congestion effects. We characterize the global stability of the spatial equilibrium states in terms of economic primitives such as agents’ time preference and intra- and interregional spillovers. We also study how macroeconomic variables at the stable equilibrium state behave according to the structure of the spillover network.

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.

Occurrence of late-emerging populations of the blueberry maggot fly (Diptera: Tephritidae)

2001 ◽  
Vol 133 (2) ◽  
pp. 239-250 ◽  
Author(s):  
L.A.F. Teixeira ◽  
S. Polavarapu
Keyword(s):  
Sibling Species ◽  
Vaccinium Corymbosum ◽  
Limiting Factor ◽  
Flight Period ◽  
Premating Isolation ◽  
Evolutionary Mechanisms ◽  
Emergence Patterns ◽  
Rhagoletis Mendax ◽  
Blueberry Maggot Fly ◽  
Commercial Field

AbstractMonitoring of adult flight patterns of the blueberry maggot fly, Rhagoletis mendax Curran, in New Jersey, indicated that the adults are active over a much longer period than previously reported. Captures on Pherocon AM traps over two seasons in wild sites and commercial fields of highbush blueberry, Vaccinium corymbosum L. (Ericaceae), showed that adult flies are present for most of the period from early July to early November. Trap captures in wild sites peaked during July–August, whereas in some commercial fields, peak captures were recorded in September. Emergence patterns were determined by collecting pupae from a wild site and a commercial field at the time of peak fruit infestation. The following year, the wild-site and commercial-field populations showed distinct emergence periods that were in broad agreement with trap captures at these locations. Comparison of an allozyme locus, using individuals collected in commercial blueberry fields, both on Pherocon AM traps and from infested fruit, confirmed that these populations were R. mendax and not any of the sibling species with a similar flight period. These data show that there are considerable phenological differences between some R. mendax populations. Given this plasticity, current debates on evolutionary mechanisms in flies of the genus Rhagoletis Loew should consider that the flight period of R. mendax is probably neither a major limiting factor in the use of hosts with different fruiting schedules nor an effective premating isolation mechanism with respect to other sibling species.

scholarly journals Growth, death, and resource competition in sessile organisms

2021 ◽  
Vol 118 (15) ◽  
pp. e2020424118
Author(s):  
Edward D. Lee ◽  
Christopher P. Kempes ◽  
Geoffrey B. West
Keyword(s):  
Evolutionary Dynamics ◽  
Resource Competition ◽  
Temporal Dynamics ◽  
Population Level ◽  
Individual Growth ◽  
Local Competition ◽  
Large Colony ◽  
Rates Of Growth ◽  
Sessile Organisms

Population-level scaling in ecological systems arises from individual growth and death with competitive constraints. We build on a minimal dynamical model of metabolic growth where the tension between individual growth and mortality determines population size distribution. We then separately include resource competition based on shared capture area. By varying rates of growth, death, and competitive attrition, we connect regular and random spatial patterns across sessile organisms from forests to ants, termites, and fairy circles. Then, we consider transient temporal dynamics in the context of asymmetric competition, such as canopy shading or large colony dominance, whose effects primarily weaken the smaller of two competitors. When such competition couples slow timescales of growth to fast competitive death, it generates population shocks and demographic oscillations similar to those observed in forest data. Our minimal quantitative theory unifies spatiotemporal patterns across sessile organisms through local competition mediated by the laws of metabolic growth, which in turn, are the result of long-term evolutionary dynamics.

scholarly journals Impact of Insecticides on Trichogramma Chilonis Parasitism and in the Oviposition Pattern of Large Cabbage Moth Eggs

2017 ◽  
Vol 20 (2) ◽  
pp. 40-43 ◽  
Author(s):  
Sateki Fangupo ◽  
Rashmi Kant ◽  
Manuel K. Palomar ◽  
Michael J. Furlong
Keyword(s):  
Lower Surface ◽  
Field Trials ◽  
Negative Effects ◽  
Parasitism Rate ◽  
Trichogramma Chilonis ◽  
Egg Masses ◽  
Insecticide Application ◽  
Parasitism Rates ◽  
Cabbage Moth ◽  
Insecticide Sprays

AbstractThis study determined the effects of key insecticides onTrichogramma chilonisparasitism in field trials. It showed that the number of large cabbage moth (LCM) eggs in Chinese cabbage was significantly reduced after application of AttackTM(p: 0.001) and EntrustTM (p: 0.00) but not after spraying with OrtheneTM (p: 0.09) and DipelTM (p: 0.485). Negative effects of insecticides were observed on the parasitism rate ofT. chilonisand LCM egg masses, which were more likely to be only partially parasitised after an insecticide application. AttackTMand EntrustTM adversely affectedT. chilonisparasitism rates of LCM eggs. However, the effect of OrtheneTM and DipelTMdid not significantly differ from each other and could be safer to the parasitoid since both reducedT. chilonisparasitism the least. The distribution of LCM eggs in the cabbage leaves was also affected by the insecticides; before insecticide application the majority of egg masses were concentrated in the upper surface of the foliage but after insecticide sprays most of the egg masses were found in the lower surface of the foliage. This study suggests that OrtheneTM and DipelTMhave no effect on the parasitism but DipelTM was found safer to the parasitoid and it could be considered for inclusion in IPM programmes that depend onT. chilonisparasitism of LCM.

Response of blueberry maggot fly (Diptera: Tephritidae) to imidacloprid-treated spheres and selected insecticides

2003 ◽  
Vol 135 (3) ◽  
pp. 427-438 ◽  
Author(s):  
O.E. Liburd ◽  
E.M. Finn ◽  
K.L. Pettit ◽  
J.C. Wise
Keyword(s):  
Untreated Control ◽  
Laboratory Experiments ◽  
Time Lag ◽  
Field Tests ◽  
Vaccinium Corymbosum ◽  
Behavioural Activity ◽  
Rhagoletis Mendax ◽  
Attract And Kill ◽  
Highbush Blueberries ◽  
Blueberry Maggot Fly

AbstractImidacloprid-treated spheres and several classes of insecticides were evaluated in field and laboratory experiments to determine their effects on Rhagoletis mendax Curran adult behavioural activity and larval infestation in highbush blueberries, Vaccinium corymbosum L. (Ericaceae). In field tests, three treatments representing an attract-and-kill system (imidacloprid-treated spheres) and two classes of insecticides, including a naturalyte spinosad (SpinTor 2 SC) and organophosphates (Imidan®/Malathion), were evaluated against an untreated control. Significantly more blueberry maggot puparia were collected from untreated (control) plots than from other treatments evaluated. There were no significant differences in larval infestation of berries collected from plots treated with imidacloprid-treated spheres, SpinTor 2 SC, and Imidan®/Malathion. Less than 1% of the berries collected from imidacloprid-treated sphere plots and SpinTor 2 SC treated plots contained blueberry maggot larvae. In toxicity and fruit-injury studies, SpinTor 2 SC as well as additional compounds from various classes were evaluated, including a botanical [azadiractin (Ecozin 3%)], a particle film [kaolin clay (SurroundTM WP)], and three neonicotinoids [imidacloprid (Provado 1.6 F), thiocloprid (Calypso 480 SC), and thiamethoxam (PlatinumTM 2 SC and ActaraTM 25 WG)]. SpinTor 2 SC exhibited a time lag (18 h) in reducing R. mendax activity. Ecozin 3% and SurroundTM WP were ineffective in suppressing R. mendax adult activity, but numbers of larvae in SurroundTM WP treated fruit were significantly reduced. The effectiveness of neonicotinoid insecticides varied initially but resulted in equivalent levels of mortality after 48 h compared with our conventional organophosphate treatment of Guthion 50 WP. Oviposition scars on Provado 1.6 F treated plots were significantly more numerous than on plots treated with SpinTor 2 SC, Calypso 480 SC, Actara 25 WG, and Guthion 50 WP.

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