THE SPATIAL DISTRIBUTION OF SPRING AND SUMMER POPULATIONS OF ADULT POTATO FLEA BEETLES, EPITRIX CUCUMERIS (HARRIS) (COLEOPTERA: CHRYSOMELIDAE), ON SMALL PLOTS OF POTATOES

1989 ◽  
Vol 121 (12) ◽  
pp. 1097-1101 ◽  
Author(s):  
Jeff G. Stewart ◽  
Leith S. Thompson
Keyword(s):  
Spatial Distribution ◽  
Flea Beetle ◽  
Regression Equations ◽  
Flea Beetles ◽  
Mean Crowding ◽  
The Mean ◽  
Potato Flea Beetle

AbstractThe spatial distribution of spring and summer populations of the potato flea beetle, Epitrix cucumeris (Harris) (Coleoptera: Chrysomelidae), on potatoes (“Superior” variety) was studied in 1987 and 1988. Slopes of the regression of mean crowding on the mean number of adults per plant were not significantly different from 1.0 except for summer populations in 1988. The y-intercepts of these regression equations were not significantly different from 0, suggesting that adults of the potato flea beetle are not aggregated. The ratios of mean crowding to mean number of adults per plant were 0.81 for spring populations and 1.02 for summer populations, also indicating that the populations were not highly aggregated. With a level of precision of 0.25, 10 samples per plot were appropriate when more than 2.8 adults per plant were present in the spring and when more than 7.2 adults per plant were present in the summer.

PATTERNS OF FEEDING INJURY TO POTATO BY THE POTATO FLEA BEETLE (COLEOPTERA: CHRYSOMELIDAE) IN MANITOBA

1996 ◽  
Vol 128 (5) ◽  
pp. 791-804
Author(s):  
S.F. Pernal ◽  
D.G. Senanayake ◽  
N.J. Holliday
Keyword(s):  
Vertical Distribution ◽  
Repeated Measures ◽  
Seasonal Pattern ◽  
Flea Beetle ◽  
Control Measures ◽  
Potato Plants ◽  
Flea Beetles ◽  
The Mean ◽  
The Vertical Distribution ◽  
Potato Flea Beetle

AbstractThe amount and distribution of foliar feeding injury by adult potato flea beetles, Epitrix cucumeris (Harris), were examined on individually caged potato plants grown in field plots in Manitoba. Plants were either maintained as uninfested controls, or were exposed throughout the growing season to different insect densities that mimicked the natural seasonal pattern of infestation. In 1984, a trial was conducted using cv. ‘Norland’ exposed to four different densities of potato flea beetles. In 1989 and 1990, cv. ‘Russet Burbank’ was exposed to potato flea beetles, and in some treatments, plants were exposed to early summer infestations of Colorado potato beetles, Leptinotarsa decemlineata (Say). In each trial, during the late summer period of high potato flea beetle density, the amount and distribution of flea beetle feeding injury were assessed at weekly intervals. Counts of feeding punctures in single leaflets were made from leaves in the upper, middle, and lower third of each caged plant, and these data were subjected to repeated measures analysis of variance. In each of the 3 years, increasing the number of flea beetles increased the mean number of feeding punctures per leaflet in an approximately linear fashion; however, the number of punctures per beetle varied between cultivars and years. In 1984 and 1990, the number of feeding punctures per leaflet was least in the upper third of the plants, and greater in the lower, or middle and lower, third of plants. However, in 1989, the vertical distribution of feeding punctures was relatively even. Previous feeding by Colorado potato beetles increased the mean number of flea beetle feeding punctures per leaflet and changed the vertical distribution of feeding punctures. Rainfall and temperature were correlated with patterns of flea beetle injury; injury was concentrated on lower leaflets during weeks of greater rainfall, and upper leaflets were injured most during weeks with higher average temperatures. It is concluded that flea beetles exhibit preferences for feeding in specific portions of potato plants, and that these preferences change in response to previous defoliation and are influenced by meteorological conditions. Consequently, counting feeding punctures would not be a reliable method of assessing whether control measures for potato flea beetles are justified.

DISSEMINATION OF HOWARDULA SP. NEMATODES BY ADULT TOBACCO FLEA BEETLES (COLEOPTERA: CHRYSOMELIDAE)

1977 ◽  
Vol 109 (9) ◽  
pp. 1283-1285 ◽  
Author(s):  
Kent D. Elsey
Keyword(s):  
Adult Male ◽  
Average Rate ◽  
Flea Beetle ◽  
Nematode Parasite ◽  
Free Living ◽  
Flea Beetles ◽  
The Mean

AbstractA Howardula sp. nematode parasite of the tobacco flea beetle, Epitrix hirtipennis (Melsheimer), was able to utilize the adult male to disseminate juveniles. At 27°C the mean total number of juveniles released per beetle was 369 for female beetles and 377 for males at an average rate of ca. 37 per day from both sexes. A cooler temperature retarded the onset of dissemination but did not affect the rate of release. Fifty-nine per cent of the free-living nematodes survived for 5–6 days, but none survived beyond 13 days. Seventy-nine per cent of the free-living nematodes were female.

Spatial Simulation of Precipitation Resources in Chongqing

2012 ◽  
Vol 518-523 ◽  
pp. 4261-4265
Author(s):  
Xiao Song Lin ◽  
Sha Sha Yu ◽  
Hai Yan Wang
Keyword(s):  
Spatial Distribution ◽  
Spatial Interpolation ◽  
Regional Difference ◽  
Interpolation Method ◽  
Annual Precipitation ◽  
Regression Equations ◽  
Spatial Simulation ◽  
Simulation Data ◽  
Spatial Interpolation Method ◽  
Precise Simulation

Years’ precipitation data of Chongqing from 101 metrological stations has been adopted in the paper and the regression equations between annual precipitation and altitude, longitude, and height have been obtained by the use of SPSS, then elaborate simulation of Chongqing’s precipitation resources based on regression analysis was completed through the 1km×1km grid system and fitted equation. Elaborated simulation of precipitation resources was realized by best spatial interpolation method with the support of GIS; then the results of two different simulation methods were coupled in the form of linear combination to obtain the coupling simulation of spatial distribution of Chongqing’s precipitation resources, finally the precipitation resources were summed up and distributed according to different administration areas at county level and thus obtain precise simulation data of precipitation resources in each county of Chongqing. The results showed that there is a remarkable regional difference in the spatial distribution of precipitation resources of Chongqing, and it decreases from the southeast to the northwest in general, with the annual precipitation higher than 1270mm in southeast and lower than 1080mm in northwest.

scholarly journals Finding the pattern: online extraction of spatial structure during virtual navigation

2019 ◽  
Author(s):  
Kathryn Nicole Graves ◽  
James Antony ◽  
Nicholas Turk-Browne
Keyword(s):  
Spatial Distribution ◽  
Animal Behavior ◽  
Virtual Water ◽  
Single Session ◽  
Statistical Knowledge ◽  
Navigation Patterns ◽  
The Mean ◽  
Online Extraction ◽  
Human Participants ◽  
The Individual

While navigating the world, we pick up on patterns of where things tend to appear. According to theories of memory and studies of animal behavior, knowledge of these patterns emerges gradually over days or weeks, via consolidation of individual navigation episodes. Here we discover that navigation patterns can also be extracted online, prior to the opportunity for offline consolidation, as a result of rapid statistical learning. Human participants navigated a virtual water maze in which platform locations were drawn from a spatial distribution. Within a single session, participants increasingly navigated through the mean of the distribution. This behavior was better simulated by random walks from a model with only an explicit representation of the current mean, compared to a model with only memory for the individual platform locations. These results suggest that participants rapidly summarized the underlying spatial distribution and used this statistical knowledge to guide future navigation.

scholarly journals Generalized predictive model of estimation of inhibition of muscarinic receptors M1-M5

2020 ◽  
Vol 3 (3) ◽  
pp. e00129
Author(s):  
A.V. Mikurova ◽  
V.S. Skvortsov ◽  
V.V. Grigoryev
Keyword(s):  
Predictive Model ◽  
Muscarinic Receptors ◽  
Three Dimensional ◽  
Dynamics Simulation ◽  
Dimensional Structure ◽  
Regression Equations ◽  
Energy Characteristics ◽  
Value Prediction ◽  
M3 Receptor ◽  
The Mean

A general predictive model for assessing the inhibition constant (K<sub>i</sub>) value of human acetylcholine muscarinic receptors M1-M5 by potential ligands has been constructed. We used information on the three-dimensional structure of human M1, M2, M4, and M5 receptors, as well as a model of the M3 receptor constructed according to homology based on the structure of the rat M3 receptor. A set of complexes of known inhibitors with the target receptor constructed by means of molecular docking, was selected using an additional option: the coincidence of the spatial position of 4 pharmacophore points of a tested inhibitor and tiotropium, for which the position in the crystal structure was known. For five types of M receptors 199 complexes with known K<sub>i</sub> values were selected. Based on the data obtained during molecular dynamics simulation of these complexes by means of the MM-PBSA/MM-GBSA methods, their energy characteristics were calculated. They were used as independent variables in linear regression equations for pK<sub>i</sub> value prediction. The R<sup>2</sup> prediction for the generalized equation was 0.7, and the mean prediction error was 0.55 logarithmic units with a range for pK<sub>i</sub>=4.7.

scholarly journals Prediksi Tinggi Badan Ditentukan dari Panjang Rentang Lengan dan Panjang Telapak Kaki Pada Mongoloid Feminina Khususnya Etnis Jawa

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Nur Mujaddidah Mochtar
Keyword(s):  
Clinical Medicine ◽  
Pearson Correlation ◽  
Body Height ◽  
Regression Equation ◽  
The Body ◽  
Regression Equations ◽  
Foot Length ◽  
Arm Span ◽  
Knee Height ◽  
The Mean

Background: There are various circumstances where measurements are not actually possible, replacement parameters can be used to estimate body height. Many characteristics of body height measurement and how to measure it. These include anthropometric measurements that can be used for the identification of medicolegal-forensic processes. Body height in clinical medicine and in the field of scientific research can be easily estimated using various anthropometric parameters such as arm span, knee height, foot length and foot breadth, and others. The arm span and foot length has proved to be one of the most reliable predictors. This study was conducted to estimate of body height from arm span and foot length using the regression equation and to determine the correlation between the body height and arm span and foot length.Methods: This study was conducted at Universitas Muhammadiyah Surabaya with 182 Javanese female students. Stature, arm span and foot length measured directly using anthropometric technique and measuring tape. The data obtained were then analyzed with SPSS version 16. The regression equation was derived for the estimate of body height and the relationship between stature, arm span and foot length determined by the Pearson correlation.               Results: We found that the mean body height of Javanese women was 1534,45 ± 47,623  mm, mean of arm span 1543,25 ± 60,468 mm and the mean of foot length 226,14 ± 9,586 mm. The correlation between stature and arm span was positive and significant (r = 0,715  , p <0,05). The correlation between stature and foot length was positive and significant (r = 0,726 , p <0,05). The correlation between stature and arm span and foot length was positive and significant (r = 0,798, p <0,05).               Conclusion: Body height correlates well with the arm span and foot length so that it can be used as a reliable marker for high estimates using regression equations.

scholarly journals Pests and diseases affecting potato landraces and bred varieties grown in Peru under indigenous farming system

2016 ◽  
Vol 19 (2) ◽  
pp. 29-41
Author(s):  
W. Pérez Barrera ◽  
M. Valverde Miraval ◽  
M. Barreto Bravo ◽  
J. Andrade-Piedra ◽  
G. A. Forbes
Keyword(s):  
Flea Beetle ◽  
Farming System ◽  
Leaf Beetle ◽  
Black Scurf ◽  
Potato Seed ◽  
Potato Leaf ◽  
Pests And Diseases ◽  
Andean Potato ◽  
Seed Degeneration ◽  
Potato Flea Beetle

The major pests and diseases were identified and quantified on thirteen potato landraces and three bred varieties cultivated in Peru. Late blight (Phytophthora infestans) was the primary biotic constraint affecting plants before flowering with an average severity of 24%. No other pathogens caused severe foliar disease, but black scurf (Rhizoctonia solani) was relatively common on tubers of some genotypes with incidence ranging from 4.30 to 33.33%. The viruses most generally considered important in potato seed degeneration, PVY and PLRV, were extremely rare, with 1.11 and 0.12 % incidence, respectively. Other viruses considered mild, such as PVX and PVS, were more common, with incidence of 28.23 and 22.29 %, respectively. Potato flea beetle (Epitrix spp.), potato leaf beetle (Diabrotica spp.) and Andean potato weevil (Premnotrypes spp.) were common, with incidence of 28.14, 18.75 and 13.61%, respectively. Potato landraces known as Ishkupuru, Lengua de vaca, Chaulina, Chaulina Tajacaja and Negro cayash were identified as potentially resistant to P. infestans.

scholarly journals Quantifying the Feeding Periods Required by Corn Flea Beetles to Acquire and Transmit Pantoea stewartii

Plant Disease ◽  
2006 ◽  
Vol 90 (3) ◽  
pp. 319-324 ◽  
Author(s):  
B. Menelas ◽  
C. C. Block ◽  
P. D. Esker ◽  
F. W. Nutter
Keyword(s):  
Nalidixic Acid ◽  
Growth Models ◽  
Flea Beetle ◽  
Feeding Time ◽  
Feeding Period ◽  
Selective Media ◽  
Pantoea Stewartii ◽  
Flea Beetles ◽  
Time Required ◽  
The Relationship

The feeding periods required by corn flea beetles to acquire and transmit Pantoea stewartii were investigated in the Stewart's disease of corn pathosystem. To quantify the effect of acquisition feeding period on percentage of acquisition, field-collected corn beetles were allowed to feed for 6, 12, 24 36, 48, and 72 h on corn seedlings previously inoculated with a rifampicin- and nalidixic acid-restraint strain of P. stewartii. Acquisition of P. stewartii by corn flea beetles was considered positive if the rifampicin- and nalidixic acid-marked strain was recovered on selective media. To quantity the effect of transmission feeding period on percent transmission of P. stewartii by corn flea beetles, P. stewartii- infested corn flea beetles were allowed to feed on healthy corn seedlings for periods of 3, 6, 12, 24, 36, 48, and 72 h. After the appropriate transmission feeding period, leaf tissues surrounding the sites of feeding scars were cultured for the presence of the P. stewartii-marked strain. Transmission of P. stewartii was considered positive if the marked strain was recovered on selective media. Acquisition of P. stewartii occurred within 6 h and the percentage of corn flea beetles that had acquired P. stewartii after 72 h ranged from 68 to 94%. The change in P. stewartii acquisition by corn flea beetles (Y) with respect to acquisition feeding period (X) was best described by the Gompertz model, with R2 values ranging from 91 to 99%. The mean time for acquisition by 50% of the corn flea beetles was 36.5 ± 11.6 h. The minimum transmission feeding time required for corn flea beetles to transmit P. stewartii following a 48-h acquisition feeding period was less than 3 h. The percent transmission of P. stewartii by corn flea beetles was nearly 100% after a 48-h transmission feeding period and was 100% by 72 h. Among population growth models evaluated, the monomolecular model best described the relationship between percent transmission (Y) and transmission feeding periods (X), with R 2 values of up to 84%. However, a nonlinear form of the monomolecular model better quantified the relationship between percent transmission and transmission feeding period, because pseudo-R2 values ranged between 98.1 and 99.5%. The predicted transmission feeding time required for 50% of P. stewartii-infested corn flea beetles to transmit the pathogen was 7.6 ± 0.87 h. These results suggest that the corn flea beetle is a highly efficient vector that can quickly acquire and transmit P. stewartii, thereby requiring insecticide seed treatments and foliar insecticides that act quickly to prevent corn flea beetles from acquiring and transmitting P. stewartii to corn plants.

Chemical Concentration and Spatial Uniformity of a Premixing In-Line Injection System Attached to a Variable-Rate Orchard Sprayer

2021 ◽  
Vol 64 (6) ◽  
pp. 1977-1987
Author(s):  
Zhihong Zhang ◽  
Heping Zhu ◽  
Zhiming Wei ◽  
Ramon Salcedo
Keyword(s):  
Spatial Distribution ◽  
Duty Cycle ◽  
Spray Deposition ◽  
Injection System ◽  
List Type ◽  
Variable Rate ◽  
Chemical Concentration ◽  
Fluorescent Tracer ◽  
Distribution Uniformity ◽  
The Mean

HighlightsA newly developed premixing in-line injection system attached to a variable-rate orchard sprayer was evaluated.Tests were conducted to verify the in-line injection system performance using a vertical spray patternator.Concentration accuracy and spatial distribution uniformity were determined with a fluorescent tracer.Uniform spray mixtures were obtained for different spray viscosities and duty cycle combinations.Abstract. Pesticide spray application efficiency is highly dependent on the chemical concentration accuracy and spatial distribution uniformity. In this study, the performance of a newly developed premixing in-line injection system was evaluated when it was attached to a laser-guided, pulse width modulated (PWM), variable-rate orchard sprayer. The chemical concentration accuracy was determined with respect to spray deposition with a fluorescent tracer, and the spatial distribution uniformity was determined with spray deposits at different heights on a vertical spray patternator. Outdoor tests were conducted with 27 combinations of target chemical concentration (1.0%, 1.5%, and 2.0%), viscosity of the simulated pesticide (1.0, 12.0, and 24.0 mPa·s), and various spray outputs manipulated with PWM duty cycles. For each injection loop, the amounts of the chemical concentrate and water discharged into the mixing line were measured separately in response to preset target concentrations. The results showed that the measured concentrations were consistent across the patternator heights, spray viscosities, and duty cycle combinations. For all treatments, the mean absolute percentage error (MAPE) of the measured concentration was 6.96%, indicating that the concentration accuracy of the system was acceptable. The mean coefficient of variation was 3.35%, indicating that the spatial distribution uniformity of the system was in the desirable range. In addition, there was little variation in chemical concentration for spray mixtures collected at different heights on the patternator. Thus, the premixing in-line injection system could adequately dispense chemical concentrate and water to produce accurate concentrations and uniform spray mixtures for variable-rate nozzles to discharge to targets. Keywords: Environment protection, Precision pesticide application, Laser-guided sprayer, Tank mixture disposal, Specialty crop.

Ballistics and visual targeting in flea-beetles (Alticinae)

1995 ◽  
Vol 198 (9) ◽  
pp. 1931-1942 ◽  
Author(s):  
J Brackenbury ◽  
R Wang
Keyword(s):  
Flea Beetle ◽  
Rotational Energy ◽  
The Body ◽  
Translational Energy ◽  
High Contrast ◽  
Significant Preference ◽  
Flea Beetles ◽  
Mode 2 ◽  
Optical Grid ◽  
Targeting Accuracy

The kinematics of jumping was measured in seven species of flea-beetle (Alticinae). The accuracy of two species during targeted jumping was also investigated. Take-off accelerations ranged from 15 to 270 times gravity. Rotational energy accounted for 4&shy;21 % of the total translational energy. Two species were able to control jump direction and landing. When presented with a high-contrast optical grid, Chalcoides aurata exhibited two alternative jump modes. In mode 1 or wingless jumping, the body rotated continuously, the insect rarely landed on its feet and no discrimination was shown between landing on the black or white stripes of the grid. In mode 2 jumping, recruitment of the wings eliminated rotation and virtually ensured a feet-first landing; there was also a significant preference for jumping towards the black stripes. Aphthona atrocaerulea could alter take-off angle in order to strike targets at inclinations of 0&shy;90 &deg; to the horizontal. Targets consisting of a white illuminated cross on a black background were struck with equal accuracy, regardless of distance (within the normal jumping range). The beetle aimed specifically for the centre of the target and not for the high-contrast boundary. The distribution of hits about the target centre was radially symmetrical. Although take-off was wingless, rotation could be abolished in mid jump, within 10 ms, by extending the wings. This virtually guaranteed a feet-first landing. Targeting accuracy is discussed in the context of biomechanical steering mechanisms and visual control.

Sign in / Sign up

Export Citation Format

Share Document