Population dynamics of the plant pathogenic fungus Uncinula necator

1992 ◽  
Vol 70 (5) ◽  
pp. 942-946 ◽  
Author(s):  
Dan O. Chellemi ◽  
James J. Marois
Keyword(s):  
Population Growth ◽  
Pathogenic Fungus ◽  
Age Distribution ◽  
Reproductive Rate ◽  
Vitis Vinifera L ◽  
Uncinula Necator ◽  
Matrix Population Models ◽  
Net Reproductive Rate ◽  
Generation Times ◽  
Doubling Times

Cohort life tables were constructed and population parameters determined for Uncinula necator (Schw.) Burr. parasitizing the foliage of Vitis vinifera L. cv. Carignane at various temperatures. The net reproductive rate per individual conidium at 19, 22, 26, and 30 °C was 577, 2272, 1300, and 157 conidia per generation, respectively. Mean generation times ranged from 22.84 days at 19 °C to 13.60 days at 30 °C. Intrinsic growth rates (r) varied from 0.43 per day at 19 °C to 1.24 per day at 26 °C. Doubling times ranged from 0.56 days at 26 °C to 1.63 days at 19 °C. Matrix population models were used to project population growth. Stable age distributions at 19, 22, 26, and 30 °C were reached after 70, 50, 45, and 45 days, respectively. At a stable age distribution, greater than 96% of the population was contained in the first age-class (days 1 – 5). Key words: demography, cohort life table, grape powdery mildew, net reproductive rate, population growth rate.

Plant Resistance in Some Modern Soybean Varieties May Favor Population Growth and Modify the Stylet Penetration of Bemisia tabaci (Hemiptera: Aleyrodidae)

2021 ◽  
Author(s):  
Mauricélia F Almeida ◽  
Clébson S Tavares ◽  
Euires O Araújo ◽  
Marcelo C Picanço ◽  
Eugênio E Oliveira ◽  
...  
Keyword(s):  
Population Growth ◽  
Bemisia Tabaci ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Genetically Engineered ◽  
Population Increase ◽  
Net Reproductive Rate ◽  
Bt Toxin ◽  
Demographic Performance

Abstract Complaints of severe damage by whiteflies in soybean fields containing genetically engineered (GE) varieties led us to investigate the role of transgenic soybean varieties expressing resistance to some insects (Cry1Ac Bt toxin) and to herbicide (glyphosate) on the population growth and feeding behavior of Bemisia tabaci (Gennadius) MEAM1 (Hemiptera: Aleyrodidae). In the laboratory, the whiteflies reared on the GE Bt soybeans had a net reproductive rate (R0) 100% higher and intrinsic rate of population increase (rm) 15% higher than those reared on non-GE soybeans. The increased demographic performance was associated with a higher lifetime fecundity. In electrical penetration graphs, the whiteflies reared on the GE soybeans had fewer probes and spent 50% less time before reaching the phloem phase from the beginning of the first successful probe, indicating a higher risk of transmission of whitefly-borne viruses. Data from Neotropical fields showed a higher population density of B. tabaci on two soybean varieties expressing glyphosate resistance and Cry1Ac Bt toxin. These results indicate that some GE soybean varieties expressing insect and herbicide resistances can be more susceptible to whiteflies than non-GE ones or those only expressing herbicide resistance. Most likely, these differences are related to varietal features that increase host-plant susceptibility to whiteflies. Appropriate pest management may be needed to deal with whiteflies in soybean fields, especially in warm regions, and breeders may want to consider the issue when developing new soybean varieties.

Demography of the central california population of the Leopard Shark (Triakis semifasciata)

1992 ◽  
Vol 43 (1) ◽  
pp. 183 ◽  
Author(s):  
GM Cailliet
Keyword(s):  
Population Growth ◽  
Reproductive Rate ◽  
Shark Species ◽  
Sandbar Shark ◽  
Lemon Shark ◽  
Carcharhinus Plumbeus ◽  
Net Reproductive Rate ◽  
Leopard Shark ◽  
Triakis Semifasciata ◽  
Leopard Sharks

Demographic analyses can be quite useful for effectively managing elasmobranch fisheries. However, they require valid estimates of age-specific mortality and natality rates, in addition to information on the distribution, abundance, habits and reproduction of the population, to produce reliable estimates of population growth. Because such detailed ecological information is usually unavailable, complete demographic analyses have been completed for only four shark species: the spiny dogfish, Squalus acanthias; the soupfin shark, Galeorhinus australis; the lemon shark, Negaprion brevirostris; and most recently the sandbar shark, Carcharhinus plumbeus. In California, reliable estimates of age, growth, mortality, age at maturity, and fecundity are available only for the leopard shark, Triakis semifasciata. A demographic analysis of this species yielded a net reproductive rate (Ro) of 4.467, a generation time (G) of 22.35 years, and an estimate of the instantaneous population growth coefficient (r) of 0.067. If the mean fishing pressure over 10 years (F= 0.084) is included in the survivorship function, Ro and r are reduced considerably, especially if leopard sharks first enter the fishery at early ages. A size limit of 120 cm TL (estimated age 13 years), especially for female sharks, is tentatively proposed for the leopard shark fishery.

scholarly journals Potential-Growth Indicators Revisited: More Merits of Indication

2021 ◽  
Author(s):  
Dmitrii O. Logofet ◽  
Valerii N. Razzhevaikin
Keyword(s):  
Spectral Radius ◽  
Reproductive Rate ◽  
Matrix Population Models ◽  
Potential Growth ◽  
Net Reproductive Rate ◽  
Perennial Weed ◽  
Practical Applications ◽  
Structured Population ◽  
Calamagrostis Epigeios ◽  
Age Structured

The notion of potential-growth indicator came to being in the field of matrix population models long ago, almost simultaneously with the pioneering Leslie model for age-structured population dynamics, albeit the term has been given and the theory developed only recent years. The indicator represents an explicit function, R(L), of matrix L elements and indicates the position of the spectral radius of L relative to 1 on the real axis, thus signifying the population growth, or decline, or stabilization. Some indicators turned out useful in theoretical layouts and practical applications prior to calculating the spectral radius itself. The most senior (1994) and popular indicator, R0(L), is known as the net reproductive rate, and we consider two more ones, R1(L) and RRT(A), developed later on. All the three are different in what concerns their simplicity and the level of generality, and we illustrate them with a case study of Calamagrostis epigeios, a long-rhizome perennial weed actively colonizing open spaces in the temperate zone. While the R0(L) and R1(L) fail respectively because of complexity and insufficient generality, the RRT(L) does succeed, justifying the merit of indication.

scholarly journals Statistik demografi Dolichotetranychus floridanus Banks pada dua kultivar nanas (Ananas comosus (L.) Merr.)

2021 ◽  
Vol 10 (4) ◽  
pp. 660-667
Author(s):  
Ariffatchur Fauzi ◽  
Sugeng Santoso ◽  
Ali Nurmansyah
Keyword(s):  
Life Cycle ◽  
Population Growth ◽  
Generation Time ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Ananas Comosus ◽  
Reproduction Rate ◽  
Fruit Crops ◽  
Net Reproductive Rate ◽  
Pest Infestation

Pineapple is one of important fruit crops in Indonesia. One of important problems in pineapple production is pest infestation.. This study aims to investigate the biology, demography, and life cycle of Dolichotetranychus floridanus Banks on two pineapple cultivars (Queen and Cayenne). Observation of mite development (eggs-adults) were conducted every 6 hours.  Adults were observed everyday to record the fecundity.  The life table was constructed from the survivor and fecundity of D. floridanus. Based on this table, the variables of population growth, including gross reproduction rate (GRR), net reproductive rate (R0), mean generation time (T) and increase intrinsic rate (r) were determined. The results showed that the GRR, R0, and r of D. floridanus in the Queen cultivar were higher than Cayenne cultivar, while the T in the Queen cultivar was lower. Queen cultivar more suitable for D. floridanus than Cayenne cultivar.

scholarly journals Effect of flufenzine on population growth of Tetranychus urticae Koch (Acari: Tetranychidae)

Pesticidi ◽  
2002 ◽  
Vol 17 (1-2) ◽  
pp. 5-22 ◽  
Author(s):  
Dejan Marcic
Keyword(s):  
Population Growth ◽  
Tetranychus Urticae ◽  
Sublethal Effects ◽  
Reproductive Rate ◽  
Net Reproductive Rate ◽  
Development Stages ◽  
Female Survivors ◽  
Significant Statistical Difference ◽  
Jackknife Procedure ◽  
Tetranychus Urticae Koch

Effect of flufenzine on different parameters of Tetranychus urticae Koch population growth was investigated. The parameters were computed based on the life tables of female survivors of treatment at different development stages (egg, larva, protonymph, deutonymph) with acaricide concentrations that had caused >90% mortality. The intrinsic rates of increase acquired by the so-called jackknife procedure (rj) from female treatment survovors at egg (rj = 0.237) and larva (rj = 0.220) stages had no significant statistical difference from the corresponding values in control (rj = 0.230). Female survovors of treatment at protonymph or deutonymph stages had 2.1 and 4.5 times lower net reproductive rate (R0) against the control while the corresponding rj values in treatment (0.204 and 0.171) were statistically significantly lower than the control (0.255). Treatment with flufenzine at protonymph and deutonymph stages significantly disturbed the age structure of the surviving part of population. The article discusses the significance of sublethal effects of flufenzine in advancement of the acaricide's application strategy in controlling T. urticae.

scholarly journals MODELING DEMOGRAPHIC RESPONSE TO CONSTANT TEMPERATURE IN BRYOBIA RUBRIOCULUS (ACARI: TETRANYCHIDAE)

2014 ◽  
Vol 1 (1) ◽  
pp. 18-29
Author(s):  
Saeid Javadi Khederi ◽  
Mohammad Khanjani
Keyword(s):  
Population Growth ◽  
Reproductive Rate ◽  
Natural Increase ◽  
Growth Potential ◽  
Distribution Model ◽  
Thermal Constant ◽  
Temperature Threshold ◽  
Immature Stages ◽  
Net Reproductive Rate ◽  
Rate Of Increase

The demographic parameters of brown mite, Bryobia rubrioculus Scheuten were carried out in order to characterize the population growth potential at five constant temperatures: 20, 22.5, 25, 27.5 and 30ºC, 60 ± 5 % RH and 16: 8 (L: D) h. The highest intrinsic rate of natural increase (rm = 0.0243/day), net reproductive rate (R0 = 2.4 ♀/♀/T) and finite rate of increase (λ = 1.0245 day-1) values were determined at 22.5°C. The mean generation time (T) of the population ranged from 22.7 days at 30°C to 45.8 days at 20°C. The maximum and minimum survival rates (lx) were recorded at 22.5ºC and 30ºC. Survivorship data (lx) of adult females were summarized and compared using the shape and scale parameters of the Weibull frequency distribution model across. The age specific fecundity data (mx) was modeled as a function of time by using Polynomial model. The lower temperature threshold (t) and thermal constant (k) of the immature stages were estimated using Ikemoto and Takai linear model to be 12.85ºC and 279.7 degree days (DD), respectively. Of the non-linear models, the Analitis-1, Analitis-2, Analitis-3 and Analitis/Allahyari models were found to be the best for the modeling development rate of immature stages of B. rubrioculus. The optimal temperature for population growth of brown mite on apple was found at 22.5°C.

scholarly journals Biological Features and Population Growth of Two Southeastern European Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) Strains

Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 218 ◽  
Author(s):  
Nickolas G. Kavallieratos ◽  
Goran Andrić ◽  
Marijana Pražić Golić ◽  
Erifili P. Nika ◽  
Anna Skourti ◽  
...  
Keyword(s):  
Population Growth ◽  
Reproductive Rate ◽  
Tribolium Confusum ◽  
Intrinsic Rate Of Increase ◽  
Net Reproductive Rate ◽  
White Rice ◽  
Biological Features ◽  
Rate Of Increase ◽  
Potential Population ◽  
Coleoptera Tenebrionidae

A study of the biological features and the potential population growth between two laboratory strains of the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) from Greece and Serbia is conducted on cracked barley and cracked white rice. The results show that, at a species level, T. confusum is able to complete development on cracked barley but not on cracked white rice. Therefore, cracked white rice proves to be an unsuitable commodity for T. confusum. Larval development on cracked barley is significantly shorter for the Serbian compared to the Greek strain (37.7 and 49.7 days, respectively), but pupal development does not differ between the two strains (6.2 days for both strains). Additionally, male longevity does not differ between the Greek and Serbian strains (144.4 and 151.4 days, respectively), while female longevity is significantly shorter for the Serbian (151.7 days) compared to the Greek strain (186.6 days). Fecundity does not differ between the two strains (11.3 and 17.7 eggs/female for the Greek and the Serbian strain, respectively), whilst survival is higher for the Serbian strain on both tested commodities. The values of the net reproductive rate, the intrinsic rate of increase and the finite rate of increase on cracked barley are significantly higher for the Serbian (7.27 females/female, 0.025 female/female/day and 1.026, respectively) compared to the Greek strain (2.91 females/female, 0.014 females/female/day and 1.014, respectively). It therefore is expected that different strains of T. confusum may exhibit variable phenology as well as potential population growth. Additionally, we expect our results to have bearing on the management of this species.

Growth and demography of the Pacific Angle Shark (Squatina californica), based upon tag returns off California

1992 ◽  
Vol 43 (5) ◽  
pp. 1313 ◽  
Author(s):  
GM Cailliet ◽  
HF Mollet ◽  
GG Pittenger ◽  
D Bedford ◽  
LJ Natanson
Keyword(s):  
Population Growth ◽  
Age Determination ◽  
Growth Function ◽  
Reproductive Rate ◽  
Shark Species ◽  
Demographic Analysis ◽  
Net Reproductive Rate ◽  
Leopard Shark ◽  
The Pacific ◽  
Elasmobranch Species

Knowledge of the age, growth and demography of an organism can be quite useful for managing its fishery. However, for many elasmobranch species, no valid estimates of age, growth and therefore age-specific mortality and natality rates are available. Thus, even though the distribution, abundance, habits and reproduction of a population may be known, no reliable estimates of population growth are possible. As a result, detailed demographic analysis has been completed for only a few shark species (e.g. the California leopard shark, Triakis semlfasciata). All age-determination techniques attempted for the Pacific angel shark (Squatina californica) have met with difficulties. Recently, however, we have accumulated data on 69 tag-recaptures and have used this information to model a von Bertalanffy growth function (VBGF) to predict the growth of this commercially exploited shark species. We performed a demographic analysis of this species, which yielded a net reproductive rate (R0) of 2.25, a generation time (G) of 14.5 years, and an estimate of the instantaneous population growth coefficient (r) of 0.056 year-1, assuming that only natural mortality (M) was occurring, estimated to be 0.2 year-1. When reasonable estimates of fishing mortality (F) are included in the survivorship function, Ro and r are reduced considerably. Presently, Pacific angel sharks first enter the fishery at the same size and age at which they first reproduce. Until accurate estimates of M and Fare available, it would be prudent to set a size limit considerably above the size at first reproduction to protect the Pacific angel shark in California.

scholarly journals Potential-Growth Indicators Revisited: Higher Generality and Wider Merit of Indication

Mathematics ◽  
2021 ◽  
Vol 9 (14) ◽  
pp. 1649
Author(s):  
Dmitrii O. Logofet ◽  
Valerii N. Razzhevaikin
Keyword(s):  
Spectral Radius ◽  
Reproductive Rate ◽  
Matrix Population Models ◽  
Potential Growth ◽  
Net Reproductive Rate ◽  
Perennial Weed ◽  
Practical Applications ◽  
Structured Population ◽  
Calamagrostis Epigeios ◽  
Age Structured

The notion of a potential-growth indicator came to being in the field of matrix population models long ago, almost simultaneously with the pioneering Leslie model for age-structured population dynamics, although the term has been given and the theory developed only in recent years. The indicator represents an explicit function, R(L), of matrix L elements and indicates the position of the spectral radius of L relative to 1 on the real axis, thus signifying the population growth, or decline, or stabilization. Some indicators turned out to be useful in theoretical layouts and practical applications prior to calculating the spectral radius itself. The most senior (1994) and popular indicator, R0(L), is known as the net reproductive rate, and we consider two others, R1(L) and RRT(A), developed later on. All the three are different in terms of their simplicity and the level of generality, and we illustrate them with a case study of Calamagrostis epigeios, a long-rhizome perennial weed actively colonizing open spaces in the temperate zone. While the R0(L) and R1(L) fail, respectively, because of complexity and insufficient generality, the RRT(L) does succeed, justifying the merit of indication.

scholarly journals Effects of UV Radiation on Egg Hatching Population Growth and Reproductive Parameters of Indianmeal Moth Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

2020 ◽  
pp. 130-142
Author(s):  
Akram Bakhshi ◽  
Ali Asghar Talebi ◽  
Yaghoub Fathipour ◽  
Ali Mirshekar
Keyword(s):  
Population Growth ◽  
Exposure Time ◽  
Growth Parameters ◽  
Plodia Interpunctella ◽  
Reproductive Rate ◽  
Intrinsic Rate Of Increase ◽  
Egg Hatching ◽  
Net Reproductive Rate ◽  
Rate Of Increase ◽  
Population Growth Parameters

In this research, three age groups of Plodia interpunctella (Hübner) eggs (1-, 2- and 3-day-old eggs) were exposed to ultraviolet irradiation (UVC) with 254nm wavelength for 0.5, 1, 1.5, 2, 4, 8, 16, 24, 32 and 40 minutes, under controlled conditions. The effect of UVC-irradiation on reproduction and population growth parameters investigated for eggs irradiated for 0.5, 1 and 1.5 minutes. The percentage of egg hatching decreased with increase in UVC exposure time, while for each exposure time, the older eggs were more sensitive than the younger ones. The results indicated that different exposure times of UVC-irradiation could affect the reproduction and population growth parameters. The highest value of net fertility rates was observed in 1, 2 and 3-day-old eggs which were treated with 0.5 min exposure. Both the intrinsic rate of increase (rm) and the net reproductive rate (R0) decreased with increasing exposure time from 0.5 to 1.5 min while the mean generation time (Tc) and doubling time (DT) increased within this irradiation range. The lowest amount of rm was obtained in 1, 2 and 3-day-old eggs which were treated with 1.5 min exposure time. The results showed that UVC-irradiation is an appropriate technique for controlling P. interpunctella.

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