Chrysomyxa himalensis (needle rust of spruce).

2021 ◽  
Author(s):  
Keyword(s):  
Life Cycle ◽  
Latent Infection ◽  
Rust Fungus ◽  
Himalayan Region ◽  
Native Range ◽  
Southern Asia ◽  
The Usa ◽  
Accidental Introduction

Abstract C. himalensis is a heteroecious rust completing different stages of its life cycle on different plants. The teleomorph occurs on Rhododendron species in the Himalayan region of southern Asia; an anamorph is reported on Picea species. Although not a major problem in its narrow native range, this rust fungus could be more damaging as an invasive on Picea and Rhododendron. The fungus is a Regulated Pest for the USA; it is considered potentially damaging to Rhododendron by CAST (2002). Small amounts of perennial or latent infection may be overlooked, therefore accidental introduction of the rust could occur through importation of infected germplasm by the horticultural industry or by flower enthusiasts.

Chrysomyxa abietis (needle rust of fir).

2021 ◽  
Author(s):  
Keyword(s):  
Life Cycle ◽  
New Zealand ◽  
North America ◽  
Rust Fungus ◽  
Significant Problem ◽  
Northern Europe ◽  
Native Range ◽  
Obligate Parasite ◽  
The Usa ◽  
Accidental Introduction

Abstract C. abietis is a microcyclic rust fungus; an obligate parasite completing its life cycle on species of Picea (spruce). Only the current year's needles of Picea are infected and those needles are shed early. Reported from northern Europe and Asia, the fungus is a Regulated Pest for the USA. It is absent from North America, where susceptible species are native, and Australia and New Zealand, where they are introduced. Although usually not a significant problem in its native range, because conditions are not favourable for heavy infections every year (Smith et al., 1988; Hansen, 1997), this rust could be more damaging as an invasive in other temperate areas. Due to the fact that small amounts of infection may be overlooked, accidental introduction could occur through importation of infected seedlings or young trees.

Thekopsora areolata (cherry spruce rust).

2021 ◽  
Author(s):  
Keyword(s):  
Life Cycle ◽  
New Zealand ◽  
North America ◽  
Rust Fungus ◽  
Native Range ◽  
Obligate Parasite ◽  
The Usa ◽  
The One ◽  
Accidental Introduction

Abstract T. areolata is a heteroecious rust fungus; an obligate parasite with stages of its life cycle on cones of Picea species and leaves of Prunus spp. Reported from Europe and Asia, the fungus is a Regulated Pest for the USA. It is absent from North America, where susceptible species are native or introduced, and Australia and New Zealand, where such species are introduced. Although usually not a major problem in its native range, this rust could be more damaging as an invasive in other temperate areas. Due to the fact that small amounts of infection may be overlooked, accidental introduction could occur through importation of infected cones carrying aeciospores. The one known introduction to North America involved a tree of Prunus sp. in a garden, from which there was no documented spread.

Chrysomyxa rhododendri (European rhododendron rust).

2021 ◽  
Author(s):  
Keyword(s):  
Invasive Species ◽  
Life Cycle ◽  
New Zealand ◽  
Rust Fungus ◽  
Ornamental Plants ◽  
Sexual Stage ◽  
The Usa ◽  
Asexual Form ◽  
The Uk ◽  
Accidental Introduction

Abstract C. rhododendri is a heteroecious rust fungus; an obligate parasite completing stages of its life cycle on different plants. Mating of haploid strains occurs on species of Picea, followed by the production of asexual aeciospores that infect Rhododendron species. Another asexual form producing urediniospores occurs on Rhododendron, followed by the production of teliospores (the sexual stage). All stages are known from Europe. The fungus was reported in 1954 on Rhododendron in the northwestern USA, but the aecial form has not been found in North America. The fungus is a Regulated Pest for the USA; it has been introduced into the UK, New Zealand and Australia. As an invasive species, this rust is damaging on species of Picea and Rhododendron. As latent infections on Rhododendron can be overlooked, accidental introduction of the rust may occur through the importation of these popular ornamental plants (Savile, 1973).

Puccinia gladioli.

2021 ◽  
Author(s):  
Keyword(s):  
South Africa ◽  
North Africa ◽  
Rust Fungus ◽  
Life Stages ◽  
Sexual Stage ◽  
Native Range ◽  
The West ◽  
The Usa ◽  
Asexual Form ◽  
Accidental Introduction

Abstract P. gladioli is a heteroecious rust fungus, an obligate parasite with alternating life stages on different plants. The asexual form occurs on species of Valerianella, producing aeciospores that then infect Gladiolus species. The production of teliospores, the sexual stage, on Gladiolus, completes the cycle. Both stages are known in Europe, North Africa and southwestern Asia, but only the aecial form has been reported in North America, and only on the west coast. The fungus is a Regulated Pest for the USA (Wise et al., 2004) and is absent from South Africa and Australia, where other Gladiolus species are native or naturalized. Although not a significant problem in its native range, this rust fungus could be damaging as an invasive in other temperate areas. Small amounts of infection may be overlooked; therefore accidental introduction of the rust could occur through importation of infected germplasm by the horticultural industry or flower enthusiasts.

Cronartium flaccidum (Scots pine blister rust).

2021 ◽  
Author(s):  
Keyword(s):  
Life Cycle ◽  
Host Species ◽  
Rust Fungus ◽  
Sexual Stage ◽  
Eastern Asia ◽  
Alternate Host ◽  
Blister Rust ◽  
The Usa ◽  
Dicotyledonous Plants ◽  
Accidental Introduction

Abstract C. flaccidum is a heteroecious rust fungus, completing different stages of its life cycle on different plants. Mating of haploid strains occurs on species of Pinus, followed by the production of aeciospores, which infect various species of herbaceous dicotyledons. An asexual stage producing urediniospores occurs on the dicotyledonous plants, followed by the production of teliospores, the sexual stage, that germinate to form basidiospores that infect pines thus completing the cycle. A closely-related autoecious rust, Endocronartium (Peridermium) pini, only infects Pinus hosts. C. flaccidum is known from Europe and parts of northern and eastern Asia; it is a Regulated Pest for the USA (USDA/APHIS, 2008). As an invasive in other temperate areas, this rust could be damaging on native and introduced pines or the alternate host species. The infections on pines develop slowly, therefore the fungus might be overlooked, such that accidental introduction of the rust could occur through the importation of conifer [Pinopsida] seedlings or trees.

scholarly journals Variability of nitrogen content in the needles of Douglas-fir (Pseudotsuga menziesii Mir/Franco) provenances

Genetika ◽  
2011 ◽  
Vol 43 (2) ◽  
pp. 407-417 ◽  
Author(s):  
Vera Lavadinovic ◽  
Vasilije Isajev ◽  
Zoran Miletic ◽  
Milun Krstic
Keyword(s):  
Nitrogen Content ◽  
Mineral Nutrition ◽  
Douglas Fir ◽  
Native Range ◽  
Adaptive Potential ◽  
Small Areas ◽  
Physiological Processes ◽  
Provenance Test ◽  
The Usa ◽  
Geographical Characteristics

Nitrogen content in the needles of twenty Douglas-fir provenances, originating from different sites within the native range of the species in the USA, was studied in a Douglas-fir provenance test established at the montane beech site on acid brown soil. Based on the variability of nitrogen content in the needles, the intensity and dynamics of the physiological processes of Douglas-fir mineral nutrition were analyzed as the indicators of Douglas-fir adaptive potential to the sites in Serbia. All the trees of the study provenances were of the same age and grown under the same site and population conditions. The quantities of nitrogen absorbed in Douglas-fir needles were correlated with the geographical characteristics of the native sites of the observed provenances. The differences in nitrogen content in Douglas-fir needles point out the variability in the intensity of the physiological processes in the genotypes of the different provenances. Since the study Douglas-fir trees are cultivated on relatively small areas, in more or less equal general conditions, it can be concluded that the parameters of mineral nutrition depend on the genotypes constituting the gene pool of the study Douglas-fir provenances.

Puccinia buxi.

2021 ◽  
Author(s):  
Keyword(s):  
Life Cycle ◽  
North America ◽  
Southern Hemisphere ◽  
Latent Infections ◽  
Growth And Survival ◽  
The Usa

Abstract P. buxi is an autoecious microcyclic rust, completing its life cycle with two spore forms on one host. It is native to parts of Europe and Asia. An introduction to the USA, is evidence that it can be invasive with respect to other temperate countries, particularly because its hosts in the genus Buxus are often propagated vegetatively and may carry latent infections. Boxwoods have long been popular as ornamentals, therefore the rust's current absence from North America and temperate regions of the southern hemisphere is puzzling; in the earliest introductions of the host, the pathogen would probably have been ignored or overlooked. Conditions of boxwood cultivation may discourage the rust's growth and survival.

scholarly journals Evaluation of the rust fungus Puccinia rapipes for biological control of Lycium ferocissimum (African boxthorn) in Australia: Life cycle, taxonomy and pathogenicity

2019 ◽  
Vol 123 (11) ◽  
pp. 811-823 ◽  
Author(s):  
Kylie B. Ireland ◽  
Gavin C. Hunter ◽  
Alan Wood ◽  
Caroline Delaisse ◽  
Louise Morin
Keyword(s):  
Biological Control ◽  
Life Cycle ◽  
Rust Fungus

ECONOMIC-DEMOGRAPHIC DEPENDENCY RATIO IN A LIFE-CYCLE MODEL

2019 ◽  
Vol 24 (7) ◽  
pp. 1635-1673
Author(s):  
Sau-Him P. Lau ◽  
Albert K. Tsui
Keyword(s):  
Life Cycle ◽  
Population Aging ◽  
Retirement Age ◽  
Dependency Ratio ◽  
Life Cycle Model ◽  
Cycle Model ◽  
Stochastic Mortality ◽  
The Usa ◽  
Definition Of ◽  
Parameter Values

The conventional dependency ratio based on cohort-invariant cutoff points could overstate the true burden of population aging. Using optimal cohort-varying years of schooling and retirement age in a life-cycle model, we propose a modified definition of dependency ratio. We compare the proposed economic-demographic dependency ratio (EDDR) with the conventional definition and find that the conventional dependency ratio of the USA is projected to increase by 0.105 from 2010 to 2060, which is an over-projection of 86% when compared with the projected increase of 0.015 in the EDDR over the same period. Sensitivity analysis suggests that our finding is quite robust to reasonable changes in parameter values (except for one parameter), and the magnitude of over-projection ranges mainly from 0.079 to 0.102 (i.e., 75% to 97%). We follow the well-established Lee–Carter model to forecast stochastic mortality and employ the method of expanding duration to decompose the sources of over-projection.

Sign in / Sign up

Export Citation Format

Share Document