Puccinia subnitens: An Obscure Rust Pathogen Little-Known for More than a Century

2014 ◽  
Vol 15 (3) ◽  
pp. 105-111
Author(s):  
Robert M. Harveson
Keyword(s):  
Life Cycle ◽  
Sugar Beet ◽  
Host Range ◽  
Host Species ◽  
Complex Life Cycle ◽  
Narrow Host Range ◽  
Rust Diseases ◽  
Rust Pathogen

Sugar beet seedling rust, caused by Puccinia subnitens, is a rarely occurring but essentially harmless disease in sugar beet production. However, it has caused substantial but sporadic losses to commercial spinach growers. It has the typically complex life cycle of a macrocyclic rust pathogen, but is also unusual because it is one of the few documented heteroecious rust diseases where the early spore stages (pycnial and aecial) occur on the economic host while the normally damaging, repeating, uredial stage is found on the feral, noneconomic host. Most significantly, it was one of the first heteroecious rust diseases recognized to have the ability to infect numerous, distinct host species with the aecial stage while maintaining a relatively narrow host range for its uredial and telial stages. Accepted 6 June 2014. Published 25 July 2014.

Combining data from morphological traits and genetic markers to determine transmission cycles in the tape worm, Echinococcus granulosus

Parasitology ◽  
1998 ◽  
Vol 117 (2) ◽  
pp. 185-192 ◽  
Author(s):  
A. J. LYMBERY
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Host Range ◽  
Genetic Markers ◽  
Definitive Host ◽  
Host Species ◽  
Phenotypic Variance ◽  
Blade Length ◽  
Total Length ◽  
Transmission Cycles

Species of Echinococcus (Cestoda: Taeniidae) require 2 mammalian hosts to complete their life-cycle; a carnivorous definitive host, and a herbivorous or omnivorous intermediate host. For most species of Echinococcus, the definitive host range is restricted to 1 or a few species, but the intermediate host range is very broad. Programmes to control hydatid disease attempt to break the life-cycle of the parasite and their effectiveness is therefore enhanced by an understanding of local patterns of transmission. Although it is known that the rostellar hooks of protoscoleces may be influenced by the species of intermediate host in which they develop, the application of this knowledge to infer transmission cycles has been limited, because the intermediate host effect has not been isolated from other environmental and genetic components of phenotypic variance. This study presents a method for separating these potentially confounding genetic and environmental effects, by combining quantitative genetic analyses of hook traits with data on population structure from neutral genetic markers. The method was applied to 5 hook traits (hook number, total length of large hooks, blade length of large hooks, total length of small hooks, blade length of small hooks) measured on protoscoleces from 2 intermediate host types (sheep and macropod marsupials) in Australia. Although genetic variance was similar for all traits, they differed markedly in the extent of environmental variance attributed to development in different host types. Total length of small hooks was the trait most affected, with 49–60% of phenotypic variance being explained by environmental differences between intermediate host species. Blade length of small hooks was least affected, with none of the phenotypic variance due to intermediate host origin. These data suggest that hook measurements of adult worms from naturally infected definitive hosts could be used to determine the intermediate host species from which infection was acquired, if the appropriate traits are measured.

scholarly journals Diversity, Host Range and Distribution of Mistletoes along Steep Altitudinal Gradient of Tribhuvan Highway, Central Nepal

Our Nature ◽  
1970 ◽  
Vol 8 (1) ◽  
pp. 106-117
Author(s):  
G.P. Joshi ◽  
M.P. Devkota
Keyword(s):  
Host Range ◽  
Host Species ◽  
Suitable Habitat ◽  
Altitudinal Distribution ◽  
Narrow Host Range ◽  
Central Nepal ◽  
The Family ◽  
Fragmented Forests ◽  
Major Factors ◽  
High Degree

A total of 11 mistletoe species, eight belonging to five genera in the family Loranthaceae and three species belonging to two genera in the family Viscaceae were documented from 43 host species belonging to 24 unrelated host families along Tribhuvan highway, central Nepal. Wide host range of Scurrula species (Loranthaceae) showed that they were more generalist and successfully parasitized as many hosts as encountered, while Viscaceae mistletoes showed narrow host range and high degree of host specificity since they infected a limited number of hosts. The irregular and patchy distribution of mistletoe along the highway was governed by three major factors: forest structure, site mesoclimate and availability of suitable host species. Marginal fragmented forests located along the warm sunny slopes of highway were found as most suitable habitat. Warmer southern sunny slopes, between Sinbhanjyang to Bahise Dobhan, favoured wider altitudinal distribution range of mistletoe compared to cold and moist northern slopes.DOI: 10.3126/on.v8i1.4317

scholarly journals Complex life cycle, broad host range and adaptation strategy of the intranuclear Paramecium symbiont Preeria caryophila comb. nov

2018 ◽  
Vol 94 (7) ◽  
Author(s):  
Alexey Potekhin ◽  
Michael Schweikert ◽  
Irina Nekrasova ◽  
Valerio Vitali ◽  
Sabine Schwarzer ◽  
...  
Keyword(s):  
Life Cycle ◽  
Host Range ◽  
Adaptation Strategy ◽  
Complex Life Cycle ◽  
Broad Host Range

The coevolutionary potential of a ‘generalist’ parasite, the hen flea Ceratophyllus gallinae

Parasitology ◽  
1997 ◽  
Vol 115 (4) ◽  
pp. 419-427 ◽  
Author(s):  
F. TRIPET ◽  
H. RICHNER
Keyword(s):  
Host Range ◽  
Host Specificity ◽  
Host Species ◽  
Narrow Host Range ◽  
Parasite Infestation ◽  
Highly Correlated ◽  
Host Parasite ◽  
Number Of Individuals ◽  
Ceratophyllus Gallinae

Hosts exert selection pressures on their parasites and it is often assumed that host–parasite coevolution with each host is less intense in a generalist parasite than for a parasite with a narrow host range. Selection pressure on the parasite, however, is rather determined by host specificity, i.e. the relative importance of each host, than simply by the range of hosts. The determination of host specificity requires an assessment of the prevalence and intensity of parasite infestation within each host's nests, as well as the local abundance of each host species. Since the hen flea, Ceratophyllus gallinae, is a rather generalist parasite of birds it could be concluded that there has been weak coevolution with each of its hosts. By reviewing the literature on the prevalence and intensity of hen flea infestations in bird nests we estimated the number of individuals produced in the nest of each host species. The comparative analysis shows (1) that the prevalence of infestation is highest in hole-nesting avian families, (2) that prevalence and intensity of infestation among bird families are highly correlated, and (3) that hole-nesting Paridae have the highest intensities of infestation and harbour the majority of the flea population. These results underline the fleas' potential for coevolution with Paridae despite their extensive host range.

scholarly journals Biology, Ecology, and Management Strategies for Pea Aphid (Hemiptera: Aphididae) in Pulse Crops

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ramandeep Kaur Sandhi ◽  
Gadi V P Reddy
Keyword(s):  
Life Cycle ◽  
Host Range ◽  
Chemical Control ◽  
Management Practices ◽  
Management Strategies ◽  
Pea Aphid ◽  
Complex Life Cycle ◽  
Broad Host Range ◽  
Grass Pea ◽  
Pulse Crops

Abstract Pea aphid, Acyrthospihon pisum (Harris) (Hemiptera: Aphididae), is one of the key pests of pulse crops worldwide. The aphid has a broad host range, infesting crops such as faba bean, lupin, alfalfa, lentil, chickpea, grass pea, and pea. This broad host range with a complex life cycle and ability to quickly adapt to new environmental conditions make it difficult to control this pest. Different studies focusing on the biology, ecology, and management practices of A. pisum, along with case studies conducted on different integrated pest management strategies such as host plant resistance, cultural, genetic, biological, and chemical control are reviewed here.

Trade-Offs with Growth Limit Host Range in Complex Life-Cycle Helminths

2020 ◽  
pp. E000-E000
Author(s):  
Daniel P. Benesh ◽  
Geoff A. Parker ◽  
James C. Chubb ◽  
Kevin D. Lafferty
Keyword(s):  
Life Cycle ◽  
Host Range ◽  
Complex Life Cycle ◽  
Trade Offs ◽  
Growth Limit

Ultrastructural analysis of “Sensory” surface nerve endings and “putative” neurotransmitter sites in Schistosoma mansoni Miracidia

1989 ◽  
Vol 47 ◽  
pp. 962-963
Author(s):  
Betty Ruth Jones ◽  
Steve Chi-Tang Pan
Keyword(s):  
Nervous System ◽  
Life Cycle ◽  
Schistosoma Mansoni ◽  
Snail Host ◽  
Complex Life Cycle ◽  
Rational Approach ◽  
Effective Control ◽  
The Social ◽  
Social And Economic Development ◽  
Basic Biology

INTRODUCTION: Schistosomiasis has been described as “one of the most devastating diseases of mankind, second only to malaria in its deleterious effects on the social and economic development of populations in many warm areas of the world.” The disease is worldwide and is probably spreading faster and becoming more intense than the overall research efforts designed to provide the basis for countering it. Moreover, there are indications that the development of water resources and the demands for increasing cultivation and food in developing countries may prevent adequate control of the disease and thus the number of infections are increasing.Our knowledge of the basic biology of the parasites causing the disease is far from adequate. Such knowledge is essential if we are to develop a rational approach to the effective control of human schistosomiasis. The miracidium is the first infective stage in the complex life cycle of schistosomes. The future of the entire life cycle depends on the capacity and ability of this organism to locate and enter a suitable snail host for further development, Little is known about the nervous system of the miracidium of Schistosoma mansoni and of other trematodes. Studies indicate that miracidia contain a well developed and complex nervous system that may aid the larvae in locating and entering a susceptible snail host (Wilson, 1970; Brooker, 1972; Chernin, 1974; Pan, 1980; Mehlhorn, 1988; and Jones, 1987-1988).

The Output of First Stage Larvae by Cats Infested with Aelurostrongylus abstrusus

1968 ◽  
Vol 42 (3-4) ◽  
pp. 295-298 ◽  
Author(s):  
J. M. Hamilton ◽  
A. W. McCaw
Keyword(s):  
Life Cycle ◽  
Great Britain ◽  
Intermediate Host ◽  
World Wide ◽  
Wide Distribution ◽  
Clinical Disease ◽  
Complex Life Cycle ◽  
Patent Period ◽  
Aelurostrongylus Abstrusus

Aelurostrongylus abstrusus, the lungworm of the cat, has a world wide distribution and has been reported from countries as far apart as America, Great Britain and Palestine. It has a complex life cycle insofar as a molluscan intermediate host is essential and it is possible that auxiliary hosts also play an important part. In Britain, the incidence of active infestation of cats with the parasite has been recorded as 19·4% (Lewis, 1927) and 6·6% (Hamilton, 1966) but the latter author found that, generally, the clinical disease produced by the parasite was of a mild nature. It is known that the average patent period of the infestation in the cat is 8–13 weeks and it seems likely that, in that time, a considerable number of first stage larvae would be evacuated. Information on that point is not available and the object of the following experiment was to ascertain the number of larvae produced by cats during the course of a typical infestation.

scholarly journals Ecological characteristics of Varroa destructor (parasitiformes, varroidea) and its environmental capacity as a key factor for development of varroosis panzootia

2012 ◽  
Vol 46 (5) ◽  
pp. 8-14
Author(s):  
I. A. Akimov ◽  
O. P. Korzh
Keyword(s):  
Life Cycle ◽  
Honey Bee ◽  
Host Species ◽  
Varroa Destructor ◽  
Varroa Mite ◽  
Environmental Capacity ◽  
Ecological Characteristics ◽  
High Pathogenicity ◽  
Key Factor

Ecological Characteristics of Varroa destructor (Parasitiformes, Varroidae) and Its Environmental Capacity as a Key Factor for Development of Varroosis Panzootia. Akimov I. A., Korzh O. P. - By means of formalized schematic models of relationship with hosts the varroa mite uniqueness as a parasite is shown. The life cycle of this species requires the change of a host species at different stages of their development and physiological states. Thus the mite parasitizes not only a separate bee but a whole hive. The fact that the whole hive but not a single bee dies during varroosis development supports this idea. The impetus for this type of parasitism is the relative constancy of the environment in the hive supported by bees even in winter. Exactly this fact causes high pathogenicity of the varroa for the honey bee and its control complexity.

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