Mikania micrantha is a serious invasive weed in Nepal. The worst effects of weed have been seen in Chitwan National Park which is a research area. Actually in the national park 37 plant species including 8 tree species, 9 shrub species,... more
Mikania micrantha is a serious invasive weed in Nepal. The worst effects of weed have been seen in Chitwan National Park which is a research area. Actually in the national park 37 plant species including 8 tree species, 9 shrub species, 13 herb species, 2 fern species and 5 climber species were found to be invaded by the weed in Baghmara Community Forest, Kumrose Community Forest and Eastern Sector . Many of them were found to be killed by invasion. During research starting from 1st July-15th November, 2011 each of blocks were divided into various quadrates of 20*25m representing 0.25% sampling intensity. However no biological efforts have been made to bring this weed under control in Nepal before this research. Laboratory studies undertaken in laboratory of Papua New Guinea 9PNG demonstrated that Mikania plants infected by rust Puccinia spegazzinii grew more slowly than uninfected Control plants. By 8th week following infection, rust infected branches length extension through growth slowed to under 0.9cm/week, compared to 8.1cm/week in control plants. This fungus can be an effective biological control agent for weed M. micrantha so it should be considered for introduction in Governmental level and released into Nepal. Key Words: Mikania, Nepal, Invasion, Puccinia.
Wheat, staple food of billions and one of the major crops in volume, is an excellent source of nutrition and income. However, its susceptibility to rust poses a constant threat to sustainable production and hence food security itself.... more
Wheat, staple food of billions and one of the major crops in volume, is an excellent source of nutrition and income. However, its susceptibility to rust poses a constant threat to sustainable production and hence food security itself. Wheat rust is the most urgent problem regarding the production of this irrevocably important crop. While cultural measures could lower down the extent of the infection, it isn't a permanent solution. Breeding for durable resistance is by far the most dependable solution to the problem. However even this has had many setbacks of pathogen evolution, climate change and other factors. Linked DNA markers show promise for achieving race-specific resistance genes in combinations aimed at their longevity. However, a national deployment strategy is inevitable for its success. The most promising activity so far is breeding for cultivars carrying durable resistance genes based on both minor and additive gene effect. However, using genetic engineering still faces the sentimental opposition of the public against genetically modified organisms. A lot has been done and a lot is to be done in order to grow rust free wheat in our fields. The paper discusses in brief about the major milestones and ongoing attempts regarding wheat breeding for rust resistance.
Abstract 1. The influence of infestation of the larval host plant Gentiana cruciata on the egg-laying preferences of the xerophilous ecotype of Alcon Blue butterfly (Maculinea alcon) was studied in a semi-dry grassland area (Aggtelek... more
Abstract 1. The influence of infestation of the larval host plant Gentiana cruciata on the egg-laying preferences of the xerophilous ecotype of Alcon Blue butterfly (Maculinea alcon) was studied in a semi-dry grassland area (Aggtelek Karst Region, Northern Hungary).2. We examined whether oviposition patterns of females differed when G. cruciata stems were uninfested compared with when they were infested by an aphid (Aphis gentianae) or a rust (Puccinia gentianae) species.3. Females laid more than 90% of their eggs on fertile, uninfested G. cruciata stems, although these stems comprised only ∼ 50% of the total stems available. Stems infested by aphids were similar to uninfested ones in properties that had a strong correlation with egg numbers, and yet there were significantly fewer eggs on infested stems than on intact ones.4. Females never laid eggs on parts of Gentiana stems infested by aphids, and the presence of Lasius paralienus ants, which have a mutualistic interaction with Aphis gentianae, did not increase the repulsive effect of aphids. Infection of Gentiana by Puccinia did not influence the egg-laying behaviour of females, even though the flowers and buds of infested stems exhibited a delayed development.5. Aphid infestation can influence butterfly oviposition patterns through both direct and indirect effects. The presence of aphids directly excluded oviposition, but our data also indicated the possibility of an indirect effect of aphid infestation. Stems that had no aphids at the last egg counting, but were infested prior to it, had significantly fewer eggs than those that were never infested.
Among ornamental species grown in Havana gardens and landscapes, Ipomea crassicaulis, Plumeria rubra, P. obtusa and Tabernaemontana divaricata are the most common. With the aim of establishing the distribution of species of Uredinales... more
Among ornamental species grown in Havana gardens and landscapes, Ipomea crassicaulis, Plumeria rubra, P. obtusa and Tabernaemontana divaricata are the most common. With the aim of establishing the distribution of species of Uredinales that affect these ornamentals, samples from plants with rust symptoms from different municipalities were collected. Specimen identification was made based on host, macroscopic observations of symptoms, analysis and characterization of the taxonomically important structures from each species. C. plumeriae was detected on P. obtusa and P. rubra in 2 and 10 municipalities respectively, whereas the presence of Uredo manilensis was recorded in 82% of studied municipalities, which demonstrate the wide distribution of these rust in Havana. Among the four Uredinales species reported in Cuba affecting Ipomoea crassicaulis, only Puccinia puta was detected, affecting 86.7% of sampled plants and in all studied municipalities. This is the first report of the incidence of Puccinia puta on Ipomoea crassicaulis in Havana.
Se describe e ilustra a Puccinia lateritia Berkeley & Curtis parasitando a Crusea sp. (Rubiaceae) del parque ecológico El Haya, Xalapa, Veracruz, Mexico.
Over the past several years, southern corn rust (SCR) outbreaks caused by the fungus Puccinia polysora have become increasingly problematic for corn growers in the United States. SCR is currently diagnosed through the visual examination... more
Over the past several years, southern corn rust (SCR) outbreaks caused by the fungus Puccinia polysora have become increasingly problematic for corn growers in the United States. SCR is currently diagnosed through the visual examination of disease symptoms and pathogen morphology, including pigmentation, size, shape, and location of fruiting structures. However, these characteristics are similar to those produced by the common corn rust fungus P. sorghi, confounding accurate visual diagnosis of SCR. Here we report the development of a real-time polymerase chain reaction assay that discriminates between P. polysora and P. sorghi. Sequences of the rDNA internal transcribed spacer region were determined for P. polysora and P. sorghi. 5-Carboxyfluorescein fluorophore-labeled hydrolysis probes that differed at 14 nucleotide positions between the species were developed from these data and used to screen DNA extracted directly from rust-infected corn leaves. Species-specific, reproducible ...
Se describe e ilustra a Puccinia abrupta var. Partheniicola Puccinia partheniicola Dietel y Holway (H. S. Jackson) J. Parmelee del parque ecológico El Haya, Xalapa, Veracruz, México.
Over the past several years, southern corn rust (SCR) outbreaks caused by the fungus Puccinia polysora have become increasingly problematic for corn growers in the United States. SCR is currently diagnosed through the visual examination... more
Over the past several years, southern corn rust (SCR) outbreaks caused by the fungus Puccinia polysora have become increasingly problematic for corn growers in the United States. SCR is currently diagnosed through the visual examination of disease symptoms and pathogen morphology, including pigmentation, size, shape, and location of fruiting structures. However, these characteristics are similar to those produced by the common corn rust fungus P. sorghi, confounding accurate visual diagnosis of SCR. Here we report the development of a real-time polymerase chain reaction assay that discriminates between P. polysora and P. sorghi. Sequences of the rDNA internal transcribed spacer region were determined for P. polysora and P. sorghi. 5-Carboxyfluorescein fluorophore-labeled hydrolysis probes that differed at 14 nucleotide positions between the species were developed from these data and used to screen DNA extracted directly from rust-infected corn leaves. Species-specific, reproducible identifications of the pathogens were made from as little as 50 pg of DNA within 30 min, and were reliably performed from both recent collections and herbarium specimens. This assay will be useful for rapid and accurate diagnosis of SCR, and could serve as a tool to monitor the distribution and incidence of the disease in the United States.
