Showing papers on "Rust published in 1973"

The biology of Puccinia chondrillina a potential biological control agent of skeleton weed

Abstract: SUMMARY During investigations on the parasites of Chondrillajuncea in the Mediterranean region, the rust, Puccinia chondrillina, was found to be one of the most damaging. This macrocyclic and autoecious rust which is specific to the genus Chondrilla, remains active throughout the year and attacks all stages and all parts of the plant. In the Mediterranean region the rust appears to multiply solely by the uredo-stages and the teleutospores produced at the end of the summer have no obvious role in the life-cycle of the fungus. The uredospores germinated at temperatures of 0–36 °C and were used for inoculation of Chondrilla seedlings in the greenhouse. The rust occurs from the cold continental climates of southern Siberia to the hot, Mediterranean ones of Portugal and North Africa. In many situations the rust has been found to play an important role in the reduction of C. juncea populations. Young seedlings were highly susceptible to attack and were often destroyed. Older rusted plants gave many fewer viable seeds than healthy plants and were also often unable to produce new rosettes from their roots.

Genetics of pathogenicity in three races of leaf rust on four wheat varieties

Abstract: Populations of self-fertilized cultures of races 9, 11 and 161, "backcross" selfed progeny of race 11, F1 cultures of races 9 × 11 and 11 × 161, and F2 cultures of races 9 × 161 were used to study ...

Rust inhibitors for hydrocarbon fuels

Abstract: A novel rust inhibitor mixture for use in hydrocarbon fuels comprising an Alpha -olefin-maleimide copolymer and a hydrocarbyl amine, amide or imidazoline is disclosed. A method of inhibiting rust in fuel oils is also disclosed.

The construction and operation of a dew‐simulation chamber

Abstract: SUMMARY A variable dew-point chamber which simulates dew fall on plant parts within a temperature range of I-35? C is described, with technical data on construction and performance. Although designed to obtain uniform infections of cereal leaves following their inoculation with rust uredospores in a settling tower, possible wider uses of the apparatus in biological research are discussed.

The effect of yellow rust and its control on the yield of Joss Cambier winter wheat.

Abstract: SUMMARY Foliar sprays of fungicides were evaluated in a field where winter wheat cv. Joss Cambier was subject to a severe natural infection of yellow rust (Puccinia striiformis Westend.). Almost complete freedom from the disease was achieved on the leaves from repeated applications of BAS 3170F. This material prevented the development of appreciable disease for up to four weeks after spraying. Other chemicals gave varying degrees of protection but most lacked persistence. Control of ear infection was less satisfactory. The untreated crop, which was heavily attacked by yellow rust, showed a yield reduction of 34 per cent compared with the crop receiving greatest protection. The relationship between yield and yellow rust at growth stage 11.1 was statistically significant; the loss of yield recorded was 0-022 t/ha for each one per cent increase in the level of yellow rust on the flag leaf.

Les rouilles du Peuplier en France Systematique et repartition du stade uredien

Abstract: Poplar rusts in France – Classification and distribution. The classification and distribution of Poplar rust in France are described in detail. An illustrated key is provided for urcdia.

The oversummering and dispersal of inoculum of Puccinia striiformis.

Abstract: Stripe rust (Puccinia striiformis) was found on grasses Urediospores were trapped on rod spore samplers in wheat-growing regions and in adjacent mountains of exposed in the field only after stripe rust was Oregon during late spring only after the disease was well well established on the wheat crop The number of spores established on the wheat crop Disease incidence on these trapped followed closely the development of the disease grasses diminished during summer, and approached zero in wheat fields near the traps Throughout northeastern during August Stripe rust was seen less frequently on Oregon, urediospores moved predominantly from west to grasses in the mountains than on grasses in the wheatland east Most plants of susceptible grass species were free from The results suggest that urediospores which infect the stripe rust in the field, but became infected when fall wheat crop come from rust that oversummers on inoculated in the greenhouse Commercial wheat plantings residual green wheat and grasses within the wheatland served as the sources of inoculum for natural infections of wheat in plots located up to 64 km from wheat fields Phytopathology 63:13-17 The source of stripe rust (Puccinia striiformis established wheat plots in the mountains at various West) inoculum for fall infection of Oregon's wheat distances from wheatland (Fig 1) Ten wheat crop has remained undetermined since the discovery cultivars, differing in their susceptibility to stripe of the disease there in 1916 (4) The fungus has no rust, were grown at each site (Table 2) Nearly all the known alternate host, so urediospores must serve as wheat grown commercially in northeastern Oregon primary inoculum The critical period in the disease during this study were the cultivars Gaines, Moro, and cycle is the period between ripening of the wheat Omar Druchamp was also grown in the Willamette crop in July and the emergence of the new crop in Valley October (12) During this interval, there is very little Two plots consisting of a 2-m row of each cultivar green wheat in Oregon because of the dry summers, were established at each location in the fall Poultry We occasionally found stripe rust on ripening wheat wire cages (2 m X 6 m X 15 m), with rodent shields and residual green wheat during July and early August (12) The earliest when stripe rust was found on the fall-sown crop was in December, and then only Wheot-Growing Area in early-sown fields Since apparently little stripe rust oversummers on wheat in Oregon, we conducted investigations to determine whether rust oversummers on hosts other than wheat or whether inoculum moves in from some distant source MATERIALS AND METHODS-Wheat in northeastern Oregon is grown in three areas separated • '" by mountains (Fig 1) These are the Columbia Basin, rx i ;:a _:i ! consisting of Wasco, Sherman, Gilliam, Morrow, and - ,"•I : Umatilla Counties; the grande Ronde Valley of 'o, I, L-_, '-I adjacent mountains Observations were also made in ) i"i'" iI the Cascades, which separate western and eastern L l i I" " ' Oregon, in the Willamette Valley, and in the Coast -"-)--I-!:', j_ Mountains Stripe rust collected from grasses or wheat was Fig 1 Wheat-growing areas of Oregon and location of the tested in the greenhouse for pathogenicity on Mountain plots: 1 =Mary's Peak, 975 m; 2 =Tupper, 1,311 Oregon's commercial wheat cultivars and grasses in; 3 = Dale, 1,615 m; 4 = Meachum, 1,219 in; and 5 To study long-distance spore dispersal, we Tollgate, 1,524 m

Maintenance of the rust, puccinia poarum, on its alternate hosts under controlled conditions

Abstract: SUMMARY Methods by which the rust, Puccinia poarum, may be maintained on its alternate hosts, Tussilago farfara and Poa spp., are described. Telial material collected in the autumn requires extensive washing and drying before teliospores will infect Tussilago, but telial material collected after a winter in the field, in mid-summer or from plants infected in the laboratory do not require this treatment. Infection of Poa pratensis and P. trivialis can readily be achieved from aeciospores or urediospores. Some advantages of this rust for research and teaching are stated.

A spore settling tower for uniform inoculation of leaves with rust urediniospores

Abstract: A spore settling tower, adapted from the one used by E.L. Sharp at Montana State University, was constructed to achieve uniform deposition of urediniospores onto leaf surfaces (figure 1a). With cereals, seedling leaves were fastened, by means of rubber bands at the base and tip, to metal backing plates inserted into the potting medium. Leaves were oriented so that either the upper or lower leaf surface could be inoculated. The pots were placed horizontally onto the rotating turntable of the settling tower. With seedlings such as sunflower and skeleton weed, where leaves are normally oriented in a horizontal position, the upper (adaxial) leaf surface of specific leaves could be inoculated by placing pots in an upright position onto the turntable of the settling tower. To facilitate loading, the turntable and gearbox mechanism was moved outwards from the exposure chamber on sl ide rollers in metal tracks. When the loaded turntable was replaced into the exposure chamber and the loading door closed, the plants were ready to be inoculated. Urediniospores were discharged upwards into the cylindrical tower by means of an air-rifle to which a 0.4 cm diameter tubular metal, 90 degree elbow was attached (figure 1b). A known weight of urediniospores was placed in the elbow and the modified air-rifle was positioned so that the end of the elbow passed through a hole in the centre of an aluminium sliding plate. After spores were discharged, the sliding plate, on which the heavier spore clumps settled, was withdrawn after a predetermined period. The plant material was then exposed to settling spores for a fixed period of time. During the exposure period the turntable was periodically rotated by the mechanical gearbox control. After the required exposure period had elapsed, the sliding plate was replaced, the plants were removed, and placed into a dew chamber to facilitate spore germination and infection. When more than one physiologic race of a given rust was to be used, the settling tower and exposure chamber were washed thoroughly with alcohol between the discharge of different races to prevent interrace contam ination. A series of experiments were made to determ ine the optimal exposure period and the variation in spore deposition onto paraffin coated microscope slides located at different positions on the rotating turntable. Initially 40 mg of urediniospores of Puccinia graminis Pers. f.sp. avenae Erikss. and Henn. were discharged into the settling tower and were allowed to settle for 2, 4, 6 and 8 min. The experiment was repeated 5 times and a total of 240 slides were examined microscopically. When the turntable was rotated 90° every 30 sec. exposure periods of 6 and 8 min., resulted in maximal and most uniform deposition of spores (1,225 urediniospores per cm; range 1117-1308 per em). Consequently a 6 min. exposure period was considered to be most suitable for P. graminis avenae. It was found that most of the larger spore clumps had settled onto the aluminium sliding plate within 10 seconds after spore discharge. .. . An experiment was made to determine the relationship between the density of urediniospores deposited onto leaves and the weight of urediniospores discharged into the settling tower. The lower (abaxial) surfaces of seedling oat leaves (cv. Algerian) were exposed for 6 min. to 10, 20, 30 and 40 mg of urediniospores of P. graminis avenae. Leaves were subsequently prepared for microscopic examination by a whole leaf clearing and staining technique (2). The experiment was replicated 4 times. The number of spores deposited per cm 2 of leaf surface was 59.5 (range 56-63); 101 (range 95-107), 153 (range 143-162), and 204 (range 195-212) for the 10, 20, 30 and 40 mg spole load respectively. The results showed that there was a variation of about +: 8 percent in the number of spores deposited in each replicate. The results reported in this study appear to be less variable than those reported by others (1) using spore settling towers. Although more sophisticated methods of controlling the density of inoculation deposited on leaves have been used by some workers, the settling tower and airrifle method of discharging spores seems to be satisfactory provided periodic checks are made to ensure that the mechanism of the air-rifle has not deteriorated. The lower spore densities found on leaf surfaces compared with paraffin coated microscope sl ides was related to two factors. Firstly it was found that urediniospores were dislodged from inoculated leaves in transit from the settling tower to the dew chamber and secondly, some spores were removed from the leaf surface during preparation for examination by the whole leaf clearing and staining method. However, despite' these losses of spores, the method di~ enabl~ a relatively uniform and reproducible means of inoculating leaves with rust urediniospores. The authors are indebted to Mr. D.J. Clark for constructing the settling tower discussed in this paper. Readers Spore settling tower showing seedling cereal leaves attached to metal backing plate. Modified air-rifle with metal elbow attachment. (b) Figure 1 (a)

Effects of ozone on bean rust Uromyces phaseoli

Abstract: Diurnal exposure to ozone at low concentrations reduces the size of primary uredia of bean rust on bush bean, increases their number, and leads to secondary pustule formation. Infection does not protect the host tissues from ozone injury, since such injury can be observed immediately adjacent to pustules. Similarly, infection does not retard the enhanced rate of senescence induced by ozone treatment.

Rust preventative coating for metallic surfaces consisting of water-soluble resin and sodium benzoate-potassium tripolyphosphate rust inhibitor

Abstract: A rust preventative for ferrous surfaces comprises by weight from 15 to 75% of phosphoric acid, from 5 to 25% of a water soluble resin, from 5 to 20% of a rust inhibitor wherein the rust inhibitor contains from 25 to 95% of sodium benzoate and from 5 to 75% of potassium chromate, potassium dichromate or potassium tripolyphosphate, from 1 to 10% of a wetting agent and an amount of water to bring the total amount of ingredients to 100%.

Poplar rust in Oueensland

Abstract: The poplar rust fungus Melampsora medusae Thum. previously reported from New South Wales (2) and Victoria (1) was first found at Beerwah in late December, 1972. The disease appears confined to the south-east having been recorded also on unidentified deciduous Populus spp. in Brisbane and Stanthorpe and on four semi-evergreen poplars growing in trial plots in the Warwick Forestry District. Its semi-evergreen hosts are Populus deltoides Marsh var. angulata Sarg. x P.nigra L. var. italica Duroi cv. \"persistante\" from Beerwah and Warwick; and P. monilifera Ait. x P.yunnanensis Dode, P.monilifera x P.nigra var. italica cv. \"persistante\", and P.nigra var. italica c.v \"persistante\" from Warwick. Observations made in forestry plots from December 1972 to early November 1973 indicated the disease had little effect on growth and vigour of these semi-evergreen hosts. Infection was very light from December to late April, and no noticeable defoliation and very little leaf chlorosis had occurred. Only moderate disease occurred after late autumn and much of the foliage was still green, although infected, just prior to abscission in late August. New growth was only lightly infected at age three months. New infections occurred on all semi-evergreen hosts throughout the period of observation. No stages of rust other than uredinia were found. New growth became infected during the 3-4 week period in August when the previous season's foliage was still on the tree. The hyperparasite Eudarluca caricis (Fr.) O. Erikss. has been found in uredinia of M.medusae at Beerwah and Warwick. Activity was greater at the latter site where over 50 per cent of uredinia were infected in August. In contrast, infection at Beerwah has been less than 1 per cent. The fungus was also collected last February from Guyra in New South Wales (IMI 173316) by a colleague, Dr. D. I. Bevege, Another hyperparasite, Cladosporium sp., also occurred infrequently at Beerwah. Observations on poplar rust in Queensland are continuing. (2)

A variety of Puccinia centaureae on Centaurea diffusa

Abstract: A rust from Krymsk, U.S.S.R., strongly adapted to Centaurea diffusa, has small urediniospores and large teliospores, and is named Puccinia centaureae var. diffusae. It holds promise as a control ag...

Vapor space corrosion inhibited compositions

Abstract: An inhibitor consisting of a mixture of at least one fatty acid amide and of at least one amine salt of a C8-C10 acid has been found to give synergistic vapor space rust inhibition with lubricating oils.

Spore germination and ribosomal activity in the rust fungi. II. Variable properties of ribosomes in the Uredinales

Abstract: The axenic growth of rusts is erratic and characterized by a long lag period before growth is observed. An attempt was made to study the initial phase of the lag period by using spores germinated overnight on water. As part of a study of this lag period, the properties of ribosomes from a range of rust fungi were compared. For this purpose, several enzymatic and physical parameters were determined for ribosomes from uredospores of bean rust ( Uromyces phaseoli ), sunflower rust ( Puccinia helianthi ), wheat stem rust ( P. graminis tritici ) and flax rust ( Melampsora lini ), and aeciospores of pine rust ( Cronartium fusiforme ). Ribosome transferase activity and capacity to bind with polyuridylic acid declined during germination of the bean and sunflower rust spores, but the ribosomes from the other spores remained active during germination. In spite of these differences, the sedimentation constants and buoyant densities of the ribosomes were identical.

Preparation of amides

Abstract: A method for preparing amides by reacting a vicinal nitroketone with ammonia, a primary amine or a secondary amine at a temperature of from about 60 DEG to about 130 DEG C. The amides so prepared are useful as foam stabilizers, waterproofing agents, rust inhibitors, fuel oil additives, antistatic compounds, viscosity controllers, cosmetic components and high-temperature solvents.

Behaviour of Rust and Rusted Steel Surfaces

Abstract: The effect of the presence of rust on steel on its further corrosion during outdoor and laboratory exposure to SO2 has been examined. More aggressive initial conditions favour the formation of non-protective, loose rust which-flakes off from the metal surface and increases the subsequent yearly corrosion values. The initial rust present increases the rate of attack during the first 2–3 months, but there is then a general falling off of the corrosion rate with time. SO2-contaminated rust is able to promote corrosion on clean (rust-free) steel, but the amount of corrosion is not dependent on the amount of SO2 adsorbed by the rust. The order of severity of attack on steel by different electrolytes differs from that caused by rust produced by the same electrolytes. Rust contaminated with FeSO4 or FeCl3 enhances the rusting of steel, whereas rust converters (such as phosphates) have beneficial effects. In the further rusting in SO2 of prerusted steel specimens it was found that the duration.of the pre-...

Breeding oats for high yield and for resistance to crown rust in India

Abstract: The progenies of the crosses Landhafer × Punjab local, ag 331 × Punjab local and Gopher × Curt were studied in relation to their resistance against the most virulent race 227 of crown rust and their yield performance. Landhafer was found to possess one dominant gene for resistance to this race, while the oat cultivar ag 331 had two, Gopher had only one gene for resistance, the expression of which was suppressed by an inherent inhibitory factor. The few selected fixed lines of these crosses were put into multilocational yield trials. All the lines (cultures) of cross ag 331 × Punjab local were resistant to rust. They were superior to Kent by 4–46% in fodder and 2–35% in grain yield. The cultures of the cross Gopher × Curt were superior by 23–49% in fodder and by 9–35% in grain yield to Kent besides being resistant to rust.