Showing papers on "Rust published in 1979"

Physical model for steel corrosion in concrete sea structures­ theory

Abstract: A physical-mathematical model is developed for concrete exposed to sea water. The model describes: (1)Diffusion of oxygen, chloride ions, and pore water through the concrete cover of reinforcement; (2)ferrous hydroxide near steel surface; (3)the depassivation of steel due to critical chloride ion concentration; (4)the cathodic and anodic electric potentials depending on oxygen and ferrous hydroxide concentrations according to Nernst equation; (5)the polarization of electrodes due to changes in concentration of oxygen and ferrous hydroxide; (6)the flow of electric current through the electrolyte in pores of concrete; (7)the mass sinks or sources of oxygen, ferrous hydroxide, and hydrated red rust electrodes, based on Faraday law; and (8)the rust production rate, based on reaction kinetics. To enable calculations, numerical values of all coefficients are indicated. The theory is completed by formulating the problem as an initial-boundary value problem.

Effect of rust (Phakopsora pachyrhizi) on soybean yield and quality in south-eastern Queensland

Abstract: In a field trial conducted at the University of Queensland Research Farm, Redland Bay in 1976, plots of soybeans were protected from rust, Phakopsora pachyrhizi, with mancozeb sprays for varying periods after sowing. Seed yield losses were 60-70% in the most severely rusted plots. In a glasshouse trial, rust inoculations were commenced at regular intervals during growth, and yield was reduced by 95% in plants inoculated immediately prior to flowering. In both trials, reduced yield was associated with reductions in the number of filled pods per plant, the number of filled seeds per plant and seed weight. The oil but not the protein content of the seed was also reduced in the more severely rusted treatments in the field trial.

Adult-plant leaf rust resistance in pi 250413, an introduction of common wheat

Abstract: The genetics of adult-plant resistance to leaf rust (Puccinia recondita Rob. ex. Desm.) was studied in a common wheat (Triticum aestivum L.) introduction PI 250413, originally collected in Pakistan. The resistance, although variable in expression, was conditioned bx a single recessive gene not previously identified, which was inherited independently of Lr12, Lr13 and Lr22, three previously identified genes for adult-plant leaf rust resistance. The gene present in PI 250413 was also found in five introductions from Iraq.

The effect of temperature on development of soybean rust (Phakopsora pachyrhizi)

Abstract: Uredospore survival and the development of soybean rust were examined across a range of temperatures. To determine the effect of temperature on uredospore survival, samples of dry uredospores were exposed to each of a series of eight temperatures for 8 h prior to a germination test on water agar at 21°C for 4 or 16 h. Germination was significantly reduced when uredospores had been exposed to temperatures of 28.5–42.5°C. Development of rust in soybeans was examined under four temperature regimes. Following inoculation with uredospores, plant foliage was sprayed with water and kept under conditions of dew at 21°C for 16 h. Plants were then placed in a selected regime. The 17–27°C regime provided the best conditions for rust development. These findings may partially explain some of the observations on rust occurrence in the field.

Spatial and Temporal Spread of Oat Crown Rust

Abstract: BERGER, R. D., and H. H. LUKE. 1979. Spatial and temporal spread of oat crown rust. Phytopathology 69:1199-1201. The spread of oat crown rust (caused by Puccinia coronata) in time and 0.9, 0.4, and 0.35 m/day for cultivars Fulghum, Burt, and Red space was measured equally well by disease severity assessed on whole Rustproof-14, respectively. The rate of isopath movement also was used to plants or on the leaf below the flag leaf (F-I) for cultivars Fulghum measure interplot interference. On Red Rustproof-14, isopath movement (susceptible) and Burt (intermediate). The assessment of leaf F-I on increased from 0.2 to 1.2 m/day when secondary foci enlarged. Rust cultivar Red Rustproof-14 (resistant) underestimated the total proportion increased equally fast (as measured by r) at centers and peripheries of foci. of disease (x). The average apparent infection rates (r) for rust on whole There was no flattening of disease gradients for Burt or Fulghum when logit plants of Fulghum and Burt were 0.4, and 0.35 units per day, respectively. x was plotted against logio d (distance). The logio x versus logio d These rates were significantly faster than that for Red Rustproof-14 (r = transformation for disease gradients provided an aberration of true 0.2). Rust isopaths spread outward from plot centers at rates that averaged gradients, Additional key words: Avena byzantina, disease gradients, epidemiology, isopaths, Puccinia coronata, slow rusting resistance. Disease progress is generally measured as rate of change over strip between columns. A single plot of each cultivar also was time (12). Variation in levels of disease from a source is usually grown 5 km away. These latter three plots were separated from each expressed as a gradient in space (3). In the time function, Van der other by a 15.2-m cultivated strip. They were considered to be Plank (12) used r = (l/ t) [logit (X2) logit (xI) ] in which r is the \"partially isolated reference plots\" and data from them were used to average apparent infection rate, t is time in the interval between X, assess interplot interference in the Latin square plots. Stakes were and X2 (disease proportions), and logit x = loge (xl [1 -x]). Growth placed in all plots in transects oriented in four compass directions functions other than the logistic transformation may be more (NE, NW, SE, and SW) to mark data collection points. The points suitable to express epidemic rates for certain epidemics (1,2). For were 1.22, 2.44, and 4.88 m from the plot center; each plot therefore the spread of disease in space, Gregory (3) advised that logio x be had a total of 12 data collection points. plotted against logio d (d = distance unit) to define the gradients. To initiate the epidemics, 1-mo-old, infected Fulghum plants MacKenzie (10) suggested that both infection rate and gradient be were transplanted in the center of each plot on 6 March 1978 used to characterize slow rusting components. However, (considered day 0). The last leaf (flag) wasjust visible but still rolled MacKenzie found no significant differences among gradients for up in the whorl for plants in the plots. The source plants had been susceptible and slow rusting wheat cultivars, even though there grown in the greenhouse in 15.2-cm diameter clay pots, three to were significant differences in infection rates of the causative four plants per pot. The plants were uniformly inoculated in a fungus, Puccinia graminis f. sp. tritici. settling tower and provided with a 14-hr moisture period in a dew The objective of this study was to characterize the spread of chamber. Numerous sporulating pustules were present on these crown rust (Puccinia coronata Cda. f. sp. avenae Fraser & Led.) on source plants when the plants were positioned in the plots on day 0. oats (Avena byzantina K.) in time and space. The amount of disease on all source plants on day 0 was approximately equal. These source plants remained in the plots for the duration of the experiment. MATERIALS AND METHODS Disease severity was assessed independently by two individuals on each sampling date. One person estimated disease severity on Three oat cultivars with different degrees of horizontal resistance whole plants at each data collection point, the other individual (slow rusting) to crown rust (8,9) were planted. Red Rustproof-14 estimated disease severity on the leaf immediately below the flag (CI 4876) is a resistant, late-maturing cultivar that was selected leaf (leaf F-I) on each of three plants from each collection point. In from Red Rustproof around 1865. Burt (CI 824) is an early epidemic stages, both persons estimated the number of intermediately resistant, early maturing cultivar selected from Red pustules (per plant or per F1 leaf). In later epidemic stages, both Rustproof around 1878. Fulghum (CI 708) is a susceptible, early persons used the Horsfall-Barratt rating scale (4), modified by maturing cultivar selected from Red Rustproof around 1897 (11). within-class integration to obtain more accurate intraclass ratings None of the cultivars has vertical resistance (8) against known races (R.D. Berger, unpublished). The ratings included all chlorosis and of P. coronata f. sp. avenae. necrosis associated with the disease. Disease ratings were begun on Seed of the three cultivars were planted at 3.3 g/m with a funnel 30 March (day 24) and continued at 3or 4-day intervals until 25 seeder in rows 30.5 cm apart. Red Rustproof-14 was planted 1 mo April (day 50). earlier (25 October 1977) than Burt and Fulghum (29 November The average apparent infection rates were calculated as 1977) to synchronize maturities. The plots were square, and described by Van der Plank (12). Disease gradients were obtained measured 7.6 m on a side. The plot design was 3 X 3 Latin square by plotting logit x vs. logiod(d= meters). The rate of disease spread with a 1.2-m cultivated strip between rows (of plots) and a 0.9-m in space was calculated from plotted logit lines for disease observed at 1.22 and 4.88 m from the plot centers for four time periods. The 00031-949X/79/000213$03.00/0 interlinear distance (3.66 m) was divided by the number of days @1979 The American Phytopathological Society needed for disease at 1.22 m to reach the same severity at 4.88 m. Vol. 69, No. 11, 1979 1199 RESULTS Fulghum was not always significantly greater than that on Burt. Red Rustproof-14 (resistant) always had the lowest disease Comparison of disease assessment methods. Estimatesof disease severity. Both Fulghum and Burt had significantly more (P = 0.05) severity on leaf F-I were not significantly different (P= 0.05) from disease than Red Rustproof-14 on all 'sampling dates. independent estimates of disease on whole plants for Fulghum and Cultivar differences in susceptibility also could be detected by Burt. However, the disease estimates on leaf F-I of Red comparing the respective infection rates (Fig. IA, B). The infection Rustproof-14 always were significantly lower (P = 0.05) than rate was highest for the susceptible Fulghum, intermediate for disease estimates for whole plants of this cultivar (Fig. I A, B). Burt, and lowest for the resistant Red Rustproof-14. The infection The average apparent infection rates for rust calculated from rate was significantly lower (P= 0.05) for Red Rustproof14 than disease estimates on Whole plants and on leaf F-I were, for Burt and Fulghum; the rates for Burt and Fulghum were not respectively, r = 0.40 and 0.35 units per day for Fulghum and r = significantly different. The significance of these differences in 0.35 and 0.33 for Burt. The difference in rates measured by either of disease severity and infection rates among cultivars was similar for the assessment methods was not significant (P = 0.05) for both both assessment methods. cultivars. On Red Rustproof-14, the apparent infection rate for Directional gradient. Rust developed more rapidly northeast of disease estimated on leaf F-i (r =0.08) was significantly lower (P= the initial focus in all plots and more slowly to the southwest. This 0.05) than that estimated on whole plants (r = 0.20). directional gradient was most noticeable on the intermediately For Fulghum and Burt, the amount of disease assessed on leaf susceptible cultivar, Burt. The directional gradient on the FI was proportional and representative of the total disease on the susceptible Fulghum was largely obliterated toward the season's whole plant, so either method of estimation validly assessed disease end by the rapid development of rust. The slower development of severity at each sampling site. On Red Rustproof-14, rust rust on Red Rustproof-14 did not exhibit much directional effect. proceeded more slowly from basal leaves to the upper leaves. The directional gradient was measured equally by either assessment Therefore, the assessment of disease on leaf F-1 on Red method. Wind direction information for the plot area was not Rustproof-14 significantly underestimated disease for the whole available to allow correlation of specific wind conditions with plant and for the plot. disease spread. Cultivars and disease severity. Fulghum (susceptible) always had Disease gradients. Crown rust developed at approximately the the highest disease severity of the three cultivars, but severity on same infection rate at all sampled distances from the initial focus in Fulghum and Burt; ie, the logistically transformed disease progress curves for whole plants at each distance were essentially parallel for the respective cultivars (Fig. 2A, B). Therefore, the disease gradient A B observed for any date on Fulghum or Burt was representative of the 4 A-FULGHUM A gradient at most other dates (Fig. 3A, B). For Red Rustproof-14 in *-a BURT the later stages of the epidemic, disease development in secondary *--.E RUST foci intensified, which caused some flattening of the gradient (Figs. .PROOF RUcS 2-C and 3-C). These secondary foci were distinct in the Red . PROOFRustproof14 plots. The foci w

Identification of the gene for adult-plant leaf rust resistance in thatcher

Abstract: The gene for adult-plant resistance to race 9 of leaf rust (Puccinia recondita Rob. ex. Desm.) in the common wheat cultivar Thatcher (Triticum aestivum L.) was allelic to Lr22a, a gene for adult-plant leaf rust resistance previously transferred to hexaploid wheat from Aegilops squarrosa L. This gene, designated Lr22b, was linked with Tg, a gene for tenacious glumes, and W21, an inhibitor of waxy foliage, both known to be on chromosome arm 2Dα and linked with Lr22a.

Mode of parasitism of a mycoparasite, Cladosporium gallicola, on western gall rust, Endocronartium harknessii

Abstract: (1979). Mode of parasitism of a mycoparasite, Cladosporium gallicola, on western gall rust, Endocronartium harknessii. Canadian Journal of Plant Pathology: Vol. 1, No. 1, pp. 31-36.

Protective gun cover

Abstract: To protect the finish of hand guns, rifles and firearms from rust and corrosion, a fabric cover is provided having an interior pile facing which is treated with a petroleum distillate mixture having metal protecting qualities. The fabric cover is capable of breathing. The cover can be used as a lining for a gun storage case or holster.

Atmospheric corrosion rates, time‐of‐wetness and relative humidity

Abstract: The effect of relative humidity (RH) on atmospheric corrosion rates r has been studied in laboratory experiments for rust covered steel in air and air + 1 ppm SO2. The expression: describes the experimental results, where rcrit is the corrosion rate at the critical relative humidity RHcrit and b″ is the normalized corrosion rate at RH = 100%. While a large effect of NaCl impurities in rust was found, no effect of SO2 was observed. Time-of-wetness was determined in outdoor exposure using the previously described atmospheric corrosion monitor (ACM). It was found that for exposure at a site in Thousand Oaks, California, the time-of-wetness corresponds to RH > 40%.

Effect of Citrus Rust Mite Damage on Citrus Fruit Growth

Abstract: Weight per fruit at harvest was negatively correlated with damage by Phyllocoptruta oleivora (Ashmead) for ‘Valencia’ and ‘Pineapple’ oranges and for ‘Duncan’ grapefruit. For all 3 varieties, soluble solids and % acid were positively correlated with citrus rust mite damage. The transverse diameters of Duncan grapefruit with the same initial diam and different amounts of citrus rust mite damage were found to diverge with time. Damaged fruit grew slower, and its final diam was less than that for undamaged fruit. The amount of rust mite damage (D) (% of surface), (t) (day of the year) and diam (d) (cm) of Duncan grapefruit were related by d = (24.5/(D−105.5) + 10.6)/(1 + exp(aD−bt)) where aD is given by aD= bto + In (kD/ko(1 + exp (ao−bto))−1). kD, the final diam (cm) of fruit with D% of the surface damaged is given by kD = 24.5/(D−105.5) + 10.6. to is the day of the year at which the damage occurred, and ao and b are constants to be determined from the growth of undamaged fruit.

Rust-preventing agent for aqueous systems and rust-inhibiting lubricating compositions

Abstract: Rust-inhibiting compounds, especially for aqueous systems such as tool-lubricating emulsions for machine tools and which consist of amine salts of a number of monoaminoalkylene dicarboxylic acids are disclosed. These rust-inhibitors are used in combination with water and an alkanolamine. Examples and test results are given.

Multiline cultivars--how their resistance influence leaf rust diseases in wheat.

Abstract: To understand how multiline cultivars of wheat develop better protection against leaf rust, seven experimental multilines with 0, 28, 40, 50, 58, 60 and 70% susceptibility were subjected to leaf rust epiphytotics in the field along with their pure line components. A mixture comprising 12 leaf rust races, 10, 11, 12, 17, 20, 63, 77, 106, 107, 108, 162 and 162 A was used. Both the initial inoculum (Xo) and rate of increase (r) of leaf rust were substantially reduced in the multiline cultivars. Xo was reduced by 45–75% and the over-all infection rate (r) by as much as 16% over the average of components. As a result of reduced Xo and r, the intensity of leaf rust in the multilines was also significantly affected at all stages of rust development. It was reduced from 32,10 to 89.54% over the average of components differing from one multiline to another and also from time to time. The susceptible recurrent parent, Kalyansona at the peak period of rust infection exhibited 86.75% severity while in the multilines it ranged from 5.80 to 35%. The rate of increase in the multilines was found to be proportional to the logarithm of the proportion of susceptible plants in the host mixture. Further, it was found that even if as many as 50% susceptible plants are present in a multiline they would not suffer much from leaf rust damage.

Lubricating oil compositions

Abstract: LUBRICATING OIL COMPOSITION A lubricating oil composition of improved rust inhibitory capability contains a small amount of the sulfate of an oxyalkylenated alcohol or phenol having a molecular weight of about 500-5,000.

Rust preventive agent

Abstract: PURPOSE: To obtain an excellent rust preventive agent for steel products, by adding maleic acid, 1-phenylthio urea, alkyldimethyl benzylammonium chloride or the like in a specified amount to a specified amount of phosphoric acid which functions as the main component. CONSTITUTION: This antirust preventive agent is composed of 160W600 phosphoric acid, 0W13 maleic acid, 0.5W5 1-phenylthiourea, 1W15 alkyldimethyl benzylammonium chloride, 1W10 polyoxyethylene alkylphenylether, and 10W40 isopropyl alcohol respectively in terms of the content g number per liter. The metallic salt of zinc, aluminum and nickel can be added furthermore by an amount of 1W20g/l as the film forming agent. Such rust preventive agent is applied to the steel products by coating, spraying and soaking to obtain a clean surface of the steel product without any smut. COPYRIGHT: (C)1981,JPO&Japio

Environmental effects on inoculum quality of dormant rust uredospores

Abstract: WIESE, M. V., and A. V. RAVENSCROFT. 1979. Environmental effects on inoculum quality of dormant rust uredospores. Phytopathology 69:11061108. Uredospores of Puccinia graminis f. sp. tritici and P. recondita f. sp. germination and infectivity were reduced or eliminated by increased tritici, fungi which cause stem rust and leaf rust of wheat, respectively, were treatment temperatures, especially above 25 C. Germinability and especially produced in the greenhouse on wheat seedlings (Triticum aestivum 'Little infectivity further were reduced by exposure to 100% RH. Supplemental Club'). Newly harvested, mature, dormant uredospores immediately were light reduced or eliminated the detrimental effects of high RH, but subjected to specific light, temperature, and relative humidity (RH) otherwise caused no measurable effect. Reductions in infections per leaf treatments for 24 and 48 hr, then tested for germinability and infectivity, and in infection efficiency always were proportionally greater than were Compared with untreated spores, which consistently germinated >91% and losses in germinability. The possible epidemiological significance of these which produced 60 ± 20 infections per leaf in standardized tests, findings is discussed. Additional key words: spore germination, epidemiology. Uredospores of wheat rust fungi are the principal inoculum that MATERIALS AND METHODS contributes to rust epidemics. Their production, dispersal, and Procedures previously used for studies of germinability (15-17) germination, along with host penetration and infection comprise were extended to incorporate measurements of infectivity. an important cycle of events in the development of rust diseases Uredospores of stem rust (Puccinia graminis f. sp. tritici) race 56 (Fig. 1). Each of these events is affected by environmental variables and leaf rust (P. recondita f. sp. tritici) race 2 were produced on that can limit the rate and extent of disease development and, seedlings of wheat (Triticum aestivum L. 'Little Club'). Newly therefore, each is an important quantitative parameter in produced spores were harvested and immediately separated into 3 conceptual models of the initiation and progress of disease. to 5 ± 0.01-mg lots. The conditions for spore treatment were as In nature, the rate of completion of the uredospore cycle is described (15,16) except that the weighed spore lots were dispersed regulated by physical and biological variables; principally on 10 X 10-mm glass planchets and incandescent light was temperature, moisture, light, and the host-parasite relationship. unfiltered and fixed at 22,630 Ix. The environmental variables that accompany and influence Measurements of spore performance were made at the time of the various cycle events have been studied extensively (1,3, spore collection and after treatment. In all cases, the germinability 5,7,9-14,17). Attention also has been given to environments and infectivity of treated spores was compared with that of that reduce uredospore viability or regulate their subsequent untreated spores from the same collection held at ambient RH at 4 performance (5,7,9,10,15-17). For example, hydration (exC in the dark for the duration of the treatment period (15-17). posure of dormant spores to humid atmospheres) promotes the After environmental treatment, each spore lot was added to subsequent germination of old spores (7,9,14-17) but induces a Mobilsol 100 (13), and the suspension was adjusted to 1 mg spores light-sensitive inhibition of the germination of newly produced per milliliter. One-tenth milliliter aliquots of this suspension were spores (15-17). Evidence also is accumulating which suggessts that quantitatively atomized onto groups of 10 first leaves of wheat the performance of spores as inoculum may reflect the specific hostseedlings and onto duplicate strips of newly-prepared 1% water parasite relationship that regulated their production (M. V. Wiese, agar. unpublished and W. A. Shipton, James Cook Univ., North Queensland, Australia, personal communication). Such studies demonstrate environmental variables that regulate subsequent uredospore performance and, perhaps, the resultant epidemic. Disease cannot occur unless some portion of the inoculumr LIBERATION population is infectious. However, uredospore inoculum, a parameter of prime importance to disease development, normally SPORULATION is described only in quantitative terms (2,4,6,8). The inoculum/ quality of the spores is either assumed to be constant or / unknown. (NO ENVIRONMENTAL UREDOSPORE RELOCATION • VARIABLES In earlier studies, the germinability of mature dormant INFECTION HOST CYCLE uredospores exposed to various temperature, light, and RH N HOST regimes has been described (15-17). The objective of the present study was to measure the influence of the same or similar postproduction-pregermination environments on the performance of uredospores as inoculum (Fig. 1). Such assessments of PENETRATION inoculum quality could be used to improve conceptual models ofI (WATER) disease development that presently only account for inoculum MONITOR [-TION

Rust preventing treatment of metal-plated steel materials

Abstract: A rust preventing treatment for a metal-plated steel product which comprises treating the metal-plated steel product with an aqueous solution containing 0.01% to 10% by weight of tannic acid on the basis of the aqueous solution and 0.001% to 10% by weight of a water-soluble or water-dispersible polymer which is stable when mixed with the tannic acid to form a corrosion resistant film on the surface of the metal-plated steel product.