Cercospora Leaf Spot Of Sugar Beet Research Articles

Deposition aids, nozzle selection and carrier volume on canopy deposition and management of Cercospora leaf spot in sugarbeet (Beta vulgaris L.)

Cercospora leaf spot (CLS; Cercospora beticola Sacc.) is an economically devastating disease of sugarbeet (Beta vulgaris L.) in many regions worldwide. Field experiments evaluated the potential of InterLock deposition aid (MVO) and carrier volumes of 115, 235, 350, and 470 L ha−1 for improved CLS management with mancozeb (Manzate Pro-Stick) under moderate CLS intensity. Adding MVO to mancozeb did not reduce disease accumulation or improve yield or sugar quality more than mancozeb alone. Increased carrier volume did not affect disease progression but had a neutral effect on profit margin. Additional field experiments investigated the effect of MVO on spray deposition by analyzing Rhodamine WT recovery from leaves. Using MVO with mancozeb did not improve canopy deposition compared to mancozeb alone, regardless of the nozzle or carrier volume tested. Canopy deposition was improved using Hardi® ISO injet™ nozzles compared to Teejet® XR110 and Teejet® AI3070® nozzles. A quadratic relationship between dye recovery and carrier volume (R2 = 0.2871 p=<0.0001) was found; applications using a carrier volume of 350 L ha−1 improved deposition compared to 115 and 235 L ha−1. While MVO did not improve CLS management when mixed with Manzate Pro-Stick, nozzle selection did influence canopy deposition, and effects on CLS development require further investigation. In this study, increased carrier volume was not beneficial in limiting disease progress but incurred no economic penalty. Given the generally positive correlation between fungicide efficacy and the quality/degree of spray coverage, increased carrier volume should still be considered a best practice in disease management at the carrier volumes tested.

SeedborneCercospora beticolaCan Initiate Cercospora Leaf Spot from Sugar Beet (Beta vulgaris) Fruit Tissue

Cercospora leaf spot (CLS) is a globally important disease of sugar beet (Beta vulgaris) caused by the fungus Cercospora beticola. Long-distance movement of C. beticola has been indirectly evidenced in recent population genetic studies, suggesting potential dispersal via seed. Commercial sugar beet "seed" consists of the reproductive fruit (true seed surrounded by maternal pericarp tissue) coated in artificial pellet material. In this study, we confirmed the presence of viable C. beticola in sugar beet fruit for 10 of 37 tested seed lots. All isolates harbored the G143A mutation associated with quinone outside inhibitor resistance, and 32 of 38 isolates had reduced demethylation inhibitor sensitivity (EC50 > 1 µg/ml). Planting of commercial sugar beet seed demonstrated the ability of seedborne inoculum to initiate CLS in sugar beet. C. beticola DNA was detected in DNA isolated from xylem sap, suggesting the vascular system is used to systemically colonize the host. We established nuclear ribosomal internal transcribed spacer region amplicon sequencing using the MinION platform to detect fungi in sugar beet fruit. Fungal sequences from 19 different genera were identified from 11 different sugar beet seed lots, but Fusarium, Alternaria, and Cercospora were consistently the three most dominant taxa, comprising an average of 93% relative read abundance over 11 seed lots. We also present evidence that C. beticola resides in the pericarp of sugar beet fruit rather than the true seed. The presence of seedborne inoculum should be considered when implementing integrated disease management strategies for CLS of sugar beet in the future.

Optimizing Cercospora Leaf Spot Control in Table Beet Using Action Thresholds and Disease Forecasting.

Cercospora leaf spot (CLS), caused by the fungus Cercospora beticola, is the dominant foliar disease affecting table-beet production in New York. CLS epidemics occur annually and, if uncontrolled, will rapidly lead to defoliation. In broad-acre production, season-long maintenance of healthy leaves is important to facilitate harvest by top-pulling. Fungicides are the dominant means of CLS control and applications are initiated at an action threshold of 1 CLS lesion/leaf. Regular fungicide application occurs thereafter without regard for scheduling based on weather-based risk. The current action threshold was evaluated with selected fungicides in two replicated field trials. Copper oxychloride + copper hydroxide and propiconazole significantly improved CLS control if initiated prior to infection. Pydiflumetofen + difenoconazole significantly reduced area under the disease progress stairs compared with other fungicides tested and was most efficacious when applications began at 1 CLS lesion/leaf. Six replicated field trials also evaluated the utility of scheduling fungicides on weather-based risk rather than a calendar approach. Two risk thresholds (moderate and high) integrating the accumulation of daily infection values based on temperature and relative humidity from a forecaster for CLS in sugar beet were evaluated. Applications of pydiflumetofen + difenoconazole were reduced from three to two by using the forecaster at either risk threshold compared with calendar applications without affecting CLS control. For propiconazole, the moderate risk threshold provided CLS control equivalent to calendar applications and saved one spray per season. Thus, there was substantial scope to reduce spray frequency by scheduling based on weather-based risk rather than calendar applications. The optimal risk thresholds for pydiflumetofen + difenoconazole and propiconazole were high and moderate, respectively. In these trials, periods of high risk occurred less frequently than moderate risk, increasing the reapplication intervals and, hence, represented a less conservative approach to disease management.

Effect of Interval of Spraying or Volume of Fungicides Used on Cercospora Leaf Spot of Sugarbeet

Effect of Interval of Spraying or Volume of Fungicides Used on Cercospora Leaf Spot of Sugarbeet

Biocontrol Elicited Systemic Resistance in Sugarbeet is Salicylic Acid Independent and NPR1 Dependent

Systemic acquired resistance is an innate defense response in plants to a broad array of pathogens. Salicylic acid (SA) and non-expressor of pathogenesis-related genes1 (NPR1) are key players in systemic acquired resistance. Previously we demonstrated the biological control agent Bacillus mycoides isolate BmJ controls Cercospora leaf spot of sugarbeet through induction of pathogenesis-related (PR) proteins and biphasic hydrogen peroxide production. Both of these factors are associated with SA- and NPR1-dependent resistance induction. Here we show BmJ treatment leads to monomerization of NPR1, a phenomenon observed with activation of defense in Arabidopsis. The identity of the NPR1 monomer was confirmed using MALDI-TOF-MS. In contrast to the Arabidopsis system, monomerization of NPR1 in sugarbeet is not preceded by SA accumulation when triggered by BmJ. The SA levels following BmJ treatment were equivalent with water and Bacillus pumulis isolate BMH5E-33 treatments. BMH5E-33 is a non-inducer of resistance. The timeline of NPR1 activation by BmJ (3 hours post application) coincides with the previously observed secondary burst of hydrogen peroxide elicited in sugarbeet by BmJ treatment. These observations suggest PR-proteins induced by BmJ are induced through a SA-independent, NPR1-dependent pathway similar to that reported for the systemic resistance inducer

Analysis of genotypic diversity inCercospora beticola Sacc. field isolates

Genetic variability and population structure ofCercospora beticola, the causal agent of Cercospora leaf spot in sugarbeet, from four sugarbeet-growing regions of Greece were investigated using growth rate, pathogenicity, and mini- and microsatellite DNA fingerprinting. Mycelial growth and pathogenicity were very diverse within and between groups, and no correlation was found between these features and the geographic origin of the isolates. High diversity was found by micro- and minisatellite fingerprinting, with an average gene diversity of 0.21, and no significant differences among populations. Among the 46 isolates, 45 different genotypes were identified, showing a high degree of genotype diversity. Analysis of the genetic profiles provided no evidence for regional patterns of variation (ΦFST=0.01, P=0.261) and the analysis of molecular variation (AMOVA) revealed that genetic variability was due mainly to variations within (99%) rather than between (1%) populations. Such a low level of genetic differentiation is reflected by a migration rate value Nm of 4.7. The high migration rate cannot be referred to splash dispersed conidia. To justify the absence of a regional structure in these C.beticola populations, we must suppose the existence of a long-distance means of dispersal, such as seed transmission and/or man mediated transmission.

Supervised control of Cercospora leaf spot in sugar beet

Two approaches to supervised control of Cercospora leaf spot (CLS) in sugar beet are outlined, and their yield improving capabilities tested in field trials. One approach is based on action thresholds, which use disease severity assessments to indicate the need for a fungicide application. The second is based on measurements of within-crop temperature and relative humidity, to indicate the need for a fungicide application. Disease incidence (% diseased plants) in fungicide treated plots increased in a similar way to unsprayed plots. Incidence increased for all treatments before disease severity, assessed using the Agronomica scale, increased. There was little effect of fungicide treatments on model parameters for disease incidence and severity curves. However, fungicide treatments reduced disease severity by up to 50% and resulted in significantly higher relative sugar yields than the unsprayed treatment (set at 100%). Relative sugar yields from applying the action threshold for two early sprays (115%) and for both weather-based treatments (119% and 121%) did not differ significantly from the calendar sprayed treatment (119%), saving up to two fungicide applications. Fungicide treatments based on weather conditions delayed the increase in disease incidence, and were applied 1 week before treatments based on the first action threshold. Considering the significantly higher financial returns in 2001 and the positive experience with the weather-based system in 2003 and 2004, we conclude that sugar beet growers in the Netherlands should move towards using supervised control approaches for CLS in sugar beet although some further testing of the weather-based system will be necessary.

Spatial and temporal population dynamics of a phyllosphere colonizing Bacillus subtilis biological control agent of sugar beet cercospora leaf spot

Abstract This study examines the spatial and temporal variation of populations of the biological control agent (BCA) BacB, a Bacillus subtilis isolate, in the field and growth chamber in the presence of the fungus, Cercospora beticola , the causal agent of Cercospora leaf spot of sugarbeet. The use of the selective BCA support substrate β-glucan, applied at 0, 0.5, and 1.0% of the spray solution, did not influence differences in total population numbers (spores + vegetative cells) of a spontaneous rifampicin resistant isolate of BacB (Rif+) over a 14 day spray period. BacB Rif+, applied as a spore formulation, declined from 10,000 CFU/cm 2 on day 0.5–100 CFU/cm 2 on day 14 at the three levels of β-glucan tested. Distribution of BacB Rif+ populations was modeled on a leaf scale, with and without β-glucan. Higher populations of vegetative cells were more likely at 14 days with 1% β-glucan than with 0% β-glucan. BacB populations were more aggregated without β-glucan than with the nutrient substrate. There was no correlation between BacB density and Cercospora leaf spot disease severity, indicating that neither antibiosis nor parasitism is likely an important mechanism of disease control.

CERCOPRI: a forecasting model for primary infections of cercospora leaf spot of sugarbeet1

A computerized model for forecasting the appearance of primary infections of cercospora disease on sugarbeet was worked out using meteorological and epidemiological data collected in the western Po Valley from 1980 to 1989. This program, called CERCOPRI, gives a figure for the current risk of disease appearance, a forecast of the risk on a pre‐established day or a forecast of the day on which risk will reach a pre‐established threshold.

Field Evaluation of Various Fungicides to Control Cercospora Leaf Spot of Sugarbeet, Caused by Benomyl-Resistant Strains

Bluehost - Top rated web hosting provider - Free 1 click installs For blogs, shopping carts, and more. Get a free domain name, real NON-outsourced 24/7 support, and superior speed. web hosting provider php hosting cheap web hosting, Web hosting, domain names, front page hosting, email hosting. We offer affordable hosting, web hosting provider business web hosting, ecommerce hosting, unix hosting. Phone support available, Free Domain, and Free Setup.

Control of Cercospora leaf spot of sugarbeet through aerial application of systemic and surface-protecting fungicides

Control of Cercospora leaf spot of sugarbeet through aerial application of systemic and surface-protecting fungicides

Inheritance of resistance to Cercospora leaf spot in sugarbeet

Bluehost - Top rated web hosting provider - Free 1 click installs For blogs, shopping carts, and more. Get a free domain name, real NON-outsourced 24/7 support, and superior speed. web hosting provider php hosting cheap web hosting, Web hosting, domain names, front page hosting, email hosting. We offer affordable hosting, web hosting provider business web hosting, ecommerce hosting, unix hosting. Phone support available, Free Domain, and Free Setup.

The performance of benzimidazole fungicides in the control of Cercospora leaf spot of sugarbeet

Introduction Thiabendazole and benomyl are systemic fungicides which were found to be effective in controlling leaf spot of sugarbeet, caused by Cercospora beticola Sacc. (1,2,3,6)3. Because these fung­ icides are relatively expensive, the use of minimum doses for ob­ taining disease control is essential. However, the minimuHl efiec­ tlve doses are not yet known. Only some of the fungicides 6eposit­ ed on the leaf is absorbed by it (5). An increase in the absorption rate of streptomycin was induced in Sedum pU1'pureum when leaves were kept wet after its application (4). Hence, the effect of leaf wetting on fungIcide effectiveness was also inclucied in tilis study. While no distinction could be made in the field between dle residual and the systemic activity of the fungicides, in greenhouse experiments the effect of the studied factors was examined main­ lyon aspects expressing the systemic activity of the fungicides.

The Systemic Fungicidal Effect of Benzimidazole Derivatives and Thiophanate Against Cercospora Leaf Spot of Sugarbeet

The Systemic Fungicidal Effect of Benzimidazole Derivatives and Thiophanate Against Cercospora Leaf Spot of Sugarbeet