Chemical control of loose smut (Ustilago segetum var. tritici) of barley and the effects of cultivar and environment on disease incidence

1991 ◽  
Vol 31 (3) ◽  
pp. 373
Author(s):  
R Loughman ◽  
EJ Speijers ◽  
GJ Thomas ◽  
DJ Ballinger
Keyword(s):  
Western Australia ◽  
Chemical Control ◽  
Disease Incidence ◽  
Field Trials ◽  
Loose Smut ◽  
High Rainfall ◽  
Barley Cultivars ◽  
Control Disease ◽  
Moderately Resistant ◽  
Very High

The reasons for an increase in barley loose smut in high rainfall areas of Western Australia were investigated in field trials from 1986 to 1988 by examining the effects of environment, cultivar and adequacy of chemical control. Disease was 4-18 times greater in 2 seed lines produced in very high rainfall areas (>750 mm/year) compared with that produced in high (450-750 mm/year) or low (<325 mm/year) rainfall areas. The effectiveness of 5 fungicide seed treatments was assessed. No fungicide seed treatment controlled disease completely. Triadimenol at 225 mg a.i./kg and carboxin at 940 mg a.i./kg were most effective, providing 93-96% disease control. Treatments were significantly (P<0.01) less effective in high rainfall areas of Western Australia. Barley cultivars released recently in Western Australia were found to be susceptible to loose smut; we suggest that the replacement of the moderately resistant Dampier with these cultivars has contributed to an increased incidence of disease.

scholarly journals SUSCEPTIBILITY OF CHILLI LINES / VARIETIES TOWARDS CHILLI LEAF CURL VIRUS AND ITS MANAGEMENT THROUGH VECTOR CONTROL

2017 ◽  
Vol 29 (1) ◽  
pp. 17 ◽  
Author(s):  
Muhammad S. Hussain ◽  
Khalid Naveed ◽  
Muhammad Atiq
Keyword(s):  
Disease Incidence ◽  
Field Trials ◽  
Local Germplasm ◽  
Moderately Resistant ◽  
Leaf Curl Virus ◽  
Chilli Leaf Curl Virus ◽  
Leaf Curl Disease ◽  
Whitefly Vector ◽  
Susceptible Response ◽  
Leaf Curl

                                                                  Chilli leaf curl virus (ChiLCV) is a serious problem for chilli production in Pakistan and India. In this study, fourteen different chilli lines / varieties were screened for their resistance/susceptibility towards ChiLCV in open field trials. Data of disease severity and disease incidence was recorded on weekly basis. Out of all varieties screened, Tatapuri Chilli and CH111 showed high susceptibility towards the chilli leaf curl disease. Talhari, CH 99, CH103, CH 106, CH107, CH108, CH109, GSL111 showed susceptible response whereas CBS1292 showed moderately susceptible response towards the disease. Only two cultivars Hybrid-46 and Hot Queen were found as moderately resistant. The screening experiment showed that most of the chilli varieties are susceptible to chilli leaf curl disease and resistance is lacking in local germplasm. Furthermore, three insecticides: Imidacloprid, Polo and Emamectin were tested for their efficacy for the management of disease and whitefly vector in field conditions at weekly intervals. Out of three insecticides, Polo gave best results as compared to Emamectin and Imidacloprid against chilli leaf curl disease and whitefly vector.

scholarly journals Identification of Novel Sources of Resistance to Sclerotinia Basal Stalk Rot in South African Sunflower Germplasm

2017 ◽  
Vol 18 (2) ◽  
pp. 87-90 ◽  
Author(s):  
Gerald J. Seiler ◽  
Christopher G. Misar ◽  
Thomas J. Gulya ◽  
William R. Underwood ◽  
Bradley C. Flett ◽  
...  
Keyword(s):  
South African ◽  
Research Council ◽  
Agricultural Research ◽  
Disease Incidence ◽  
Field Trials ◽  
Sources Of Resistance ◽  
Breeding Programs ◽  
Stalk Rot ◽  
Agricultural Research Council ◽  
Moderately Resistant

Sclerotinia basal stalk rot (BSR) is a serious fungal disease that reduces yield of global sunflower (Helianthus annuus L.) production. Because limited chemical and biological controls of BSR are available and the present-day hybrids lack sufficient resistance, identification of new sources of resistance is needed to manage the disease in the future. A total of 59 cultivated oilseed sunflower accessions from the Agricultural Research Council, Grain Crops Institute, Potchefstroom, South Africa sunflower collection were evaluated for resistance to BSR in artificially inoculated field trials. Nine accessions from the South African sunflower collection were identified with a disease incidence less than or equal to the moderately resistant sunflower oilseed hybrid. These lines can be used in breeding programs to introgress the genes for resistance to Sclerotinia BSR into other adapted lines, providing a more efficient, durable, and environmentally friendly host plant resistance.

Relations between stocking rate, environment and scorch disease on grazed subterranean clover pasture in Western Australia

1982 ◽  
Vol 22 (116) ◽  
pp. 182 ◽  
Author(s):  
WK Anderson ◽  
RJ Parkin ◽  
MD Dovey
Keyword(s):  
Western Australia ◽  
Chemical Control ◽  
Dry Matter ◽  
Disease Incidence ◽  
Subterranean Clover ◽  
Stocking Rate ◽  
Disease Symptoms ◽  
Sheep Production ◽  
Stocking Rates ◽  
Clover Scorch

The effects of weather on clover scorch disease caused by Kabatiella caulivora, the effects of the disease on pasture and sheep production, and the effect of sheep stocking rate (6, 8, 10 and 12 sheep/ha) on the disease were studied in a field experiment over three seasons near Albany, Western Australia. Spraying with benlate was used to control clover scorch on some treatments. Mean temperatures during the period when symptoms of the disease increased were in the range 11-17�C. Rainfall was frequent each year during the same period. The rapid increase in disease symptoms was observed when pasture dry matter on offer was approximately 2500 kg/ha. Disease symptoms decreased during a period of water stress of the pasture. Clover scorch disease had no consistent effect on pasture or animal production except that pasture dry matter on offer in spring was reduced in the unsprayed treatments at the lower stocking rates in the second two years. Higher stocking rates (10 and 12 sheep/ha) reduced the level of clover scorch symptoms without the use of chemical control with benlate. At the period of peak scorch symptoms a stocking rate of 10 sheep/ha reduced disease incidence by 20-35% compared with 6 sheep/ha in unsprayed plots. Increased sheep stocking rates are suggested as a possible alternative to chemical control or replacement of susceptible strains of subterranean clover in grazed pasture.

scholarly journals Development of a Weather-Based Advisory Program for Scheduling Fungicide Applications for Control of White Rust of Spinach

Plant Disease ◽  
2003 ◽  
Vol 87 (8) ◽  
pp. 923-928 ◽  
Author(s):  
M. J. Sullivan ◽  
J. P. Damicone ◽  
M. E. Payton
Keyword(s):  
Spinacia Oleracea ◽  
Disease Incidence ◽  
Field Trials ◽  
Control Treatment ◽  
Systemic Fungicide ◽  
Advisory Programs ◽  
Advisory Program ◽  
White Rust ◽  
Control Disease ◽  
Day Program

Weather-based advisory programs were developed and evaluated for timing of fungicide applications to control white rust of spinach (Spinacia oleracea) in three field trials using a susceptible cultivar. The advisory programs were based on previous studies that defined periods of temperature (T) and wetness (relative humidity ≥90%, W) that favored disease development. The protectant fungicides mancozeb or maneb (ethylene bisdithiocarbamates; EBDCs) and the systemic fungicide azoxystrobin were applied after 3, 6, 12, 24, and 36 cumulative hours of wetness weighted by temperature (T*W). T*W programs were compared with an advisory program based on 12 h of continuous wetness (12-h W), a 7-day calendar program, and a nonsprayed control treatment. Except for the 3-h T*W program, the number of fungicide applications per trial was reduced for all advisory programs compared with the 7-day program. Averaged over the three trials, applications were reduced from 2.7 per trial for the 6-h T*W program to 3.7 per trial for the 36-h T*W and the 12-h W programs. For the EBDC fungicides, all advisory programs except the 36-h T*W and 12-h W programs reduced incidence and severity of white rust compared with the nonsprayed control. Disease incidence and severity for the 3-h and 6-h T*W programs did not differ from the 7-day program. Compared with the EBDC fungicides, azoxystrobin resulted in reduced disease incidence for each of the spray programs and reduced disease severity for all spray programs except the 7-day program. For azoxystrobin, all advisory programs reduced disease incidence and severity compared with the nonsprayed control. Incidence and severity of white rust did not differ from the 7-day program for the 3-h, 6-h, and 12-h T*W programs. Based on reductions in the number of fungicide applications and the level of disease control, the 6-h and 12-h T*W programs were most efficient advisory programs for the EBDC fungicides and azoxystrobin, respectively.

scholarly journals Comparison of Soil Insecticides Alone and In Combination With PCNB for Suppression of Southern Stem Rot of Peanut1

1988 ◽  
Vol 15 (1) ◽  
pp. 35-38 ◽  
Author(s):  
A. K. Hagan ◽  
J. R. Weeks ◽  
J. A. McGuire
Keyword(s):  
Disease Incidence ◽  
Sclerotium Rolfsii ◽  
Field Trials ◽  
Disease Suppression ◽  
Stem Rot ◽  
Yield Response ◽  
Control Disease ◽  
Soil Insecticides

Abstract The soil insecticides, chlorpyrifos 15G (2.2 kg a.i./ha), ethoprop 15G (3.3 kg a.i./ha), and fonofos (2.2 kg a.i./ha) were compared with pentachloronitrobenzene (PCNB) 10G (11.2 kg a.i./ha) and PCNB (11.2 kg a.i./ha) + insecticide combinations for suppression of southern stem rot caused by Sclerotium rolfsii on peanut in a series of field trials in 1985, 1986, and 1987 in southeastern Alabama. Stem rot loci counts were reduced each year by chlorpyrifos and two of three years of ethoprop, and fonofos compared to the non-treated control. Disease suppression with chlorpyrifos and ethoprop was similar all three years and two of three years with fonofos to that with the fungicide PCNB. Significant differences (P = 0.05) in yield were noted only in 1986 between each of the soil insecticides and the non-treated control. PCNB and PCNB + insecticide combinations with the exception of PCNB + ethoprop in 1985 significantly increased yields over the non-treated control each year. PCNB + insecticide combinations generally provided better disease suppression and/or yield response than each insecticide but not PCNB applied alone. When data were pooled for all 3 years, all treatments significantly reduced disease incidence and significantly increased yield except fonofos and ethoprop.

scholarly journals Host Resistance and Chemical Control for Management of Sclerotinia Stem Rot of Soybean in Ohio

2017 ◽  
Vol 107 (8) ◽  
pp. 937-949 ◽  
Author(s):  
Jaqueline Huzar-Novakowiski ◽  
Pierce A. Paul ◽  
Anne E. Dorrance
Keyword(s):  
Host Resistance ◽  
Chemical Treatment ◽  
Chemical Control ◽  
Disease Incidence ◽  
Stem Rot ◽  
Sclerotinia Stem Rot ◽  
Chemical Treatments ◽  
Full Flowering ◽  
Untreated Check ◽  
Moderately Resistant

Recent outbreaks of Sclerotinia stem rot (SSR) of soybean in Ohio, along with new fungicides and cultivars with resistance to this disease, have led to a renewed interest in studies to update disease management guidelines. The effect of host resistance (in moderately resistant [MR] and moderately susceptible [MS] cultivars) and chemical control on SSR and yield was evaluated in 12 environments from 2014 to 2016. The chemical treatments evaluated were an untreated check, four fungicides (boscalid, picoxystrobin, pyraclostrobin, and thiophanate-methyl), and one herbicide (lactofen) applied at soybean growth stage R1 (early flowering) alone or at R1 followed by a second application at R2 (full flowering). SSR developed in 6 of 12 environments, with mean disease incidence in the untreated check of 2.5 to 41%. The three environments with high levels of SSR (disease incidence in the untreated check >20%) were used for further statistical analysis. There were significant effects (P < 0.05) of soybean cultivar and chemical treatment on SSR levels. Significantly lower levels of SSR were observed in MR cultivars. Both boscalid and lactofen reduced SSR but did not increase yield. Pyraclostrobin increased SSR compared with the untreated check in the three environments with high levels of disease. In the six fields where SSR did not develop, chemical treatment did not increase yield, nor was the yield from the MR cultivar significantly different from the MS cultivar. For Ohio, MR cultivars alone were effective for management of SSR in soybean fields where this disease has historically occurred.

scholarly journals RELATIONSHIP OF METEOROLOGICAL VARIABLES AND INOCULATION TECHNIQUES CONDUCIVE FOR LOOSE SMUT OF WHEAT DEVLEOPMENT

2017 ◽  
Vol 29 (1) ◽  
pp. 145
Author(s):  
Muhammad Shafiq ◽  
Muhammad A. Khan ◽  
Muhammad Hussain ◽  
Muhammad Sajjad ◽  
Ayaz Farzand ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Disease Development ◽  
Loose Smut ◽  
Average Temperature ◽  
Ustilago Tritici ◽  
Inoculation Techniques ◽  
Integral Role ◽  
Relationship Of ◽  
Moderately Resistant ◽  
The Relationship

Ustilago tritici, a seed borne pathogen, remains dormant in seed embryo and causes loose smut disease. The present study was conducted to evaluate two inoculation methods i.e., dip inoculation and syringe inoculation to find out the better method for efficient and reproducible assessment of disease severity, disease incidence and screening of resistant wheat germplasm. Syringe inoculation was found to be better for the inoculation of heads with higher disease incidence than dip inoculation method. Twenty-seven lines were tested for their resistance against loose smut. Two lines were moderately resistant, nineteen lines susceptible and three lines were highly susceptible. Environmental conditions play an integral role in the development of loose smut disease. The relationship of temperature, humidity and rainfall with loose smut development was studied. An average temperature of 23-27 °C, relative humidity 60-90% and rainfall 0.02-1 mm rainfall were statistically most conducive for disease development. The correlation of environmental factors significantly influenced the disease development.

scholarly journals Minimum number of assessment times to compare chemical control treatments for papaya fruit anthracnose

2004 ◽  
Vol 29 (6) ◽  
pp. 659-662 ◽  
Author(s):  
José R. Liberato ◽  
Cosme D. Cruz ◽  
Joseli S. Tatagiba ◽  
Laércio Zambolim
Keyword(s):  
Chemical Treatment ◽  
Chemical Control ◽  
Carica Papaya ◽  
Colletotrichum Gloeosporioides ◽  
Disease Incidence ◽  
Field Trials ◽  
Published Data ◽  
Treatment Comparison ◽  
Minimum Number ◽  
Control Post

The chemical treatment evaluation in the field to control post-harvest fruit anthracnose (Colletotrichum gloeosporioides) requires a suitable disease incidence assessment on harvested papaya (Carica papaya) fruits. The minimum number of papaya fruit harvests was determined for valid treatment comparison in field trials for anthracnose chemical control. Repeatability analysis was done using previously published data. The coefficient determination (R²) estimate range, using four methods, and based on means of 12 assessment times, was 92.58 < R² < 94.45%. The number of assessment times required for R²=90% varied from seven to nine. The R² values of 85.1 < R² < 91.3% estimated by ANOVA suggested that any seven successive assessment times were sufficient for treatment comparison.

scholarly journals A Peri-Implant Disease Risk Score for Patients with Dental Implants: Validation and the Influence of the Interval between Maintenance Appointments

2019 ◽  
Vol 8 (2) ◽  
pp. 252 ◽  
Author(s):  
Miguel de Araújo Nobre ◽  
Francisco Salvado ◽  
Paulo Nogueira ◽  
Evangelista Rocha ◽  
Peter Ilg ◽  
...  
Keyword(s):  
High Risk ◽  
Risk Score ◽  
Disease Risk ◽  
Disease Incidence ◽  
Risk Groups ◽  
Risk Profile ◽  
Moderate Risk ◽  
C Statistic ◽  
Disease Risk Score ◽  
Very High

Background: There is a need for tools that provide prediction of peri-implant disease. The purpose of this study was to validate a risk score for peri-implant disease and to assess the influence of the recall regimen in disease incidence based on a five-year retrospective cohort. Methods: Three hundred and fifty-three patients with 1238 implants were observed. A risk score was calculated from eight predictors and risk groups were established. Relative risk (RR) was estimated using logistic regression, and the c-statistic was calculated. The effect/impact of the recall regimen (≤ six months; > six months) on the incidence of peri-implant disease was evaluated for a subset of cases and matched controls. The RR and the proportional attributable risk (PAR) were estimated. Results: At baseline, patients fell into the following risk profiles: low-risk (n = 102, 28.9%), moderate-risk (n = 68, 19.3%), high-risk (n = 77, 21.8%), and very high-risk (n = 106, 30%). The incidence of peri-implant disease over five years was 24.1% (n = 85 patients). The RR for the risk groups was 5.52 (c-statistic = 0.858). The RR for a longer recall regimen was 1.06, corresponding to a PAR of 5.87%. Conclusions: The risk score for estimating peri-implant disease was validated and showed very good performance. Maintenance appointments of < six months or > six months did not influence the incidence of peri-implant disease when considering the matching of cases and controls by risk profile.

scholarly journals In-Furrow Applications of Metalaxyl and Phosphite for Control of Pink Rot (Phytophthora erythroseptica) of Potato in New Brunswick, Canada

Plant Disease ◽  
2007 ◽  
Vol 91 (10) ◽  
pp. 1305-1309 ◽  
Author(s):  
Khalil I. Al-Mughrabi ◽  
Rick D. Peters ◽  
H. W. (Bud) Platt ◽  
Gilles Moreau ◽  
Appanna Vikram ◽  
...  
Keyword(s):  
New Brunswick ◽  
Disease Incidence ◽  
Field Trials ◽  
Russet Burbank ◽  
Viable Option ◽  
Potato Plants ◽  
Pink Rot ◽  
Phytophthora Erythroseptica ◽  
Sensitive Isolate ◽  
The Mean

The efficacy of metalaxyl-m (Ridomil Gold 480EC) and phosphite (Phostrol) applied at planting in-furrow against pink rot (Phytophthora erythroseptica) of potato (Solanum tuberosum) ‘Shepody’ and ‘Russet Burbank’ was evaluated in field trials conducted in 2005 and 2006 in Florenceville, New Brunswick, Canada. Inoculum made from a metalaxyl-m-sensitive isolate of P. erythroseptica from New Brunswick was applied either in-furrow as a vermiculite slurry at planting or as a zoospore drench in soils adjacent to potato plants in late August. After harvest, the number and weight of tubers showing pink rot symptoms were assessed and expressed as percentages of the total tuber number and total weight of tubers. Metalaxyl-m applied in-furrow was significantly more effective against pink rot than phosphite. The mean percentage of diseased tubers as a percentage of total tuber weight was 1.5% (2005) and 1.2% (2006) for metalaxyl-m-treated plots and 9.6% (2005) and 2.8% (2006) for phosphite-treated plots, a percentage similar to that obtained in inoculated control plots with no fungicide treatment. The mean percentage of diseased tubers expressed as a percentage of the total number of tubers was 1.7% (2005) and 1.3% (2006) for metalaxyl-m-treated plots and 10.1% (2005) and 3.1% (2006) for phosphite-treated plots. Disease incidence was significantly higher using the late-season inoculation technique (respective means in 2005 and 2006 were 9.9 and 3.8% diseased tubers, by weight, and 10.6 and 3.9%, by number) than with the in-furrow inoculation method (respective means in 2005 and 2006 were 3.3 and 0.7% by weight, and 3.7 and 1.3%, by number). The potato cv. Shepody was significantly more susceptible to pink rot (9.9 and 3.3% diseased tubers, by weight, in 2005 and 2006, respectively, and 10.6 and 3.9%, by number) than Russet Burbank (respective means in 2005 and 2006 were 3.4,% and 1.2%, by weight, and 3.7,% and 1.2%, by number). Our findings indicate that metalaxyl applied in-furrow at planting is a viable option for control of pink rot caused by metalaxyl-sensitive strains of P. erythroseptica, whereas phosphite was ineffective.

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