scholarly journals Efficiency of more recent fungicides in control of apple scab and powdery mildew

Pesticidi ◽  
2003 ◽  
Vol 18 (3) ◽  
pp. 175-185 ◽  
Author(s):  
Jelica Balaz ◽  
Tatjana Knezevic
Keyword(s):  
Powdery Mildew ◽  
Disease Control ◽  
Apple Scab ◽  
High Efficacy ◽  
Biological Efficacy ◽  
Time Of Application ◽  
Preventive Activity ◽  
Dmi Fungicides ◽  
New Generation

Apple scab (V. inaequalis) and powdery mildew (P. leucotricha) are most economicaly important diseases of apple. Chemical measures are of the highest importance in controlling these diseases. There is great number of fungicides on the market. Fungicide choice and time of application depend upon mechanism of their action. Experiments on controlling apple scab and powdery mildew are carried out in 1998/99 and 2002. in different locations in Vojvodina. According to the obtained results the highest efficacy in the control of apple scab and powdery mildew have performed pesticides from strobilurin group (Stroby-kresoxim-methyl and Zato 50 WG-trifloxystrobin)as well as fungicides belonging to the new group of fungicides (Clarinet). In the disease control of the apple high efficacy have also performed DMI fungicides such as Score 250-EC (in control of apple scab). Topas-lOOE and Webeton (in control of powder) mildew). Lower efficacy have performed fungicides with preventive activity such as combination of Venturin S-50+Cosan. Unpublished data from previous studies (1995-1997) of the fungicide Chorus (cyprodinil) biological efficacy also suggested that this new generation fungicide from anylopyrimidin group showed better efficacy than fungicides belonging to former DMI fungicides, as well as contact ones.

Managing Powdery Mildew of Cherry in Washington Orchards and Nurseries with Spray Oils

2000 ◽  
Vol 1 (1) ◽  
pp. 2 ◽  
Author(s):  
G. G. Grove ◽  
R. J. Boal ◽  
L. H. Bennett
Keyword(s):  
Powdery Mildew ◽  
Disease Control ◽  
Sweet Cherry ◽  
Primary Concern ◽  
Disease Forecasting ◽  
Development Of Resistance ◽  
Dmi Fungicides ◽  
Forecasting System ◽  
Serious Disease ◽  
Eastern Washington

Powdery mildew of sweet cherry is the most serious disease in irrigated orchards and nurseries of Washington. The fungus infects foliage and fruit, but fruit infections are of primary concern due to the potential for rejection of entire crops. Development of resistance to demethylation inhibiting (DMI) fungicides in the mid-1990s increased the difficulty in controlling this disease. Orchard mildew management programs that utilize oils, DMI and strobilurin fungicides have been developed for use in eastern Washington. A growth stage (phenology)/calendar-based program provides excellent disease control, utilizes three fungicidal modes of action, and minimizes oil-induced fruit and foliar phytotoxicity by limiting oil use to no later than the pit hardening stage. A second approach that utilizes oils in a temperature-based disease forecasting system provides excellent disease control with fewer fungicide applications. Accepted for publication 19 July 2000. Published 28 July 2000.

Optimizing Use of DMI Fungicides for Management of Apple Powdery Mildew Caused by Podosphaera leucotricha in New York State

Plant Disease ◽  
2021 ◽  
Author(s):  
David Strickland ◽  
Sara M. Villani ◽  
Kerik Cox
Keyword(s):  
New York ◽  
Powdery Mildew ◽  
Disease Control ◽  
Disease Incidence ◽  
New York State ◽  
Optimal Timing ◽  
Fresh Market ◽  
Podosphaera Leucotricha ◽  
York State ◽  
Dmi Fungicides

Powdery mildew, caused by the ascomycete Podosphaera leucotricha, is an endemic disease found wherever apples are grown that negatively impacts both tree vigor and fresh market yield. In the absence of durable host resistance, chemical management is the primary means of disease control. Demethylation inhibitor (DMI) fungicides are widely used to manage apple powdery mildew, but members within this fungicide class have been observed to differ in efficacy with respect to disease control. Moreover, debate exists as to the optimal timing of DMI fungicide applications for management of apple powdery mildew. In this regard, the goal of this study was to determine the best-use practices for DMI fungicides to manage apple powdery mildew in New York State. Multi-year trials were conducted to evaluate the potential differential efficacy performance of four common DMI fungicides, as well as additional trials to assess optimal application timing. In all years, we observed that treatments of flutriafol and myclobutanil consistently had the lowest incidences of powdery mildew compared to difenoconazole and fenbuconazole. In the 2018 and 2021 trials, the newly registered mefentrifluconazole was more comparable to the difenoconazole program with respect to powdery mildew disease incidence. We hypothesize that differences in DMI efficacy may be due to each fungicides’ water solubility and lipophilicity characteristics, and thus their ability to move systemically in the host or more easily penetrate the surface of germinating conidia. Applications timed between petal fall and first cover resulted in the lowest incidence of powdery mildew on terminal leaves of apple shoots compared to applications timed prior to petal fall. These observations are contrary to previous studies conducted in regions with differing climates. We also found that the incidence of secondary powdery mildew observed two weeks after petal fall was influenced by applications of DMI fungicides during the previous season. For example, management programs consisting of applications of flutriafol or myclobutanil in the prior season tended to have lower incidence of apple powdery in the following spring, presumably owing to reductions in overwintering inoculum. Despite reports of DMI resistance in other apple pathosystems, the DMI fungicide class is still relevant for the successful management of apple powdery mildew in New York State.

scholarly journals Fungicide Resistance Evolving in Ramularia Collo-Cygni Population in Estonia

2021 ◽  
Vol 9 (7) ◽  
pp. 1514
Author(s):  
Riinu Kiiker ◽  
Marite Juurik ◽  
Andres Mäe
Keyword(s):  
Disease Control ◽  
High Resistance ◽  
Fungicide Resistance ◽  
Spring Barley ◽  
Point Mutations ◽  
Ramularia Leaf Spot ◽  
Entire Collection ◽  
Dmi Fungicides ◽  
Fungicide Target ◽  
Succinate Dehydrogenase Inhibitors

Ramularia leaf spot caused by the fungus Ramularia collo-cygni, has recently become widespread in Estonian barley fields. Currently, disease control in barley fields relies on SDHI and DMI fungicides, which might be threatened by R. collo-cygni isolates that are well-adapted to fungicide pressure. In a two-year study, 353 R. collo-cygni isolates were collected from spring barley fields in Estonia. A total of 153 R. collo-cygni isolates were examined for sensitivity to azoles (DMIs; prothioconazole-desthio, epoxiconazole, mefentrifluconazole) and succinate dehydrogenase inhibitors (SDHIs; boscalid, fluxapyroxad). Epoxiconazole was the least effective and a new fungicide mefentrifluconazole was the most effective DMI. Among SDHIs, fluxapyroxad was more effective than boscalid. Also, single R. collo-cygni isolates with high resistance to tested fungicides occurred, which could affect fungicide control of the pathogen. The entire collection of R. collo-cygni was analysed for mutations in fungicide target proteins. Six mutations were identified in CYP51 gene, the most dominant being I381T, I384T, and S459C. Also, numerous point mutations in the SdhC gene were present. The mutation G143A in strobilurin target protein CytB dominates in over 80% of the R. collo-cygni population, confirming the low efficacy of strobilurin fungicides in barley disease control.

scholarly journals Effect of late summer treatments by strobilurines on storage diseases of apples

2006 ◽  
Vol 54 (4) ◽  
pp. 39-44 ◽  
Author(s):  
Pavel Minář
Keyword(s):  
Czech Republic ◽  
Fruit Quality ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Field Tests ◽  
Late Summer ◽  
The Czech Republic ◽  
Storage Diseases ◽  
Biological Efficacy ◽  
Weight Decrease

Biological efficacy of strobilurines (trifloxystrobin and kresoxim-methyl) was evaluated to compare the effect of late treatments of apples against post-harvest diseases with the effect of widely used reference products (captan, tolylfluanid, dithianone, dodine). One treatment 3–4 weeks before the harvest was applied (1000 l/ha water). Tested and reference products were used in doses authorised in the Czech Republic against the apple scab (Venturia inaequalis). Strobilurines effectiveness overcame all the products compared and showed an effect on reduction of weight decrease during the storage. In total 8 field tests were performed in 2000–2004 were efficacy, effect on fruit quality and weight decrease during storage was assessed.

scholarly journals Evaluation of gooseberry cultivars resistance to the American gooseberry powdery mildew Sphaerotheca mors uvae Schwein and its chemical control

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 583-587
Author(s):  
M. Vaverka ◽  
S. Vaverka
Keyword(s):  
Biological Activity ◽  
Czech Republic ◽  
Powdery Mildew ◽  
Chemical Control ◽  
Biological Effect ◽  
Field Trials ◽  
The Czech Republic ◽  
Biological Efficacy ◽  
Extensive Field ◽  
Susceptibility Evaluation

In the course of 1993–2001 extensive field trials were carried out to evaluate the resistance (susceptibility) level of 34 gooseberry cultivars to the American gooseberry powdery mildew Sphaerotheca mors uvae Schwein. Cultivars originated from the Czech Republic and from other European countries. Each tested cultivar had 7 trees (5–10 years old). Beside the resistance (susceptibility) evaluation, biological efficacy of 9 fungicides using EPPO methods has been checked at the same number of cultivars and at the same number of gooseberry trees. Highly significant differences of resistance or susceptibility were observed among gooseberry varieties. Analogical results (differences in biological activity of fungicides) have been attained in the course of chemical treatment. 18 cultivars has been classified as low resistant, 12 cultivars as moderate resistant and 4 cultivars as high resistant. None of the tested fungicides proved perfect biological efficacy (100% healthy berries). 4 of them proved high biological effect (more than 90% healthy berries), 3 proved low biological activity (less than 75% healthy berries) and 2 proved moderate biological activity (75–90% healthy berries).

New tools for studying epidemiology and resistance of grape powdery mildew to DMI fungicides

1997 ◽  
Vol 51 (3) ◽  
pp. 309-314 ◽  
Author(s):  
Christophe Délye ◽  
Frédéric Laigret ◽  
Marie-France Corio-Costet
Keyword(s):  
Powdery Mildew ◽  
Dmi Fungicides ◽  
Grape Powdery Mildew

Breeding Elite Lines of Apple Carrying Pyramided Homozygous Resistance Genes Against Apple Scab and Resistance Against Powdery Mildew and Fire Blight

2015 ◽  
Vol 33 (5) ◽  
pp. 1573-1583 ◽  
Author(s):  
Isabelle O. Baumgartner ◽  
Andrea Patocchi ◽  
Jürg E. Frey ◽  
Andreas Peil ◽  
Markus Kellerhals
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Fire Blight ◽  
Apple Scab

scholarly journals Geostatistical Analysis of the Spatiotemporal Dynamics of Powdery Mildew and Leaf Rust in Wheat

2009 ◽  
Vol 99 (8) ◽  
pp. 974-984 ◽  
Author(s):  
Jonas Franke ◽  
Steffen Gebhardt ◽  
Gunter Menz ◽  
Hans-Peter Helfrich
Keyword(s):  
Spatial Analysis ◽  
Powdery Mildew ◽  
Disease Control ◽  
Leaf Rust ◽  
Temporal Dynamics ◽  
Growth Parameters ◽  
Spatiotemporal Dynamics ◽  
High Variability ◽  
Plant Diseases ◽  
Disease Spread

Plant diseases are dynamic systems that progress or regress in spatial and temporal dimensions. Site-specific or temporally optimized disease control requires profound knowledge about the development of each stressor. The spatiotemporal dynamics of leaf rust (Puccinia recondite f. sp. tritici) and powdery mildew (Blumeria graminis f. sp. tritici) in wheat was analyzed in order to evaluate typical species-dependent characteristics of disease spread. During two growing seasons, severity data and other relevant plant growth parameters were collected in wheat fields. Spatial characteristics of both diseases were assessed by cluster analyses using spatial analysis by distance indices, whereas the temporal epidemic trends were assessed using statistical parameters. Multivariate statistics were used to identify parameters suitable for characterizing disease trends into four classes of temporal dynamics. The results of the spatial analysis showed that both diseases generally occurred in patches but a differentiation between the diseases by their spatial patterns and spread was not possible. In contrast, temporal characteristics allowed for a differentiation of the diseases, due to the fact that a typical trend was found for leaf rust which differed from the trend of powdery mildew. Therefore, these trends suggested a high potential for temporally optimized disease control. Precise powdery mildew control would be more complicated due to the observed high variability in spatial and temporal dynamics. The general results suggest that, in spite of the high variability in spatiotemporal dynamics, disease control that is optimized in space and time is generally possible but requires consideration of disease- and case-dependent characteristics.

scholarly journals Effects of an Apple Scab-Resistant Cultivar on Use Patterns of Inorganic and Organic Fungicides and Economics of Disease Control

Plant Disease ◽  
1998 ◽  
Vol 82 (4) ◽  
pp. 428-433 ◽  
Author(s):  
M. A. Ellis ◽  
D. C. Ferree ◽  
R. C. Funt ◽  
L. V. Madden
Keyword(s):  
Disease Control ◽  
Apple Scab ◽  
Farm Size ◽  
Total Treatment Cost ◽  
Total Cost ◽  
Use Patterns ◽  
Sooty Blotch ◽  
Scab Control ◽  
Total Treatment ◽  
The Cost

An inorganic (sulfur) and a conventional organic fungicide spray program were evaluated on an apple scab-resistant (Liberty) and a scab-susceptible (McIntosh) cultivar for control of scab and for cost effectiveness. Trees of both cultivars were either nontreated, treated with inorganic fungicides only, or treated with a conventional fungicide program. McIntosh trees received full-season fungicide applications and Liberty trees received only the summer cover sprays (after petal fall) for control of summer diseases. In 1991, the number of fungicide applications ranged from 0 for nontreated Liberty to 12 for the full-schedule inorganic program on McIntosh, with both treatments providing excellent scab control. All nontreated McIntosh fruit were unmarketable due to scab infection. Due to a dry growing season and lack of summer disease development, nontreated Liberty fruit was of high quality. In 1992, the number of fungicide applications ranged from 0 for nontreated Liberty to 14 for the full-schedule inorganic treatment on McIntosh, with both treatments providing good to excellent disease control. Results were very similar in 1993. Scab incidence was low for all treatments except the nonsprayed McIntosh over all years. Over 3 years of testing, the conventional fungicide program resulted in an average of 9 and 5 applications per year for McIntosh and Liberty, respectively, compared to 12.6 and 7 applications, respectively, for the inorganic fungicide program. The large reduction in the number of sprays for both programs was due to the elimination of all pre-petal-fall applications on Liberty; post-petal-fall applications are needed to control summer diseases such as flyspeck and sooty blotch. An economic analysis for total cost of fungicide applications for each spray program and cultivar was conducted for hypothetical 4.0-, 8.1- and 16.2-ha farms. Regardless of farm size, the cost of fungicides per ha varied among treatments and cultivars. The inorganic and conventional spray program for McIntosh had similar total costs. On Liberty, the inorganic and conventional programs had 73 and 57% less total cost, respectively, than on McIntosh. Fungicides for the conventional program on Liberty were 1.45 times more costly per ha than fungicides in the inorganic program, but the inorganic program required more applications, resulting in a small difference in total treatment cost per ha.

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