Fungicide resistance management: maximising the effective life of plant protection products

2021 ◽  
Author(s):  
Isabel Corkley ◽  
Bart Fraaije ◽  
Nichola Hawkins
2014 ◽  
Vol 104 (12) ◽  
pp. 1264-1273 ◽  
Author(s):  
Frank van den Bosch ◽  
Neil Paveley ◽  
Femke van den Berg ◽  
Peter Hobbelen ◽  
Richard Oliver

We have reviewed the experimental and modeling evidence on the use of mixtures of fungicides of differing modes of action as a resistance management tactic. The evidence supports the following conclusions. 1. Adding a mixing partner to a fungicide that is at-risk of resistance (without lowering the dose of the at-risk fungicide) reduces the rate of selection for fungicide resistance. This holds for the use of mixing partner fungicides that have either multi-site or single-site modes of action. The resulting predicted increase in the effective life of the at-risk fungicide can be large enough to be of practical relevance. The more effective the mixing partner (due to inherent activity and/or dose), the larger the reduction in selection and the larger the increase in effective life of the at-risk fungicide. 2. Adding a mixing partner while lowering the dose of the at-risk fungicide reduces the selection for fungicide resistance, without compromising effective disease control. The very few studies existing suggest that the reduction in selection is more sensitive to lowering the dose of the at-risk fungicide than to increasing the dose of the mixing partner. 3. Although there are very few studies, the existing evidence suggests that mixing two at-risk fungicides is also a useful resistance management tactic. The aspects that have received too little attention to draw generic conclusions about the effectiveness of fungicide mixtures as resistance management strategies are as follows: (i) the relative effect of the dose of the two mixing partners on selection for fungicide resistance, (ii) the effect of mixing on the effective life of a fungicide (the time from introduction of the fungicide mode of action to the time point where the fungicide can no longer maintain effective disease control), (iii) polygenically determined resistance, (iv) mixtures of two at-risk fungicides, (v) the emergence phase of resistance evolution and the effects of mixtures during this phase, and (vi) monocyclic diseases and nonfoliar diseases. The lack of studies on these aspects of mixture use of fungicides should be a warning against overinterpreting the findings in this review.


2015 ◽  
Vol 76 (2) ◽  
pp. 191-206 ◽  
Author(s):  
Adam Okorski ◽  
Agnieszka Pszczółkowska ◽  
Tomasz Oszako ◽  
Justyna A. Nowakowska ◽  
Małgorzata Oszako

AbstractThe possibility of using chemicals in European forestry is extremely limited due to the binding legal regulations and specific conditions concerning the market of plant protection products. This is reflected in the limited availability of active fungicides in forestry. Due to this limitation, practitioners using fungicides in forest nurseries and forest cultivation must have substantial knowledge of the biology of pathogens to ensure satisfactorily effective protection.The work presented here provides an overview of the currently recommended fungicides in Polish forestry as well as the mechanisms of interaction between the active substances and the pathogen, the plant and mycorrhizal fungi. The risk of fungicide resistance, which has been insufficiently explored in the context of forest pathogens, is also discussed in this paper.


2013 ◽  
Vol 103 (12) ◽  
pp. 1209-1219 ◽  
Author(s):  
F. van den Berg ◽  
F. van den Bosch ◽  
N. D. Paveley

Strategies to slow fungicide resistance evolution often advocate early “prophylactic” fungicide application and avoidance of “curative” treatments where possible. There is little evidence to support such guidance. Fungicide applications are usually timed to maximize the efficiency of disease control during the yield-forming period. This article reports mathematical modeling to explore whether earlier timings might be more beneficial for fungicide resistance management compared with the timings that are optimal for efficacy. There are two key timings for fungicide treatment of winter wheat in the United Kingdom: full emergence of leaf three (counting down the canopy) and full emergence of the flag leaf (leaf 1). These timings (referred to as T1 and T2, respectively) maximize disease control on the upper leaves of the crop canopy that are crucial to yield. A differential equation model was developed to track the dynamics of leaf emergence and senescence, epidemic growth, fungicide efficacy, and selection for a resistant strain. The model represented Zymoseptoria tritici on wheat treated twice at varying spray timings. At all fungicide doses tested, moving one or both of the two sprays earlier than the normal T1 and T2 timings reduced selection but also reduced efficacy. Despite these opposing effects, at a fungicide dose just sufficient to obtain effective control, the T1 and T2 timings optimized fungicide effective life (the number of years that effective control can be maintained). At a higher dose, earlier spray timings maximized effective life but caused some reduction in efficacy, whereas the T1 and T2 timings maximized efficacy but resulted in an effective life 1 year shorter than the maximum achievable.


2020 ◽  
Author(s):  
Maxime Garnault ◽  
Clémentine Duplaix ◽  
Pierre Leroux ◽  
Gilles Couleaud ◽  
Olivier David ◽  
...  

SummaryResearch rationale: In modern cropping systems, the near-universal use of plant protection products selects for resistance in pest populations. The emergence and evolution of this adaptive trait threaten treatment efficacy. We identified determinants of fungicide resistance evolution and quantified their effects at a large spatiotemporal scale.Methods: We focused on Zymoseptoria tritici, which causes leaf blotch in wheat. Phenotypes of qualitative or quantitative resistance to various fungicides were monitored annually, from 2004 to 2017, at about 70 sites throughout 22 regions of France (territorial units of 25 000km2 on average). We modelled changes in resistance frequency with regional anti-Septoria fungicide use, yield losses due to the disease and the regional area under organic wheat.Key results: The major driver of resistance dynamics was fungicide use at the regional scale. We estimated its effect on the increase in resistance and relative apparent fitness of each resistance phenotype. The predictions of the model replicated the spatiotemporal patterns of resistance observed in field populations (R2 from 0.56 to 0.82).Main conclusion: The evolution of fungicide resistance is mainly determined at the regional scale. This study therefore showed that collective management at the regional scale could effectively complete local actions.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 370
Author(s):  
Arkadiusz Artyszak ◽  
Dariusz Gozdowski ◽  
Alicja Siuda

Water shortage and drought are a growing problem in Europe. Therefore, effective methods for limiting its effects are necessary. At the same time, the “field to fork” strategy adopted by the European Commission aims to achieve a significant reduction in the use of plant protection products and fertilizers in the European Union. In an experiment conducted in 2018–2020, the effect of the method of foliar fertilization containing silicon and potassium on the yield and technological quality of sugar beet roots was assessed. The fertilizer was used in seven combinations, differing in the number and time of application. The best results were obtained by treating plants during drought stress. The better soil moisture for the plants, the smaller the pure sugar yield increase was observed. It is difficult to clearly state which combination of silicon and potassium foliar application is optimal, as their effects do not differ greatly.


Author(s):  
Gavin Lewis ◽  
Axel Dinter ◽  
Charlotte Elston ◽  
Michael Thomas Marx ◽  
Christoph Julian Mayer ◽  
...  

2021 ◽  
Author(s):  
Christian J. Kuster ◽  
Nicola J. Hewitt ◽  
Clare Butler Ellis ◽  
Christian Timmermann ◽  
Thomas Anft

Author(s):  
Marco Grella ◽  
Fabrizio Gioelli ◽  
Paolo Marucco ◽  
Ingrid Zwertvaegher ◽  
Eric Mozzanini ◽  
...  

AbstractThe pulse width modulation (PWM) spray system is the most advanced technology to obtain variable rate spray application without varying the operative sprayer parameters (e.g. spray pressure, nozzle size). According to the precision agriculture principles, PWM is the prime technology that allows to spray the required amount where needed without varying the droplet size spectra which benefits both the uniformity of spray quality and the spray drift reduction. However, some concerns related to the effect of on–off solenoid valves and the alternating on/off action of adjacent nozzles on final uneven spray coverage (SC) have arisen. Further evaluations of PWM systems used for spraying 3D crops under field conditions are welcomed. A tower-shaped airblast sprayer equipped with a PWM was tested in a vineyard. Twelve configurations, combining duty cycles (DC: 30, 50, 70, 100%) and forward speeds (FS: 4, 6, 8 km h−1), were tested. Two methodologies, namely field-standardized and real field conditions, were adopted to evaluate the effect of DC and FS on (1) SC variability (CV%) along both the sprayer travel direction and the vertical spray profile using long water sensitive papers (WSP), and (2) SC uniformity (IU, index value) within the canopy at different depths and heights, respectively. Furthermore, the SC (%) and deposit density (Nst, no stains cm−2), determined using short WSP, were used to evaluate the spray application performances taking into account the spray volumes applied. Under field-controlled conditions, the pulsing of the PWM system affects both the SC variability measured along the sprayer travel direction and along the vertical spray profile. In contrast, under real field conditions, the PWM system does not affect the uniformity of SC measured within the canopy. The relationship between SC and Nst allowed identification of the ranges of 200–250 and 300–370 l ha−1 as the most suitable spray volumes to be applied for insecticide and fungicide plant protection products, respectively.


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