Fungicide-resistance management would be more effective if principles governing the selection of resistant strains could determined and validated. Such then used to predict whether a proposed change fungicide application program decrease for strains. In this review, we assess principle that appears have good predictive power. The states reducing product coefficient (defined as difference between per capita rate increase sensitive strains) exposure time pathogen reduces resistance. We show...

This paper reviews the evidence relating to question: does risk of fungicide resistance increase or decrease with dose? The development progresses through three key phases. During ‘emergence phase’ resistant strain has arise mutation and invasion. subsequent ‘selection phase’, is present in pathogen population fraction carrying increases due selection pressure caused by fungicide. final phase ‘adjustment’, dose choice may need be changed maintain effective control over a where developed...

Many studies exist about the selection phase of fungicide resistance evolution, where a resistant strain is present in pathogen population and differentially selected for by application fungicides. The emergence evolution - not has to arise through mutation subsequently invade been studied date. Here, we derive model which describes populations crops. There are several important examples single mutation, affecting binding with target protein, shifts sensitivity phenotype such an extent that...

Key weather factors determining the occurrence and severity of powdery mildew yellow rust epidemics on winter wheat were identified. Empirical models formulated to qualitatively predict a damaging epidemic (>5% severity) quantitatively disease given occurred. The data used was from field experiments at 12 locations in UK covering period 1994 2002 with matching stations within 5 km range. Wind December February most influential factor for mildew. Disease best identified by model...

Resistance to antimicrobial drugs allows pathogens survive drug treatment. The time taken for a new resistant mutant reach population size that is unlikely die out by chance called “emergence time.” Prolonging emergence would delay loss of control. We investigate the effect fungicide dose on in fungal plant pathogens. A dynamical model combined with dose-response data Zymoseptoria tritici, an important wheat pathogen. Fungicides suppress sensitive pathogen population. This has two effects....

Abstract The relationship between yield loss and disease severity can differ widely crops. This has given rise to the concept of tolerance, with some crops exhibiting a smaller under than others. Genetic improvement minimise is an attractive goal, as it exerts little or no selection pressure on pathogen populations, could form useful component durable management programmes. However, progress towards this end requires thorough understanding phenotypic traits that influence response disease,...

This study used mathematical modeling to predict whether mixtures of a high-resistance-risk and low-risk fungicide delay selection for resistance against the high-risk fungicide. We winter wheat Mycosphaerella graminicola host–pathogen system as an example, with quinone outside inhibitor chlorothalonil The usefulness mixing strategy was measured “effective life”: number seasons that disease-induced reduction integral canopy green area index during yield forming period could be kept <5%....

BACKGROUND A new fungicide resistance risk assessment method is described, based on traits (of pathogens, fungicides and agronomic systems) that are associated with rapid or slow occurrence of resistance. Candidate tested for their predictive value were those which there was a mechanistic rationale they could be determinants the rate evolution. RESULTS dataset 61 European cases against single-site-acting assembled. For each case, number years from product introduction to first detection (the...

A fungicide resistance model (reported and tested previously) was amended to describe the development of in Mycosphaerella graminicola populations winter wheat (Triticum aestivum) crops two sets fields, connected by spore dispersal. The used evaluate usefulness concurrent, alternating, or mixture use high-resistance-risk fungicides as management strategies. We determined effect on each strategy (i) fitness costs resistance, (ii) partial fungicides, (iii) differences dose-response curves...

Abstract BACKGROUND Insensitivity of Zymoseptoria tritici to demethylation inhibitor (DMI) and quinone outside (QoI) fungicides has been widely reported from laboratory studies, but the relationships between sensitivity phenotype or target site genotype field efficacy remain uncertain. This article reports experiments quantifying dose–response curves, investigates performance in vitro half maximal effective concentration (EC 50 ) values for DMIs, frequency G143A substitution conferring QoI...

Insect management strategies for agricultural crop pests must reduce selection insecticide resistant mutants while providing effective control of the insect pest. One strategy that has long been advocated is application insecticides at maximum permitted dose. This found, under some circumstances, to be able prevent resistance allele frequency from increasing. However this approach may, different lead rapid insecticide. To test when a high dose would an strategy, we present flexible...

Abstract BACKGROUND Identifying robust integrated pest management (IPM) strategies requires the testing of multiple factors at same time and assessing their combined effects e.g., on disease control. This makes field‐based experiments large, resource intensive expensive. Hence, there are limits to number treatment combinations that can be practically tested under field conditions. Taguchi approach design (DOE) or is commonly employed enhance quality industrial products. It uses smaller than...

ABSTRACT Fungicide resistance threatens control of Asian soybean rust ( Phakopsora pachyrhizi ) in Brazilian crops; deployment sound management tactics is crucial to prolong the effective life new fungicides. A key integrated pest (IPM) strategy Brazil delay P . inoculum influx through soybean‐free periods, mandated restrictions on sowing dates. We developed an epidemiological model fungicide evolution explore impact delayed selection for a succinate dehydrogenase inhibitor (SDHI) and...

ABSTRACT Fungicide resistance management principles recommend that farmers avoid splitting the total dose applied of a fungicidal mode action (MoA) across multiple applications per season (‘dose splitting’). However, may sometimes be needed to make another proven tactic—application in mixture with different MoA—practically achievable, especially cases where there are limited MoAs available for disease control. Variable effects on selection have been observed field experiments, and its effect...

For individual varieties, tolerance of septoria leaf blotch was quantified by the slope relationship between disease and yield. Variation in severity associated yield responses were provided across two sites three seasons field experiments. Slopes fitted residual maximum likelihood for contrasting models: (i) a fixed‐effects model, where no prior assumptions made about form variety slopes; (ii) random‐effects deviations slopes away from mean formed normal random population with unknown...

Field trials tested which components of epidemic development Puccinia striiformis , the cause yellow rust, were affected by nitrogen (N) fertilizer applied to winter wheat. Both timing and amount N varied affect canopy size leaf content, provide a supply mobile pathogen, causing fresh uptake after expansion was complete. No control plots. A logistic disease‐progress function fitted disease‐severity data, assessed in absolute units. Leaf area specific (g per m 2 tissue) quantified. Large...

Abstract A model of winter wheat foliar disease is described, parameterised and tested for Septoria tritici (leaf blotch), Puccinia striiformis (yellow rust), Erysiphe graminis (powdery mildew) triticina (brown rust). The estimates disease‐induced green area loss, can be coupled with a canopy model, in order to estimate remaining light‐intercepting tissue hence the capacity resource capture. differs from those reported by other workers three respects. First, variables (such as weather, host...

A method is presented to quantify the net effect of disease management on greenhouse gas (GHG) emissions per hectare crop and tonne produce (grain, animal feed, flour or bioethanol). Calculations were based experimental survey data representative UK wheat production during period 2004–06. Elite cultivars, with contrasting yields levels resistance, compared. Across fungicides increased by an average 1·78 t ha −1 GHG reduced from 386 327 kg CO 2 eq. grain. The amount which yield – hence was...

In the European Union, assessments of resistance risk are required by regulatory authorities for each fungicide product and used to guide extent anti-resistance strategies. This paper reports an evaluation a widely 'risk matrix', determine its predictive value. Sixty-seven unique cases in Europe were identified testing assessment scheme, where case was first occurrence pathogen species against group.In most cases, high-, moderate- low-risk categories fungicide, agronomic systems associated...

Strategies to slow fungicide resistance evolution often advocate early "prophylactic" application and avoidance of "curative" treatments where possible. There is little evidence support such guidance. Fungicide applications are usually timed maximize the efficiency disease control during yield-forming period. This article reports mathematical modeling explore whether earlier timings might be more beneficial for management compared with that optimal efficacy. two key treatment winter wheat in...

All cereal crops engage in arbuscular mycorrhizal symbioses which can have profound, but sometimes deleterious, effects on plant nutrient acquisition and growth. The mechanisms underlying variable responsiveness cereals are not well characterised or understood. Adapting to realise benefits could reduce fertiliser requirements improve crop nutrition where is unavailable. We conducted a phenotype screen wheat (Triticum aestivum L.), using 99 lines of an Avalon × Cadenza doubled-haploid mapping...