A Comparison of Crop Loss Models

Madden, L. V.; Pennypacker, S. P.; Kingsolver, C. H.

doi:10.1111/j.1439-0434.1981.tb03340.x

Cited by 12 publications

(3 citation statements)

References 6 publications

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“…The raw severity data (72 data sets per assessment date and canopy layer) were averaged per plot for each assessment date and canopy layer and these were used to establish a relationship between disease severity and seed yield. To develop yield loss models, the severity data were analysed using the most commonly used groups of disease-yield models (Zadoks & Schein, 1979;Madden et al, 1981;Sache & Zadoks, 1994;Madden & Nutter, 1995). These included (1) critical point models, which relate yield to severity at a single assessment date; (2) multiple point models, which relate yield to disease severities at more than one assessment date; and (3) AUDPC models, which relate yield to AUDPC.…”

Section: Methodsmentioning

confidence: 99%

Yield loss of lentil caused byUromyces viciae-fabae

Negussie

Pretorius

2008

South African Journal of Plant and Soil

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Yield loss in lentil (Lens culinaris Medik.) due to rust (Uromyces viciae-fabae [Pers.] J. Schröt) was determined by assessing crop and disease parameters at different growth stages and leaf canopy layers in field epidemics at Akaki, Ethiopia. The epidemics were created by inoculation of the rust-susceptible cultivar EL-142 with U. viciae-fabae and spraying plots with tebuconazole at different frequencies. The epidemics produced disease progress curves that varied significantly in the rate (r L ) of temporal progression and area under the disease progress curve (AUDPC). The rust epidemic, in particular between early flowering and early pod formation, had a significant influence on seed yield, pods per plant and seed mass. Mean seed yield losses up to 41.6% were recorded. The number of seeds per pod remained unaffected by the disease. The effect of rust on seed yield of lentil can be predicted with AUDPC and critical-point models using disease severity assessed on the upper canopy layer in the early flowering stage. Every 1% increase in rust severity reduced seed yield by 8.4%. Rust severity ≥ 4.7% at the critical early flowering stage significantly reduced seed yield, and hence, any measure that keeps severity below this threshold level would be advisable.

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Section: Methodsmentioning

confidence: 99%

Yield loss of lentil caused byUromyces viciae-fabae

Negussie

Pretorius

2008

South African Journal of Plant and Soil

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“…The Weibull model described well (Madden et al, 1981;Sinha & Varma, 2004) most of the registered epidemics, with R 2 higher than 0.85 (Figure 1). However, there were differences in apparent infection rates, due to the treatments, only in the vegetative flushes 1 and 3 (Table 3).…”

Section: Resultsmentioning

confidence: 55%

Epidemiology and strategies for chemical management of powdery mildew in mango

Pérez-Rodríguez

Monteón-Ojeda

Mora-Aguilera

et al. 2017

Pesq. agropec. bras.

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-The objective of this work was to evaluate phytosanitary strategies for the chemical control of powdery mildew (Oidium mangiferae) in mango, based on the alternation of active ingredients with different modes and sites of action, and to determine the environmental and epidemiological conditions that favor the development of the disease. The experiment was conducted in Guerrero, México, in commercial orchards, within a program for the development of fungicide spraying strategies. Epidemic curves were used on temporal analyses of the disease for: incidence; area under disease progression curve (AUDPC); severity; and conidial seasonality and its relationships with meteorological parameters. The disease was better controlled with the application of systemic fungicide followed by contact fungicide with multisite activity. The first symptoms appeared 30 days after the issuance of shoots, and the most susceptible phenological (critical) stages were at full bloom and at the onset of fruit with 8-15 mm. Optimum conditions for the development of powdery mildew, which maximizes the density of airborne spores, are temperatures higher than 30°C and relative humidity over 90%.Index terms: Mangifera indica, Oidium mangiferae, epidemics, fungicide resistance, integrated pest management, multisite fungicides. Epidemiologia e estratégias para o manejo químico do míldio-pulverulento em mangueiraResumo -O objetivo deste trabalho foi avaliar estratégias fitossanitárias para o controle químico do míldio-da-mangueira (Oidium mangiferae), baseadas na alternação de princípios ativos com diferentes modos e sítios de ação, e determinar as condições ambientais e epidemiológicas que favorecem o desenvolvimento da doença. O experimento foi realizado em Guerrero, México, em pomares comerciais, no âmbito de um programa para o desenvolvimento de estratégias de pulverização com fungicida. Curvas epidêmicas foram utilizadas em análises temporais da doença quanto à: incidência; área abaixo da curva de progresso da doença (AACPD); severidade; e sazonalidade dos conídios e sua relação com parâmetros meteorológicos. A doença foi mais bem controlada com a aplicação de fungicida sistêmico seguido de fungicida de contato, com atividade multissítio. Os primeiros sintomas apareceram 30 dias após a emissão dos brotos, e os estádios fenológicos mais sensíveis (críticos) foram o de floração completa e o de frutos com 8-15 mm. As condições ótimas para o desenvolvimento do oídio, que maximizam a densidade de esporos no ar, são temperatura acima de 30°C e umidade relativa superior a 90%.Termos para indexação: Mangifera indica, Oidium mangiferae, epidemia, resistência a fungicidas, manejo integrado de pragas, fungicidas multilocais.

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“…Therefore, they recommended models that varied from simulation of crop loss at a regional scale to simulations intended to influence management strategies. Madden et al (1981) compiled several studies to build a general statistical model of crop loss due to plant diseases, the simplicity of which allowed for a comparison of losses due to different diseases. However, their model does not quantify disease effects, which would be necessary to examine the effects of annual weather series on the value of different control strategies.…”

Section: Introductionmentioning

confidence: 99%