The temporal pattern of captan residues on apple leaves and fruit under field conditions in relation to weather and canopy structure

Xu, Xiangming; Murray, R. A.; Salazar, José Domingo; Hyder, Kieran

doi:10.1002/ps.1527

Cited by 20 publications

(19 citation statements)

References 35 publications

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“…However, this study only considers one zone because we focused on the fruit-to-fruit-variability in residues, measured as VF at each sampling time, which did not differ very much between canopy zones (Xu et al 2007b;Xu et al 2006). Hence all zone-related model aspects are not described further in this article.…”

Section: Brief Description Of the Modelmentioning

confidence: 97%

“…To simulate the effect of heterogeneous factors driving the dissipation, parameters k 1 , k 3 , and k 4 were randomly sampled from an appropriate normal distribution for each sampled fruit on a given day. To output residue concentrations, daily average fruit weight is estimated using a logistic fruit growth model, developed from field data (Xu et al 2007b). This logistic model is not described here because this growth model is not activated in this simulation study; instead fruit weight at a particular time was sampled from a specific normal distribution with its parameters from field data (Xu et al 2007b).…”

Section: Execution Of the Modelmentioning

confidence: 99%

“…To output residue concentrations, daily average fruit weight is estimated using a logistic fruit growth model, developed from field data (Xu et al 2007b). This logistic model is not described here because this growth model is not activated in this simulation study; instead fruit weight at a particular time was sampled from a specific normal distribution with its parameters from field data (Xu et al 2007b). Finally the model presents predicted residues in the form of both total residues per fruit (µg/fruit) and residue concentrations (µg/g).…”

Section: Execution Of the Modelmentioning

confidence: 99%

See 2 more Smart Citations

Investigating Factors Affecting Unit-to-Unit Variability in Non-Systemic Pesticide Residues by Stochastic Simulation Modelling

Huo

Salazar³

et al. 2008

Human and Ecological Risk Assessment: An International Journal

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The estimation of acute dietary intake plays a key role in the safety assessment of pesticide residues and needs knowledge of the unit-to-unit variability in residues. There is limited knowledge of contributions of factors to often observed large unit-tounit variability in residues. A stochastic simulation study was conducted to investigate the effects of sample size and heterogeneity in factors driving residue dissipation of non-systemic pesticides on the unit-to-unit variability among individual apples. The heterogeneity in driving factors was expressed in terms of variability in three dissipation parameters. The variability factor (VF), calculated as the ratio of residues in individual fruit at the 97.5th percentile and the mean residue, was used to represent the unit-to-unit variability. As the rate of dissipation increased, the variability in the corresponding parameter led to larger increases in the variability VF of residues over time. Thus, under field conditions, the relative in pesticide residues is expected to increase with time although the absolute level of residues decreases. The coefficient of variation (CV) was used to describe residue variability in samples of small sizes (5, 10, 20, 40, and 80). When sample size was fewer than 40 fruit, the sample CV increased steeply with decreasing sample size. Measuring residues as concentrations, instead of per fruit, also led to an average 4-8% increase in the CV of residues because of variability in fruit expansion.

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Section: Brief Description Of the Modelmentioning

confidence: 97%

Section: Execution Of the Modelmentioning

confidence: 99%

Section: Execution Of the Modelmentioning

confidence: 99%

See 1 more Smart Citation

Investigating Factors Affecting Unit-to-Unit Variability in Non-Systemic Pesticide Residues by Stochastic Simulation Modelling

Huo

Salazar³

et al. 2008

Human and Ecological Risk Assessment: An International Journal

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“…The rainfastness and wash-off of pesticides has been examined with several crops including kiwifruit (Gaskin et al, 2013), apple (Hunsche et al, 2011) and grasses such as tall fescue (Lolium Arundinaceum) (Gannon and Yelverton, 2008). Additionally, Xu et al (2007Xu et al ( , 2008 modeled fungicide residues and incorporated the effect of weather conditions on plant diseases and pests. Cu-based formulations had a greater rainfastness and residual activity than organic fungicides in mandarin orchards after both natural and simulated rainfall events (Vicent et al, 2007).…”

Section: Introductionmentioning

confidence: 98%

Modeling raindrop strike performance on copper wash-off from vine leaves

Pérez‐Rodríguez

Gómez

López-Periago

et al. 2015

Journal of Environmental Management

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“…Today, the most common plant protection measure is the application of chemical plant protection products by using air-assisted sprayers. Pesticides are widely used to control pests and diseases of food crops, which may lead to residues in foodstuffs (Xiang-Ming et al, 2008). During the last decade, European countries have launched national initiatives to reduce the use of pesticides.…”

Section: Introductionmentioning

confidence: 99%

Quality and efficiency of apple orchard protection affected by sprayer type and application rate

Sedlar

Bugarin

Nuyttens³

et al. 2013

Span. j. agric. res.

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The goal of this work was to evaluate the potential of reduced application rates in apple trees as well as the potential of selective spray applications by using sensor-based tree detection techniques in Serbian fruit production. Their economical and biological effect was evaluated based on the quality and efficiency of the crop protection and technoeconomic analysis. Results showed that during suitable weather conditions and with properly adjusted sprayer settings, a reduced application rate of 381 L ha -1 gave same quality of crop protection as a medium application rate of 759 L ha -1 . A two-year efficiency trial on Venturia inaequalis and Podosphaera leucitricha infecting apple also showed that there was no significant difference in crop protection results for different types of orchard application techniques and application rates. The techno-economic analysis showed that selective application should be introduced in practice in areas > 3 ha given that the cost of their introduction pays off after 2-3 seasons. Every subsequent season would give a clear economic profit. Besides the economic benefits, selective application technique also has a significant positive ecological effect due to reduction of spray losses and the amount of plant protection products used.

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The temporal pattern of captan residues on apple leaves and fruit under field conditions in relation to weather and canopy structure

Abstract: Captan loss is mainly due to rain, and the loss is negligible under dry conditions.

Cited by 20 publications

References 35 publications

Investigating Factors Affecting Unit-to-Unit Variability in Non-Systemic Pesticide Residues by Stochastic Simulation Modelling

Investigating Factors Affecting Unit-to-Unit Variability in Non-Systemic Pesticide Residues by Stochastic Simulation Modelling

Modeling raindrop strike performance on copper wash-off from vine leaves

Quality and efficiency of apple orchard protection affected by sprayer type and application rate

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