Cuticular uptake of xenobiotics into living plants. part 2: influence of the xenobiotic dose on the uptake of bentazone, epoxiconazole and pyraclostrobin, applied in the presence of various surfactants, into Chenopodium album, Sinapis alba and Triticum aestivum leaves

Abstract

This study has determined the uptake of three pesticides, applied as commercial or model formulations in the presence of a wide range of surfactants, into the leaves of three plant species (bentazone into Chenopodium album L. and Sinapis alba L., epoxiconazole and pyraclostrobin into Triticum aestivum L.). The results have confirmed previous findings that the initial dose (nmol mm(-2)) of xenobiotic applied to plant foliage is a strong, positive determinant of uptake. This held true for all the pesticide formulations studied, although surfactant concentration was found to have an effect. The lower surfactant concentrations studied showed an inferior relationship between the amount of xenobiotic applied and uptake. High molecular mass surfactants also produced much lower uptake than expected from the dose uptake equations in specific situations.

Volatilisation of pesticides under field conditions: inverse modelling and pesticide fate models

“…17,20,76,77 Slow-release formulations inhibit the release of the AI in soil applications, and other formulation components have similar effects that can be modelled.…”

“…surfactants, also increases the uptake by plants. 20 Other formulation components can increase or reduce photodegradation, influencing the amount of AI available for volatilisation. 23 -26 The longevity of pesticides on the crop surface is further affected by the nature and the age of the crop, the stage of development, the characteristics of the leaf surface and the density and height of the canopy.…”

Dose e taxa de aplicação de fungicida no controle da ferrugem da folha (Puccinia triticina) e da mancha amarela (Pyrenophora tritici repentis) do trigo

“…Tais fatores referem-se principalmente às características ligadas à camada da cutícula da epiderme foliar da planta alvo, que é dependente da espécie vegetal e das condições ambientais (FERREIRA, 2002(FERREIRA, , 2003WANG;LIU, 2007;KIRKWOOD, 1999), bem como das características inerentes à tecnologia de aplicação: momento biológico de controle, percentual de cobertura e penetração das gotas pulverizadas no dossel da cultura, propriedades físico-químicas da calda, adjuvantes e ingredientes ativos utilizados, condições metereológicas durante a aplicação, entre outros (FORSTER; ZABKIEWICZ; RIEDERE, 2004;LIU, 2006); KNOCHE et al, 1998;BUKOVAC, 1999BUKOVAC, , 2000WANG;LIU, 2007;KIRKWOOD, 1999).…”

“…A absorção é ampliada pelo aumento da cobertura da gota na superfície vegetal, aumento da concentração dos ingredientes ativos e adjuvantes na calda aplicada (FORSTER; RIEDERE, 2004, FORSTER;LIU, 2006), e pelo uso de massas moleculares menores quando de um mesmo adjuvante (NIELSEN et al, 2005;RIEDERE, 2004). Todavia, características inerentes à espessura e o grau de polaridade da camada de cutícula -dependentes da espécie vegetal da planta alvo e das condições ambientais em que tais plantas se desenvolvem -influenciam diretamente neste processo de absorção (FERREIRA, 2002(FERREIRA, , 2003WANG;LIU, 2007;KIRKWOOD, 1999).…”

Influence of adjuvants on the dissipation of fenpropimorph, pyrimethanil, chlorpyrifos and lindane on the solid/gas interface

“…Additionally, the degradation rate on plant surfaces (photolytic and chemical stability) and the uptake into leaves can influence volatilisation. The effect of pesticide formulations on sorption and uptake has been studied extensively (De Ruiter et al, 2003;Liu, 2004;Forster et al, 2006;Wang and Liu, 2007;Castro et al, 2014). Dissipation from the leaf surface occurs mainly by penetration into the plant, (photo)-degradation and volatilisation (Garau et al, 2002;Carlsen et al, 2006).…”