Methodology for Determining Foliar Penetration of Herbicides with Reference to Oil-Based Adjuvants

Formulation of phytotoxins fromPhomasp. FGCC#18 for the management ofParthenium hysterophorusL.

“…Traditionally, spray formulations have incorporated petroleum-based oils (Robinson and Nelson 1975), but more recently oils extracted from crop seeds such as soya bean, sunflower, canola and coconut have been used. The role of oils in herbicide application and efficiency has been investigated by several groups (Gauvrit 1994;Foy 1996;Dexter 1998). Crop oil-based Archives of Phytopathology and Plant Protection 1265 adjuvants i.e.…”

Improving agrochemical performance: possible mechanisms for adjuvancy

“…Although this is almost certainly a surface tension effect, such a mechanism has been disputed by some workers (Roggenbuck et al, 1994). Holloway and Stock, 1990, with additional information from Stock et al, 1992;Gauvrit, 1994 andMercier et al, 1997. ) There are also differences in the penetration rates of adjuvant oils following foliar application as diluted ECs or as simple solutions in organic solvents.…”

“…On water-repellent leaves, surface tensions of 2S-30mN/m are required for effective spreading; these values are similar to those necessary for optimal droplet retention (Holloway, 1994). Addition of oil-based adjuvants may also increase droplet spreading on some plant species (Gauvrit, 1994), but they are not as efficient as the best surfactants on waxy plant surfaces. Factors contributing to their performance may also be emulsifier content and the viscosity of the oil used.…”

“…Oil-based adjuvants can also improve the foliar uptake of pesticides, especially herbicides (reviews by Gauvrit and Cabanne, 1993;Gauvrit, 1994;Nalewaja, 1995). Oil composition, emulsifier content and target species all influence enhancement efficiency.…”

Confocal laser scanning microscopy – an attractive tool for studying the uptake of xenobiotics into plant foliage

“…A radiolabelling method is generally used to measure the uptake of pesticides into plant foliage. Uptake is generally defined as the proportion of the radioactive dose not recovered from washing the treated leaves (Gauvrit, 1994). Although this method allows a fast screening of pesticide formulations and tank‐mix additives based on the gross uptake of the active ingredients, it cannot provide information on the location of absorbed chemicals inside leaf tissues and cell compartments.…”