Most formulants and adjuvants are low molecular weight solutes, and they have the potential to be sorbed in the plant surface and deeper layers of the cuticle. This can have a huge impact on the sorption potential of actives and their mobility in the rate limiting barrier of the cuticle. Factors including volatility, photostability, plant compatibility, selectivity, salt compatibility, rainfastness, speed of action, weed control, residual efficacy, and the possible product combinations often depend primarily on the relative sorption and penetration and interaction of active and adjuvant. However, many factors affect the manifestation of these positive effects in practice like separation of active and adjuvant from the respective dispersion during evaporation, unmatched speed of penetration, or precipitation of active or adjuvant. Typically, adjuvants have several functions, and ignoring wetting effects here, they can act in the dry spray deposit as much as in the cuticle, for example they can solubilize actives in the former and mobilize them in the latter. For best results, a timely and rate fit is needed that is robust enough to withstand practical variability. Successful commercial formulations show a perfect match of active(s) penetration and adjuvant non-penetration. Three extreme examples will be shown for a model leaf cuticle system, and another extreme and striking example will be given that shows that plant structure can change the picture completely. The latter is a missed cause for the difficulty of proper product optimisation under field and particularly greenhouse conditions.

Co-penetration of actives and adjuvants and its significance for the matched pair liaison

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.