Crop Oil Concentrates Comparison: Connecting Chemical Features to Performance

Abstract

Adjuvants are used in or associated with agrochemical formulations in tank mixtures to improve and ensure the performance of active ingredients during crop management. They can modify physicochemical properties, improving the spray solution quality and stability. Adjuvants are able to improve properties such as wettability, adhesion, and spreading of spray droplets, thus contributing to better retention, persistence, and absorption/penetration of the active ingredient into the target species. As a result, an increase in productivity for the farmer can be expected. One of the most common types of adjuvants used to enhance pesticide performance is the oil-based emulsion, commonly known as crop oil concentrate. The oil component of crop oil concentrates can be derived from either mineral oil (petroleum oil concentrate) or soybean/vegetable oil (methylated seed oil). These products also contain an emulsifier system to achieve the emulsion stability necessary upon dilution for application in the spray tank. In recent years, high-load surfactant oil concentrates have been formulated that increase the functions available from the product. Four different oil concentrates were tank mixed with herbicides and fungicides and compared with regard to the following aspects of their physicochemical characterization: static and dynamic surface tension, contact angle on flat and tilted surface, emulsion stability, and adhesion. The spray droplet size distribution and drift potential were also evaluated. Some mathematical correlations were used to estimate spreading and retention. Field trials were conducted with fungicide (strobilurin and triazole mixture) and also with different herbicide combinations (glyphosate tank mixed with tembotrione and glyphosate tank mixed with clethodim). From these studies, this paper tries to connect chemical formulation features to performance results.