Three international symposia on adjuvants and agrichemicals have been held to date (1986, 1989, and 1992). The publications based on the symposia are excellent sources of information. The majority of non-proprietary, published research on adjuvant use with pesticides has focused on herbicides and many 324articles on herbicides and adjuvants have appeared in the literature during 1992–1994. Some topics addressed included: organosilicone surfactants; fertilizer additives; pyrrolidones; effects of various other adjuvants on efficacy, antagonism, uptake, penetration, mobility, and translocation; effects on droplet size, drift and spreading; adjuvant evaporation; bioherbicides; safeners; and guidelines for adjuvant use. The effects of ethylene oxide (EO) content of surfactants and oxyethylene chain lengths were studied. Approximately 36 herbicides, 24 weed species, 18 crops, and numerous adjuvants were involved.
Favorable results were generally achieved with the organosilicone surfactant, Silwet L-77®. Fertilizer additives enhanced the activity of several herbicides and overcame antagonism caused by calcium chloride, sodium bicarbonate, and some herbicides. Pyrrolidones exhibited excellent wetting, low surface tension and low contact angle, and enhanced the performance of herbicides. Positive results were obtained with various other adjuvants in most cases. Nonionic surfactants and crop oil concentrates are the adjuvants most widely used with herbicides.
Agrichemical manufacturers are moving toward recommending specific adjuvants that research has identified as maximizing the efficacy of their products. The use of standardized laboratory procedures for evaluating adjuvants is vital in order to ensure that results are both reproducible and valid.