The customer increasingly requires safer and more convenient pesticide formulations. Emulsifiable concentrates and wettable powders are nowadays viewed less favourably by farmers and registration authorities. Suspension concentrates are now common and water‐dispersible granules and emulsions in water are receiving increasing attention. Capsule suspensions offer both safer and more effective performance in favourable cases. For convenience the farmer requires multi‐component products, either as mixtures of active ingredients, which might be as suspoemulsions, or with built‐in enhancing surfactants and oils. Seed treatments are now required as aqueous suspensions and the seed is increasingly of interest as an eficient carrier for pesticides. Research into biological control agents sets the difficult challenge of formulating these products as viable organisms. Three examples of developments are described. These are the applications of polymeric surfactants for suspension concentrates and suspoemulsions, studies of enhancement of pesticide uptake with surfactants and developments in microencapsulation.

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The influence of a number of commercial nonionic polyoxyethylene surfactants on the foliar penetration and movement of two systemic fungicides, ethirimol and diclobutrazol, was studied in outdoor‐grown wheat plants at different growth stages and post‐treatment temperatures in two consecutive growing seasons. Both fungicides were applied as ca 0·2 μl droplets of aqueous suspension formulations containing 0·5 g litre−1 of 14C‐labelled active ingredient; surfactants were added to these suspensions at concentrations ranging from 0·2‐10 g litre−1. To achieve optimum uptake of each fungicide the use of surfactants with different physicochemical properties was required. For diclobutrazol, a lipophilic compound, uptake of radiolabel was best with surfactants of low mean molar ethylene oxide (E) content (5‐6) but it was necessary to use concentrations of ca 5 g litre−1 to attain this. The surfactant threshold concentration for uptake enhancement of radiolabel from ethirimol formulations (< 2 g litre−1) was much lower than that for diclobutrazol but surfactants with E contents > 10 induced the greatest amount of uptake. For both fungicides, surfactants with an aliphatic alcohol hydrophobe were generally more efficient in promoting their uptake than those with a nonylphenol moiety. The sorbitan‐based surfactant ‘Tween 20’ proved to be an effective adjuvant only for the ethirimol formulation; the uptake enhancing properties of the block copolymer ‘Synperonic PE/F68’ were weak. Uptake performance could not be related to the spreading properties of the respective formulations on the wheat leaf surface or to differences in solubilisation of the two fungicides by the surfactants. Although surfactants could substantially increase the amount of acropetal transport of radiolabel from both fungicides, none of those tested specifically promoted it; a constant proportion of the radioactive dose absorbed by a treated leaf was usually exported away from the site of application. The results are discussed in the light of current theories about the mode of action of surfactants as spray adjuvants.