-The effects of the pine-oil-based monoterpene alcohols (Pine-oil), a nonylphenol surfactant and emulsified methylated rapeseed oil (Em-MRO) were evaluated on the dynamic surface tension of water, retention of sprays by oats, contact angle of water drops, and foliar uptake of [ 14 C]2,4-D-dimethylamine into oats. Pine-oil and emulsified pine oil (Em-pine-oil) produced the quickest drop in dynamic surface tension and the highest levels of retention. Pine-oil and Em-pine-oil had a limited effect on the contact angle, whereas the surfactant greatly reduced the contact angle. Thus, the mode of action of monoterpene alcohols on retention proceeded in a different way than the surfactant. Em-MRO did not increase retention but did stimulate foliar uptake. Em-pine-oil at 0.5% (v/v) had little effect on foliar uptake. An emulsified mixture of the Pine-oil and methylated rapeseed oil (Em-pine-oil-MRO) increased both retention and uptake. In the field, the presence of Em-pine-oil in large droplet sprays should reduce atmospheric pollution and the drift of sprays applied under windy conditions. herbicide / adjuvant / pine oil / retention / oats