Behaviour of some pesticides in a nutrient-film and in a rock-wool system

Adsorption of ethoprophos, tetrachlorvinphos and etridiazole onto rock-wool was found to be much weaker than adsorption onto soils. The rates of transformation in water and in water plus rock-wool at 20°C were low. The concentration of etridiazole was measured in a nutrient-film system with recirculating nutrient solution. The decrease was rapid in the first few hours but was more gradual afterwards, to low values at 8 days after application. Etridiazole penetrated poorly into the lower part of a rock-wool system when the solution was trickled near the stem-base of the tomato plants.