A new approach for control of Azolla filiculoides.
Kerosene mixed with the surfactants calcium dodecylbenzene sulphonate and dodecylhexaethoxylate at a range of concentrations up to 10% was applied as 10- mu l droplets to floating A. filiculoides. The droplets spread over the surface in direct proportion to the surfactant concentration; kerosene alone covered 0.18 m2 while 10% calcium dodecylbenzene sulphonate increased the spread by over 100 times to 18.9 m2. The herbicide is highly selective against azolla in rice. Controlled nutrient release from nitrogen-rich A. filiculoides is now possible, enabling its wider use as a controlled green manure for paddy rice fields. From summary.