Effects of Surfactants and Temperature on Triclopyr Activity in Eupatorium adenophorum

Abstract

The effect of surfactants and temperature on triclopyr (((3, 5, 6-trichloro-2-pyridinyl) oxy) acetic acid) activity in Eupatorium adenophorum Spreng were studied at the Royal Ang Khang Highland Agriculture Research Station, Fang District, Chiangmai and at the Department of Agronomy and Central Laboratory, Kasetsart University, Bangkok, Thailand. Triclopyr plus surfactants at the rate of 0.25% (v/v) controlled E. adenophorum better than triclopyr alone under both field and greenhouse conditions. When comparing the two surfactants used in this experiment, OPEO (octyphenol ethylene oxide), a nonionic surfactant was more effective than SABS (sodium alkyl benzenes sulfonate), an anionic surfactant. At 25 degree C triclopyr plus OPEO provided better control than at 15 degree C. There was a tendency to increase superscript 14 C-triclopyr absorption in plants when applied in combination with OPEO. There was 2-3 times as much superscript 14 C-triclopyr absorped in plants at 25 degree C when compared to 15 degree C in a 12 hours period. Absorbed 14 C-triclopyr translocated up and down to other plant parts of E. adenophorum. The sequence of 14 C-triclopyr accumulation were the treated leaf, parts below the treated leaf, parts above the treated leaf and roots respectively. At 25 degree C, the amount of 14 C-triclopyr found in any plant part was greater than at 15 degree C at both 1 and 5 days after treatment. At 15 degree C or 25 degree C, there was some degradation of 14 C-triclopyr in plant parts below the treated leaf at 5 and 10 days after treatment but no degradation occurred in the other plant parts.