SEDL / STP / STP1112-EB / STP16872S

Temperature-Activated Release of Trifluralin and Diazinon

Carter, DH
project leaderformulation chemistDirector, Agricultural Products of Landec Labs, Inc., Menlo Park, California94025

Meyers, PA
project leaderformulation chemistDirector, Agricultural Products of Landec Labs, Inc., Menlo Park, California94025

Greene, CL
project leaderformulation chemistDirector, Agricultural Products of Landec Labs, Inc., Menlo Park, California94025

Pages: 13    Published: Jan 1992

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Abstract

Landec Labs has been developing a family of polymers (Intelimer^™) that when used in encapsulation, respond to a temperature change by releasing active ingredient (AI). Microcapsules made from these polymers containing selected pesticides have been developed which utilize this “off” and turn “on” property. Below the temperature of interest, the microcapsules have low release of the AI thereby protecting it from leaching and degradation. At the temperature of interest, the microcapsules have a higher release of the active ingredient. The change in release rate in response to temperature is unique to microcapsules made from Intelimer polymers and is not observed with commercial microcapsules. A variety of active ingredients including trifluralin and diazinon have been successfully microencapsulated using Intelimer polymers. Greenhouse and field studies indicate the microencapsulated trifluralin had reduced phytotoxicity to corn. In a cotton field trial, trifluralin microcapsules at a 0.55 kg AI/ha rate provided equivalent 90 day control of weeds to a 1.1 kg AI/ha treatment of Treflan 4EC^™. Greenhouse results have demonstrated the temperature-activation characteristics with trifluralin and diazinon. The efficacy of diazinon capsules (made with Intelimer polymers) on corn root worm also will be discussed.