Thermal micro-dosing is a method of weed control in which extremely small doses of very hot vegetable oil are applied to post-emergent weeds in the most weed-challenged areas such as within the seedline of dense crop stands.
Research conducted by UC Davis and funded by the Tomato Research Institute in 2012 successfully demonstrated this technology in tomato fields, with an efficacy of 100% mortality on S. nigrum and A. retroflexus weed species when >90% of their respective leaf surfaces were covered with heated oil.
More recently, research from the University of Bonn-Landtechnik in Germany independently validated the effectiveness of this technique for weed control, in addition to supplementary research which confirmed the rapid mineralization of small quantities of vegetable oil with no adverse impact on soil health.
The reason that thermal micro-dosing works so well is the same reason why hot oil will produce more severe burns than open flames in a kitchen. Heated oil and other sources of “wet heat” such as steam and boiling water impart much more energy than sources of dry heat such as propane burners. This heat energy penetrates the meristematic cells of young weed plants, either killing them outright or severely stunting their growth to allow a competitive crop canopy to form above them.