Leaching of methomyl from undisturbed cores of two Australian soils was investigated. With the volume of water and the rate of leaching used, only a small percentage (<10%) of methomyl applied was leached. More than half of the methomyl (50 to 58%) was retained in the cores after 3 weeks. This portion of methomyl would be available for root uptake by tobacco plants, since adsorption of methomyl onto soil colloids occurs to a small extent only. About 34 to 43% of methomyl applied was lost in 3 weeks, probably by transformation and volatilization. However, fast root uptake of methomyl by tobacco plants (within one day after application) reported previously would ensure sufficient systemic level of methomyl for the control of Tobacco Yellow Dwarf.

(Full article published with kind permission from "Tobacco International")