Fungal decay resistance of wood fumigated with chlorpyrifos

Disinfestation is the main purpose of fumigation and no subsequent and sustained protection for longer duration against risk of attack is afforded. The ideal fumigant is infact, one which leaves treated commodity unchanged in all respect. Although the effectiveness of chlorpyrifos as termiticide has been proven in laboratory and field test studies, no information is available concerning the fumigant action against wood degrading fungi. Chlorpyrifos (O, O-diethyl [3, 5, 6-trichloro-2-pyridyl] phosphorothioate) was evaluated as wood fumigant by soil block bioassay test. Soft wood (Pinus roxburghii) and hard wood (Populus deltoides) blocks fumigated with 5 different concentrations of chlorpyrifos were subjected to wood-decaying fungi, white rot (Trametes versicolor) and brown rot (Oligoporus placentus). Results revealed that 4.9% concentration of chlorpyrifos imparted more than 90% protection to the wood against white and brown rot. Laboratory results showed that chloropyrifos is very effective at all concentrations tested, providing more than 75% protection at lowest concentration tested i.e., 0.9%.