Control of soilborne pathogens using steam combined with exothermic reaction chemicals (Bioflash system) is widely investigated from 1999, with interesting results considering disease reduction in open field condition against Sclerotinia minor and Sclerotinia sclerotiorum. For improving evidences about treatment’s mechanisms of action, a specially constructed apparatus was built for laboratory analysis on sclerotia. The central body of the apparatus contained a sample drawer and four pipes for dispensing air-steam mixture, and is filled with soil during tests. The drawer, containing three sample holders in which sclerotia are mixed with soil, is equipped with thermal sensors for monitoring temperatures. The four pipes are connected with an external tube that is feeded with a steam generator (0-60 g min-1), while an additional pipe allowed air to be pumped into the system. The apparatus was set for simulating the thermal effects due to a mobile steam generator, at mild, medium or drastic condition, with Tmax of 60, 70 or 100 °C respectively. These temperatures were maintained for 5 min, and followed by a progressive reduction. These treatments were repeated adding calcium oxide (CaO) for evaluating exothermic reactions effects on germination and leakage of S. minor and S. sclerotiorum sclerotia. The results confirmed positive effects of exothermic reactions in disease control. Steam treatments seems to be strongly effective on S. sclerotiorum only at drastic condition, while, adding CaO, the surviving is reduced drastically even with medium treatment (germination about 11%). Even S. minor, more sensitive to steam, was completely controlled with medium treatment using CaO, while mild condition causes a low germination (about 20%).
Effect of exothermic reactions in steaming treatments: trials on sclerotia survival using an ad hoc constructed apparatos
TRIOLO, ENRICO
2007-01-01
Abstract
Control of soilborne pathogens using steam combined with exothermic reaction chemicals (Bioflash system) is widely investigated from 1999, with interesting results considering disease reduction in open field condition against Sclerotinia minor and Sclerotinia sclerotiorum. For improving evidences about treatment’s mechanisms of action, a specially constructed apparatus was built for laboratory analysis on sclerotia. The central body of the apparatus contained a sample drawer and four pipes for dispensing air-steam mixture, and is filled with soil during tests. The drawer, containing three sample holders in which sclerotia are mixed with soil, is equipped with thermal sensors for monitoring temperatures. The four pipes are connected with an external tube that is feeded with a steam generator (0-60 g min-1), while an additional pipe allowed air to be pumped into the system. The apparatus was set for simulating the thermal effects due to a mobile steam generator, at mild, medium or drastic condition, with Tmax of 60, 70 or 100 °C respectively. These temperatures were maintained for 5 min, and followed by a progressive reduction. These treatments were repeated adding calcium oxide (CaO) for evaluating exothermic reactions effects on germination and leakage of S. minor and S. sclerotiorum sclerotia. The results confirmed positive effects of exothermic reactions in disease control. Steam treatments seems to be strongly effective on S. sclerotiorum only at drastic condition, while, adding CaO, the surviving is reduced drastically even with medium treatment (germination about 11%). Even S. minor, more sensitive to steam, was completely controlled with medium treatment using CaO, while mild condition causes a low germination (about 20%).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
