Solarization of Commercial Peat in Transparent Polyethylene Bags and its Effect on Survival of Some Plant Pathogenic Fungi

Two experiments were held to test the effect of solarizationas a disinfestation non-chemical method of peat moss, a potentialsource of pathogenic fungal inocula. Solarization took place in springand summer, 2004, of transparent polyethylene bags filled with artificiallyinfested sphagnum peat moss with Pythium aphanidermatumand Fusarium oxysporum. Average daily maximum temperatures ofsolarized bags at five cm deep reached 51 and 54.2ºC in the springand summer experiments, an increase of 16.8 and 16.9ºC, respectively,over temperatures of non solarized shaded bags. In thesummer experiment, all tested pathogens were completely eliminatedwithin two days at both depths, surface at 0-7.5 cm and inner layer ofpeat moss, 7.5-15 cm. In the spring experiment, however, F. oxysporumsurvived solarization better than P. aphanidermatum. It tooksix and eight days to eliminate the former at the surface and innerlayer of the peat moss bags, respectively. The latter, on the otherhand, took two and six days to be eliminated, respectively. The numberof both fungi was significantly not affected in the shaded bagswith a fluctuation in the population. Solarization of peat moss in clearplastic bags is a very efficient, economical, safe and easy method toeradicate plant pathogenic fungi even at cooler seasons.