SOIL SOLARIZATION FOR THE CONTROL OF TOMATO WILT PATHOGEN (FUSARIUM-OXYSPORUM SCHL)

Soil solarization of infested soil by mulching with different polyethy lene mulches resulted in increased temperatures in the soil ecosystem lethal to tomato wilt pathogen (Fusarium oxysporum Schl.). The highest mean temperature both under dry (52.2-degrees-C) and wet (51.1-degree s-C) conditions was recorded in soil beneath the transparent (25 mum) polyethylene sheets, thus increasing the mean soil temperature by 12.6 -degrees-C and 14.3-degrees-C, respectively, at 6 cm depth. Soil tempe rature decreased with increase in soil depth. Soil solarization effect ively reduced pathogen population in soil. Mulching (transparent 25 mu m) for 15 and 60 days eliminated the pathogen from 6 and 24 cm soil de pth respectively, and decreased wilt incidence to zero level. Black po lyethylene mulch could eradicate the pathogen up to 6 cm only after 60 days of solarization. Disease could be detected in plots under black polyethylene tarps. However, pathogen could be detected at 24 cm soil depth under transparent mulch (75 mum) even after 60 days under unirri gated conditions. Wet heat was found more lethal than the dry one. Ino culum build up was more under wet non-tarped microplots. Disease incid ence in the untreated plots was significantly and negatively correlate d with yield. Mulching has positive influence on plant growth.