Effect of soil temperature on infective capacity of Fusarium oxysporum f. sp. dianthi in presence of poplar bark compost

Abstract

Summary The effect of soil temperature on infective ability of Fusarium oxysporum f. sp. dianthi against carnation plants cultivated in a soil amended with poplar bark compost has been investigated. The compost has been divided in two parts: one sterilized and the other one not sterilized. Subsequently, those two kinds of compost have been added to the same soil on three greenhouse benches. The experimentation has been carried out by maintaining the soil of each bench at a different temperature, namely 16, 23, 30°C. Temperature and humidity of ambient-air in the greenhouse have been maintained everywhere at the same values. Variations of most important soil microbial groups have been analyzed and visual readings of plant mortality have been taken on 15 days intervals. It has been shown that soil temperature has no appreciable effect on Fusarium pathogenicity. On the contrary, a less incidence of the disease has been observed in amended soils (both with sterilized and not sterilized compost), with respect to control soils. This occurrence has been more evident in soil amended with sterile compost, at increasing temperatures. Likely, nutrients added by compost has caused a response of zymogenic soil-microflora, which is responsible of the protection against disease. Consequently, the soil temperature influenced the incidence of the disease, simple by acting as a selective factor controlling the growing of microbial soil population.