Solarization has been efficient in controlling soil borne pathogens. Phytophthora parasitica, the causal agent of root rot in citrus (Citrus spp.) nurseries, is usually treated by using methyl bromide for soil disinfestations. This product is highly toxic to man as well as to the soil microbial community. Solarization was efficient in both winter and summer P. parasitica pre-colonized substratum. The winter experiment was arranged in a randomized block design with eight treatments (solar collector 24 h and 48 h, plastic bag 24 h and 48 h, solar collector 48 + Trichoderma spp., Trichoderma spp., inoculated and non-inoculated control at shadow), with four repetitions using 15 plants/parcel. Inoculated treatments were solarized and used to fill the containers where seedlings were transplanted. Evaluation was made by means of bait test for recovering pathogen and by citrus seedling development three months later. For summer solarization, the effect in plastic bags was evaluated at one, two, seven and 14 days. This evaluation was made by bait test. Results showed that the solarization of substratum for seedling production eliminates P. parasitica in solar collectors (10-cm-diameter containers) for 24 h in winter as well as in summer (allowing a better seedling growth), and in plastic bags (20 x 25 x 4 cm³) for 48 h in summer.
