Prospection des principaux champignons (Phytophtora spp. et Phoma tracheiphila) et du virus de la psorose des agrumes dans la région du Cap Bon, Tunisie
The incidence and distribution of Phytophthora spp., Phoma tracheiphila and citrus psorosis virus (CPsV) was evaluated in the area of Cap Bon regarding a severe defoliation of citrus plants. Phytophthora spp. colonies obtained on selective media were identified as P. citrophthora and P. nicotianae by morphological characteristics and PCR. Significantly higher values of root infection (RI) and inoculum density (ID) were found in plants showing symptoms of decline and defoliation; RI was significantly lower under drip irrigation than under furrow irrigation. The highest incidence of P. tracheiphila was obtained in the oldest orchards (100%). Laboratory analysis revealed that only chromogenic isolates of Phoma tracheiphila were associated with the disease. CPsV infection rate by DTBIA using ovary (20,3%), was mainly affecting Clementine (38,1%).
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Systemic discolorations were observed on Chenopodium amaranticolor inoculated with a Tunisian CPsV infected source which showed serological similarities with Italian CPsV isolates.
