Effect of Bio-control Agents Using a Compost-based Organic Medium on Citrus Plant Growth and on Phytophthora Root Rot

摘要

A compost-based organic medium composed at the Mediterranean Agronomic Institute of Bari (MAIBBio-ECOS) was tested alone and in combination with two biocontrol products to assess their effect on citrus rootstocks and on Phytophthora root rot. Clonotri (a fungal mix based on Trichoderma harzianum and Clonostachys rosea) and Sublic (a bacterial mix based on Bacillus Hcheniformis and B. subtilis) were applied as a drench to potted citrus seedlings. P. raicorianae-inoculated and non-inoculated growing media were used as controls. Trials were carried out on 3 to 4 month-old Volkameriana lemon, Troyer citrange and sour orange seedlings transplanted into MAIB-BIO-ECOS growing medium inoculated with P. nicotianae. Responses to the bio-control products varied among the tested rootstocks. Clonotri was effective on Troyer citrange and sour orange seedlings, significantly enhancing plant growth and reducing root rot incidence; Sublic reduced rhizosphere population of P. nicotianae for all rootstocks except Troyer citrange, whereas it increased plant growth of only Volkameriana lemon.