Effect of Trichoderma asperellum strain T34 on Fusarium wilt and water usage in carnation grown on compost-based growth medium

Suppressive composts are viable alternative growth media for the biological control of plant diseases. To adapt the physical properties of these composts to growth conditions, formulation is sometimes required and consequently their suppressive capacity is reduced. Green house experiments show that plant growth medium based on grape marc compost (compost:peat 1:1, v/v) amended with the biological control agent Trichoderma asperellum strain T34, restores composts' suppressive capacity against Fusarium wilt of carnation compared with the non-amended medium. Standard chemicals (tocloflos-methyl 50% and captan 85%) used in the cultivation of carnation crops did not improve the suppressive capacity of the growth media or the T34 populations. However, they impaired the stomatal conductance of plants and increased the populations of the pathogen (interaction chemical and T34). Water use measurements of carnation plants, namely stomatal conductance, transpiration and daily water uptake, correlated negatively with Fusarium wilt disease. Plants in T34-amended growth media had higher water demand, regardless of the treatment, which implied their growth could be enhanced by increasing fertirrigation, compared to plants non-amended with T34. In conclusion, the amendment of formulated grape marc compost with T. asperellum T34 improves the suppressive capacity of this growth medium against Fusarium wilt in carnation. It is a better alternative for plant and disease control than the standard chemicals used. (c) 2010 Elsevier Inc. All rights reserved.