Interactions between Onychiurus armatus and Trichoderma harzianum in take-all disease suppression in a simple experimental system

In a simple experimental system with wheat plants, interactions between the collembolan Onychiurus armatus and Trichoderma harzianum, a soil-borne fungus parasite of several plant pathogenic fungi, were studied in the presence of Gaeumannomyces graminis var. tritici, one of the most important foot and root fungal pathogens of cereals world-wide. Trichoderma harzianum was used according to two different modalities: fungal inoculum applied to seed or mixed with substrate. The isolate of T harzianum proved to be ineffective against the pathogenic fungus, independent of the application modality, as shown in the experiments where this fungus was used alone, whereas Collembola used alone significantly reduced disease severity. However, the mode by which harzianum was applied significantly influenced the disease control ability of Collembola. In fact, only when T harzianum was coated to seed were springtails able to reduce the disease caused by G. graminis var. tritici. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved