Interaction between arbuscular mycorrhizal fungi and Trichoderma harzianum under conventional and low input fertilization field condition in melon crops: Growth response and Fusarium wilt biocontrol

The objective of this work was to evaluate the interactions between four arbuscular mycorrhizal fungi (AMF) (Glomus intraradices, Glomus mosseae, Glomus claroideum, and Glomus constrictum) and the beneficial fungus Trichoderma harzianum, inoculated in a greenhouse nursery, with regard to their effects on melon crop growth under conventional and integrated-system field conditions, and the biocontrol effect against Fusarium wilt. A synergistic effect on AM root colonization due to the interaction between T. harzianum and G. constrictum or G.intraradices, was observed under a reduced fertilizer dosage, while no significant effect was observed for G. claroideum or G. mosseae. With the reduced fertilizer input, AMF-inoculated plants and T. harzianum-inoculated plants had improved shoot weight and nutritional status, but the combined inoculation of AMF and T. harzianum did not result in an additive effect. Under the conventional fertilizer dosage, plant growth was not influenced by AM formation; however, it was increased significantly in T. harzianum-inoculated plants. The AMF-inoculated plants were effective in controlling Fusarium wilt. G. mosseae-inoculated plants showing the greatest capacity for reduction of disease incidence. The T. harzianum-inoculated plants were more effective than AMF-inoculated plants with regard to suppressing disease incidence. Co-inoculation of plants with the AMF and T. harzianum produced a more effective control of Fusarium wilt than each AM F inoculated alone, but with an effectiveness similar to that of T. harzianum-inoculated plants. (c) 2010 Elsevier B.V. All rights reserved.