The combined effect of Trichoderma harzianum and Nesidiocoris tenuis inoculation on water stress in tomato

Abstract: In tomato crops in southern Europe and North Africa, the zoophytophagous predator Nesidiocoris tenuis is widely used as a biological control agent. However, this predator also feeds on the tomato plant, which under certain circumstances, results in plant damage (flower abortion, necrotic rings and apical desiccation). Recently the use of certain endophytic fungi in tomatoes has been shown to reduce the damage caused by N. tenuis. In this work, the effect of using the soil-borne beneficial fungus Trichoderma harzianum and N. tenuis (individually and combined) in tomato plants was studied under three water stress levels (regular, light and moderate stress). Our results showed that the greater the water stress, the more damage caused by N. tenuis. The inoculation of T. harzianum improved the resistance of the tomato against water stress. Interestingly, in the treatments where N. tenuis was established in plants inoculated with T. harzianum; the incidence of N. tenuis damage was lower than in plants without T. harzianum. These results show the benefit of combining both biological control agents in a global context of climate change, where water stress management will be essential.