author(s)
Ettaib Refki, Belkadhi Mohamed Sadok and Ben Belgacem Ali

abstract
Nesidiocoris tenuis is a predator bug spontaneously present in horticultural crops. Recently, it is used for several pests’ biological control. In this work we evaluated its predator effect to control Tuta absoluta in geothermal waters heated tomato greenhouses, at various stages of their life cycles. Our results showed that N. tenuis preferentially feeds on T. absoluta eggs, and the predation effect significantly diminished within advanced developmental stages of the pest. In addition, L1 and L2 larvae of T. absoluta were the most attacked by the third nympha of N. tenuis (1.5 ± 0.57 and 1.25 ± 0.50. respectively) in comparison to other stages e.g. N1 0.50 ± 057 and 0.25 ± 0.50, respectively at p≤0.05). These findings spotted the importance of indigenous N. tenuis as biological agent to manage the ravaging insect T. absoluta in geothermal-greenhouses. The predator should be introduced, in a manner where N. tenuis third nymphs meet the L1 and L2 developmental stages of T. absoluta, in order to maximize the effect.