| heal.abstract |
Nesidiocoris tenuis (Reuter) (Heteroptera Miridae) is an important natural enemy of whiteflies in Mediterranean field and protected tomato crops. However, this species has been related to the damage induction on tomato plants. Feeding on tomato plants may cause the development of necrotic rings on the stems and flower abortion. This damage has been reported as important in certain cases whereas in other studies there was very low damage evidence. In our study, the damage potential of the predator was evaluated on caged tomato plants. On the plants no prey was present. Various densities of different stages of the predator were released on each plant. These densities were 16 and 32 young nymphs (of the 1st, 2nd or 3rd instar), 16 and 24 large nymphs (4th or 5th instars) and finally 16 and 32 adults. In all cases controls were used. The number of necrotic rings on the stem, and each leaf was recorded after 9, 16 and 23 days of the predators' release in the cages. Damage on the flower clusters was recorded one month after the predator's release. According to the results, the predator inflicted a very small number of necrotic rings on the stems and the flowers and thus this damage was not considered as important. Flower abortion was not observed and the number of rings on the flower petioles was kept at very low levels. The number of flowers developed was similar to that of the control plants. Therefore, our experiments showed that this predator has a low potential to cause damage on tomato stems and flowers even when it occurs at high densities. However, further studies should explore its damage potential after a longer interaction with the plants and under a wider range of temperatures than those evaluated in the present work. In addition, studies on damage records on fruits could highly contribute to a more thorough investigation on the damage potential of this mirid. |
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