Survey of attraction value of the mirid predator, Nesidiocoris tenuis(Reuter) toward healthy and damaged tomato plants
عنوان دوره: دومین کنگره بین المللی حشره شناسی ایران
نویسندگان
چکیده
Plants produce herbivore induced plant volatiles (HIPVs) while been attacked by herbivory pests. In addition, HIPVs warn herbivore proximity to other plants, they also attract natural enemies to the plants. Their emissions depend on plant cultivar and level of infestation. Nesidiocoris tenuis (Reuter) is one of these predators, which has been extremely effective in controlling Tuta absoluta. (Meyrick) The preference of this predator to two cultivars of tomato plant (Cal JN3 cv.and Early Urbana Y cv.) was tested in two separate behavioral procedures. The first experiment was performed in a flight tunnel (120× 45×45 cm). Three different treatments were set up as: 1) healthy tomato plant versus plant infested by 20 T. absoluta larvae; 2) healthy tomato plant versus plant with 20 mechanically damaged leaves ; and 3) plant infested by 20 T. absoluta larvae versus plant with 20 mechanically damaged leaves. The predator did not show any preference between healthy tomato plant and plant with mechanically damaged leaves in Early Urbana Y (P=0.703), as well as between plant infested by T. absoluta and plant with mechanically damaged leaves in Cal JN3 (P=0.056). Conversely, the predator significantly preferred plant with mechanically damaged leaves more than healthy tomato plant in Cal JN3 (P=0.003), and plant infested by 20 T. absoluta compared with plant with mechanically damaged leaves in Early Urbana Y (P<0.0001). The next experiment was carried out with foursome-choice olfactometer. Each arm of the olfactometer was attached to a Plexiglas container. There was a blower fan in each container and an exhaust fan at the bottom of the olfactometer. Healthy tomato plant, plant infested by 20 T. absoluta larvae, plant with 20 mechanically damaged leaves and air as a neutral control were used as treatments. For each cultivar, 50 predators were used in five minutes (300 seconds). For Early Urbana Y cultivar, there was significant difference among responses of N. tenuis to sections of main chamber related to plant infested by T. absoluta larvae (108.62±15.69) compared with healthy plant (52.66±14.4) and air (51.58±12.8). For Cal JN3 cultivar, the predator significantly preferred sections of main chamber related to mechanically damaged plant (117.36±19.3) and infested plant by T. absoluta larvae (93.36±17.88) compared with healthy plant (40.40±12.28) and air (30.40±10.56). It can be concluded that the response of the predator to plant volatiles would be different according to plant cultivars,as well as we can use this volatiles to improve integrated pest management programs.
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