The effect of symbiotic fungal of tall fescue grass in control of Tetraneura ulmi (Hem.: Aphididae) in urban green space
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عنوان دوره: سومین کنگره بین المللی حشره شناسی ایران
نویسندگان
1Branch for Northwest and West Region, Agricultural Biotechnology Research Institute of Iran (ABRII), AREEO, Tabriz, Iran
2Branch for Northwest and West Region, Agricultural Biotechnology Research Institute of Iran (ABRII), AREEO, Tabriz, Iran, r.mohammadi@abrii.ac.ir,
3Branch for Northwest and West Region, Agricultural Biotechnology Research Institute of Iran (ABRII), AREEO, Tabriz, Iran,
چکیده
Cool-season grasses have symbiotic relationship with endophytic fungal symbionts of the genus Neotyphodium. The endophytic fungal are transmitted maternally (vertically) through seeds. These fungi do not cause any disease in the host grass, but they produce different types of secondary metabolites in their host plants and confer protective effects to the biotic and abiotic stresses. The protection against grass pests is mainly due to the production of peramine and lolines alkaloids. A study was carried out to investigate the biological control of Elm-grass root aphid (Tetraneura ulmi) in native Iranian tall fescue (used as lawn in urban green spaces) which is naturally infected by Neotyphodium coenophialum endophytic fungi. In order to evaluate the effect of endophyte on pest control, two native infected tall fescue genotypes were selected and each genotype was splitted into two parts and one part was treated by Propiconasol fungicide to make endophyte free clones. New tillers from endophyte-infected (E+) and endophyte-free (E-) clones were transferred to different pots in 4 replications in a complete block design. Then a Free-choice assay (Antixenosis) was carried out to assess the E+/E- plants preferences of aphides. The assay was set up in a cylindrical plastic cage, and the potted plants with similar vegetative growth were randomly selected. For each replicate, 20 infested grass roots were placed in the center of the ring of test pots. Preference of aphids for feeding was measured based on the mean number of aphids on infested roots. Endophyte-free (E-) plants had infestation up to 15 aphids on infested pots but on endophyte-infected (E+) plants, the number of aphids hardly exceeded one. In a No-choice assay (Antibiosis), 30 adult aphids were released on the plants and after 5 months, the total number of aphids on roots was counted. Infected plants (E+) had significantly lower number of aphides compared to endophyte-free plants (E-). The results showed that symbiotic fungi have a potential to increase the resistance of tall fescue grass against the pests and control them in urban green space. Complementary research is required to find out the side effects of the endophyte fungi on upper levels in food chain (predators and parasites) before drawing any conclusion.
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