First Report of the Root-Knot Nematode Meloidogyne marylandi on Turfgrasses in Israel.

Abstract

In a turfgrass nursery in Arava, Israel, a population of root-knot nematodes was isolated from poorly growing Zoysiagrass (Zoysia japonica Steud.) with symptoms of foliar chlorosis and roots with very small, smooth galls and protruding egg masses. The isolated population (genus Meloidogyne) included females and second-stage juveniles, whereas no males were observed. Measurements and morphological observations of 20 second-stage juveniles (body length = 423 ± 13 μm, dorsal gland orifice from stylet base = 2.6 ± 0.4 μm, tail length = 63 ± 3 μm, hyaline tail length = 12.4 ± 0.9 μm and hemizonid posterior to excretory pore) and 10 adult females (stylet length = 12.5 ± 0.7 μm, dorsal gland orifice from stylet base = 3.3 ± 0.5 μm, excretory pore to head end = 11.9 ± 1.3 μm and perineal patterns rounded to ovoid with coarse striae) conformed to the description of Meloidogyne marylandi Jepson and Golden (3). Additionally, the identification was confirmed when females and second-stage juveniles were compared with available paratype slides. The isozymes malate dehydrogenase (EC 1.1.1.37) and esterase (EC 3.1.1.1) of young, adult females were also different from those of other described root-knot nematode species, including M. graminis, a taxon closely related to M. marylandi (4). M. marylandi was discovered and described from Bermudagrass (Cynodon dactylon (L.) Pers) in Maryland in 1987. Outside the United States, it has only been isolated from Zoysia matrella in Japan (1,2,3). In host range tests with different turfgrasses, stolons with roots were inoculated after 1 week with 500 second-stage juveniles per plant and 6 weeks later, the produced egg-masses where counted. These tests showed that this root-knot nematode isolate reproduced on Z. japonica and Pennisetum clandestinum, while no egg masses were observed on the roots of Dactyloctenium australe, Paspalum vaginatum, and Stenotaphrum secundatum. Additionally, some cereals grown from seeds were tested. Wheat (Triticum aestivum), barley (Hordeum vulgare), and bristle oat (Avena strigosa) were infested with this nematode, while oat (A. sativa) was not. Although the origin of this root-knot nematode in Israel is unknown, it could have been distributed throughout the country with commercial turfgrass. To our knowledge, this is the first report of M. marylandi in Israel and outside the United States and Japan.