نوع مقاله : مقالات پژوهشی
نویسنده
دانشگاه رازی کرمانشاه
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسنده [English]
Introduction: Margarodidae, which are the largest adult females of the Coccoidea, are found both above and under ground parts of the host plants. All species typically found above ground have been removed from margarodids (Gaint scale) by Jakubski and includes only the cyst form of margarodids, which is divided to four sub-families, Neomargarodinae, Porphyrophorinae, Eumargarodinae and Margarodinae. Recently, Margarodidae sensu stricto, include 10 hypogeal genera. Genus Neomargarodes is one of several hypogeal genera, which consists of 26 recognized species. They are occuring worldwide, with most of the species in centeral Asia. Neomargarodes spp generally occur on roots of a wide variety of plant from annual grasses to perennial shrubs and perhaps even trees. The characters of major taxonomic importance of adult female of Neomargarodes genus are fossorial prothoracic legs, prothoracic claw with a prominent heel, 7-8 pairs abdominal spiracles, multilocular disc-pores and long hair-like setae throughout body, thoracic and abdominal spiracles with pores in atrium, perispiracular sensillia, absence of mouthparts, antennal apical segment with flagellate setae and fleshy setae, simple anal tube, genital opening surrounded by a radially folded membranous area. They are living underground on roots or crown of hosts and having a cyst-form second instar nymph. The common name “ground pearls” is derived form pearl–like cyst stage. The Neomargarods genus differs from all other related genera, mainly in having prothoracic claw with a prominent heel. Here, we present the results of a survey on a root species coccid collected from Medicago sativa L., a perennial herbaceous legume, with superior forage quality in Iran. Morphological studies on the collected speciments were conducted to determine its species name in order to decide on integrated management of pest and its control by using the results of this study. The objectives of this work are root coccid recognition and morphological description of the adult female.
Materials and Methods: During 2010, in Songhor, Kermanshah, the specimens were collected by cutting the infested roots of alfalfa, Medicago sativa, when the second instar were in the mature cyst stage and then the samples were kept in the black plastic carry bag in the normal lab condition, till adult emergence. The material preserved in 75% alcohol and than microscope slides were prepared. The morphological characters are described, illustrated and take photographs based on preparation, by using light microscopy. with mounted digital camera.
Results and Discussion: This species is identified as Neomargarodes sp. nr. festucae. belongs to ground pearls, family Margarodidae sensu stricto. Based on observation, the 1st and 2nd namphal instar stages in large numbers feed on the root of lucerne, Medicago sativa. Morphological study shows the adult female with 6 segmented antennae; thoracic spiracles with 6-8 multilocular disc-pores, narrow biforked spiracular apodeme; 4 spiracular sensilla, 5-8 abdominal spiracles, powerful and fossorial prothoracic legs, short femur, length of tibia+ tarsus femur and claw fused with the tarsus, basal bulbous protrusion of the claw is very extended, genital opening surronded by a radially folded membranous area. Neomargarodes sp. nr. festucae is new record for Iran. Addition record, cultivated alfalfa, Medicago sativa (Leguminose family) have not been reported as host for Neomargarodes spp from the other parts of the world,. It is not possible to recognize this species using a single character for various reasons. Most characters are relatively variable, more than one of the characters is almost always obscured by other structures and presence of characters which are shared by many other species.
Conclusion: The basic structure of the adult female of Neomargarodes sp. nr. festucae appears very similar to that of Neomargarodes festucae apart from host plant Medicago sativa (Leguminose family) and a number of unstable morphological character, such as prominent basal heel with a dentical and thoracic spiracular apodeme with a biforked shap. So, based on the unstable futures character and polyphagus Neomargarodes species with broad spectrum of host plants, can not say that this species is a new species. Because two species, N. borchsenii (Hadzibejli) and N. setosus (Borchsenius) on roots of Festuca and Compositae in Georgia, have been become synonym with Neomargarodes festucae (Archangelskaya). Although, the rest of recorded species of Neomargarodes from the Middle East have not recorded off Medicago spp., but, other species N. niger (Green) from China, India and Pakistan have been recorded off Leguminose, such as Alhagi camellorum and Arachis hypogaea which are close related to Medicago spp.. Moreover, N. niger (Green) recorded off Gramineae: such as Cynodon dactilon, and undetermined perennial grass.
As with Porphyrophora species for example Porphyrophora medicagenis from USSR and Porphyrophora sp from Songhor, Kermanshah were found on roots of cultivated alfalfa, as same as Neomargarodes sp. nr. festucae. Addationaly in Songhor, Kermanshah,Western parts of Iran. P. tritici infests wheat and barley and Vahedi (1999) found some effective farming practices on its population and suggest an on time ploughing to reduce P. tritici population. Contrary to, irrigation experiment has no negative effect on its population. It is here recommended that the manipulation of ploughing times can be effective for population reduction of Neomargarodes sp. nr. festucae in the infested field. In the end, considered that all root coccids, for example Porphyrophora spp and Neomargarodes spp no need chemical control at all.
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