Dolichodorus | |
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Genus: | Dolichodorus Cobb, (1914) |
Species | |
about 15 |
Dolichodorus is a genus of nematodes known commonly as awl nematodes. [1] [2] They are distributed worldwide. [1] They are ectoparasites of plant roots, and some are pests of agricultural crops. [1]
These are among the largest plant-parasitic nematodes, reaching 1.5 to 3 millimetres (0.059 to 0.118 in) in length. [1] They are slender and cylindrical in shape with annular rings along their bodies. They have long, strong stylets. There are male and female individuals in each species, and they reproduce sexually. The male has winglike folds surrounding its cloaca. Its sex organs include a pair of flanged spicules and a protruding gubernaculum to guide them during mating. The female has a rounded or hemispherical tail with a spike-shaped tip. [2]
Awl nematodes generally occur in moist and wet soils. In agricultural habitat they are common around irrigation ditches and ponds. [1]
Adults and juveniles feed on plant roots. Damage is apparent when the root tips turn brownish yellow and develop lesions. The root tips die, the roots become coarse and curved, and the root system looks "stubby". [1] A plant is stunted as its roots are destroyed. [1]
The genus can be found on many host plant taxa. D. heterocephalus has been noted on a variety of crop plants, including sugarcane, beans, tomato, blueberry, and corn. D. kishansinghi is known from mango. D. mediterraneus is known from cork oak. D. silvestris is found on white pine. Several species occur on the coconut palm. They are found in the roots of grasses such as bromegrasses, bluegrasses, Manila grass, St. Augustine grass, bermudagrass, and centipedegrass. [3]
There are approximately 15 species. [2]
Species include: [4]
Radopholus similis is a species of nematode known commonly as the burrowing nematode. It is a parasite of plants, and it is a pest of many agricultural crops. It is an especially important pest of bananas and citrus, and it can be found on coconut, avocado, coffee, sugarcane, other grasses, and ornamentals. It is a migratory endoparasite of roots, causing lesions that form cankers. Infected plants experience malnutrition.
Meloidogyne incognita, also known as the "southern root-nematode" or "cotton root-knot nematode" is a plant-parasitic roundworm in the family Heteroderidae. This nematode is one of the four commonest species worldwide and has numerous hosts. It typically incites large, usually irregular galls on roots as a result of parasitism.
Belonolaimus longicaudatus is a common parasite of grasses and other plant crops and products. It is the most destructive nematode pest of turf grass, and it also attacks a wide range of fruit, vegetable, and fiber crops such as citrus, cotton, ornamentals, and forage. The sting nematode is a migratory ectoparasite of roots. It is well established in many golf courses and presents a problem in turf management. The sting nematode is only present in very sandy soils. It cannot reproduce in heavier or clay soils.
Rotylenchulus reniformis, the reniform nematode, is a species of parasitic nematode of plants with a worldwide distribution in the tropical and subtropical regions.
Meloidogyne arenaria is a species of plant pathogenic nematodes. This nematode is also known as the peanut root knot nematode. The word "Meloidogyne" is derived from two Greek words that mean "apple-shaped" and "female". The peanut root knot nematode, M. arenaria is one of the "major" Meloidogyne species because of its worldwide economic importance. M. arenaria is a predominant nematode species in the United States attacking peanut in Alabama, Florida, Georgia, and Texas. The most damaging nematode species for peanut in the USA is M. arenaria race 1 and losses can exceed 50% in severely infested fields. Among the several Meloidogyne species that have been characterized, M. arenaria is the most variable both morphologically and cytologically. In 1949, two races of this nematode had been identified, race 1 which reproduces on peanut and race 2 which cannot do so. However, in a recent study, three races were described. López-Pérez et al (2011) had also studied populations of M. arenaria race 2, which reproduces on tomato plants carrying the Mi gene and race 3, which reproduces on both resistant pepper and tomato.
Paratrichodorus minor is a species of nematode in the family Trichodoridae, the stubby-root nematodes. It occurs in tropical and subtropical regions of the world. It damages plants by feeding on the roots and it is a vector of plant viruses. It is a pest of some agricultural crops.
Pratylenchus brachyurus is a plant parasitic nematode.
Pratylenchus penetrans is a species of nematode in the genus Pratylenchus, the lesion nematodes. It occurs in temperate regions worldwide, regions between the subtropics and the polar circles. It is an animal that inhabits the roots of a wide variety of plants and results in necrotic lesions on the roots. Symptoms of P. penetrans make it hard to distinguish from other plant pathogens; only an assay of soil can conclusively diagnose a nematode problem in the field. P. penetrans is physically very similar to other nematode species, but is characterized by its highly distinctive mouthpiece. P. penetrans uses its highly modified mouth organs to rupture the outer surface of subterranean plant root structures. It will then enter into the root interior and feed on the plant tissue inside. P. penetrans is considered to be a crop parasite and farmers will often treat their soil with various pesticides in an attempt to eliminate the damage caused by an infestation. In doing this, farmers will also eliminate many of the beneficial soil fauna, which will lead to an overall degradation of soil quality in the future. Alternative, more environmentally sustainable methods to control P. penetrans populations may be possible in certain regions.
Globodera pallida is a species of nematode in the family Heteroderidae. It is well known as a plant pathogen, especially of potatoes. It is "one of the most economically important plant parasitic nematodes," causing major crop losses, and is a model organism used to study the biology of cyst nematodes. Its common names include potato cyst nematode, white potato cyst nematode, pale potato cyst nematode, potato root eelworm, golden nematode, and pale cyst nematode.
Heterodera avenae, the cereal cyst nematode or European cyst nematode, is a plant pathogen and an obligate parasite of cereal crops including barley, oats, wheat and rye. Cereal crops infected with this nematode are more susceptible to infection by fungal diseases such as rhizoctonia root rot.
Hirschmanniella oryzae, i.e. rice root nematode (RRN), is among the major pests of rice and is the most common plant-parasitic nematode found on irrigated rice. Recent modifications in cultivation practices have led to a substantial increase in rice production, which has been accompanied by heightened levels of RRN. The proportional increases in RRN with rice production can be explained by the nematode's impeccable adaptation towards constantly flooded conditions in which irrigated rice is often being grown.
Paratylenchus hamatus, the fig pin nematode, is a species of migratory plant endoparasites, that causes lesions on plant roots resulting in symptoms of chlorosis, wilting and ultimately yield losses. They move and feed on different parts of host tissue throughout their life cycle in order to find enough susceptible host tissue to survive and reproduce. A wide range of host plant species are susceptible to the fig pin nematode, including many valuable fruit and vegetable crops such as figs, carrots and celery. They are also commonly found associated with woody perennials in California. P. hamatus inhabits soils in both Europe and North America, and was originally isolated from fig in central California in 1950.
Xiphinema americanum is a species of plant pathogenic nematodes. It is one of many species that belongs to the genus Xiphinema. It was first described by N. A. Cobb in 1913, who found it on both sides of the United States on the roots of grass, corn, and citrus trees. Not only is Xiphinema americanum known to vector plant viruses, but also X. americanum has been referred to as "the most destructive plant parasitic nematode in America", and one of the four major nematode pests in the Southeastern United States.
Xiphinema diversicaudatum is an amphimitic ectoparasitic nematode species. This species has a characteristically long stylet capable of penetrating into a host’s vascular tissue. They have a wide host range with some of the extensively studied ones being strawberry, hops and raspberry, due to their economic importance. The direct root damage caused through penetration near the root tip and formation of galls is a secondary concern when compared with the damage caused by vectoring the arabis mosaic virus. The virus attaches to the interior cuticle lining and can be transferred from infected to uninfected root tissue as the nematode feeds and sheds. Management of this particular nematode relies on nematicides such as 1,3-Dichloropropene (Telone) at 40 gpa.or methyl bromide at 1000 lb/ac to control to 28 in deep.
Xiphinema index is a species of plant-parasitic nematodes.
Mesocriconema xenoplax is a species of plant parasitic nematodes. Nematodes of this particular species are collectively called ring nematodes.
Anguina agrostis is a plant pathogenic nematode.
Heterodera sacchari mitotic parthenogenic sedentary endoparasitic nematode. This plant-parasitic nematode infects the roots of sugarcane, and the female nematode eventually becomes a thick-walled cyst filled with eggs. Aboveground symptoms are species specific and are similar to those caused by other Heterodera species. Symptoms include: stunted and chlorotic plants, and reduced root growth. Seedlings may be killed in heavily infested soils.
Hoplolaimus is a genus of nematodes known commonly as lance nematodes. They are parasites of plants, and three species are pests of agricultural crops.
Helicotylenchus is a genus of nematodes in the family Hoplolaimidae. They are known generally as spiral nematodes. They are found worldwide because they can live and survive in a wide range of habitats. They are among the most common parasitic nematodes of plants; found in corn, bananas, grass, soybeans.