| Pratylenchus zeae | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Nematoda |
| Class: | Secernentea |
| Order: | Tylenchida |
| Family: | Pratylenchidae |
| Genus: | Pratylenchus |
| Species: | P. zeae |
| Binomial name | |
| Pratylenchus zeae Graham, 1951 | |
Pratylenchus zeae is a plant-pathogenic nematode found on potatoes, maize, cereal, tobacco, coffee, blackberry, and found most often on sugarcane.
Female is slender, 0.4–0.55 mm long. Body almost straight when heated. Low and flat lip region. Labial region not offset from the body. Short and strong stylet with well- developed basal knobs. Conical, rounded tail. Esophagus overlaps ventrally. Monovarial, oviduct indistinct, prodelphic and short uterus. Phasmids slightly posterior to mid-tail. [1]
Male is extremely rare, not essential for reproduction. Similar to female except for sexual dimorphism. Spicules slender. [1]
Nematode becomes a concern to farmers when the number feeding on the roots exceeds a certain threshold, above which the plant is unable to grow normally. This threshold varies according to the species of nematode. For Pratylenchus zeae, because the level exceeds in many fields in Australia so that P. zeae is considered the primary nematode. Where the number of nematode individual exceeds 100 per 200 gram pre planting soil or above 200 per 250 gram soil or 1 gram dry roots at mid- season, there are a significant reduction of sugarcane yield. [2] The economic damage from lesion nematodes is often underestimated because above-ground symptoms are not always obvious. No recent data are available regarding damage caused by these pathogens to this crop, but it is known that controlling them raises yields by between 8% and 40%, depending on the species of nematode and hybrid planted. [1]
Nematode assays need to be done before stepping on any managements later. Threshold for plant and first ratoons (per gram of roots) is 300 while threshold for old ratoons (per gram of roots) is over 900. [3] Crop rotation with legume plants on sugarcane fields can reduce the number of plant parasitic nematodes. However, this management has a temporary effect because a high concentration of these nematodes will be resurged within a year of growing fields. [4]
Rotations on wetland rice in Florida is one of the options. Many of the nematodes that feed on sugarcane are able to feed on rice under dry conditions. However, because rice is normally grown in standing water, most of the nematodes are killed by the flooded conditions. [5] Using oil cake from neem (Azadirachta indica), karanj (Pongamia pinnata), Indian mustard (Brassica juncea), polanga (Calophyllum inophyllum), groundnuts (Arachis hypogaea), mahua (Madhuca longifolia) and cotton (Gossypium sp.) could suppress population of P. zeae. [6] Sugarcane grown in soil amended 6 months previously with sawdust, sugarcane trash, grass hay or lucerne hay had 78%, 61%, 96% and 92%, respectively, fewer lesion nematodes in roots than sugarcane growing in non-amended soil. [7] Amendments with high C/N ratios are most effective. [4]
P. zeae populations can be controlled through by weed-free fallow. [8] A few nematicides are labeled for use on sugarcane. Mocap (ethoprop) and telone products are common nematicides used in Florida to control wireworms and also labeled to control plant parasitic nematodes. [5]
Root-knot nematodes are plant-parasitic nematodes from the genus Meloidogyne. They exist in soil in areas with hot climates or short winters. About 2000 plants worldwide are susceptible to infection by root-knot nematodes and they cause approximately 5% of global crop loss. Root-knot nematode larvae infect plant roots, causing the development of root-knot galls that drain the plant's photosynthate and nutrients. Infection of young plants may be lethal, while infection of mature plants causes decreased yield.
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 most common 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.
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.
Helicotylenchus multicinctus is a plant pathogenic nematode that affects primarily bananas and plantains. Nematodes of the genus Helicotylenchus are spiral nematodes and feed on a large variety of plant species.
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, the American dagger nematode, 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 amphimictic 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.
Tylenchulus semipenetrans, also known as the citrus nematode or citrus root nematode, is a species of plant pathogenic nematodes and the causal agent of slow decline of citrus. T. semipenetrans is found in most citrus production areas and diverse soil textures worldwide. Their feeding strategy is semi-endoparasitic and has a very narrow host range among commonly grown crops. These nematodes are considered as major plant-parasitic nematode because they can cause 10-30% losses reported on citrus trees. They also parasitize other hosts such as olive, grape, persimmon and lilac. The citrus nematode was first discovered in California in 1913 by J. R. Hodges, a horticultural inspector for Los Angeles County, and was later described and named by Nathan Cobb that year. T. semipenetrans is the only species of Tylenchulidae that are economically important to agriculture.
Mesocriconema xenoplax is a species of plant parasitic nematodes. Nematodes of this particular species are collectively called ring nematodes.
Heterodera sacchari, the sugarcane cyst nematode, 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.
Pratylenchus is a genus of nematodes known commonly as lesion nematodes. They are parasitic on plants and are responsible for root lesion disease on many taxa of host plants in temperate regions around the world. Lesion nematodes are migratory endoparasites that feed and reproduce in the root and move around, unlike the cyst or root-knot nematodes, which may stay in one place. They usually only feed on the cortex of the root. Species are distinguished primarily by the morphology of the stylets.
Strawberry foliar nematode, or strawberry crimp nematode, is a disease caused by Aphelenchoides fragariae, a plant pathogenic nematode. It is common in strawberries and ornamental plants and can greatly affect plant yield and appearance, resulting in a loss of millions of dollars of revenue. Symptoms used to diagnose the disease are angular, water soaked lesions and necrotic blotches. Aphelenchoides fragariae is the nematode pathogen that causes the disease. Its biological cycle includes four life stages, three of which are juvenile. The nematode can undergo multiple life cycles in one growing season when favorable conditions are present. The crowns, runners, foliage, and new buds of the plant via stylet penetration or through the stomata can be infected. The best management practices for this disease are sanitation, prevention of induction of the pathogen to the environment, and planting clean seed or starter plants.
Pratylenchus alleni is a migratory endoparasitic nematode, living inside of plant roots and feeding on parenchyma cells in the root cortex. P. alleni is an obligate biotroph, meaning it must have a living host in order to survive. Due to their incredibly broad host range, Pratylenchus species fall third in total economic impact, finishing just behind cyst nematodes and root knot nematodes (Meloidogyne). In Canada, it was isolated for the first time in 2011 in a soybean field.
Heterodera zeae, the corn cyst nematode (CCN), is a plant parasitic nematode that feeds on Zea mays (maize/corn). The CCN has a limited economic impact worldwide due to its high soil temperature requirements.
Scutellonema bradys, also known as yam nematode, is a migratory endoparasitic nematode causing major damage to yam crop in many African tropical regions, as well in parts of South and Central America and Asia. They can cause reduction of 20-30% in tuber weight at harvest.
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