Rev 01/08/2024
Tylenchina Tylenchoidea Pratylenchidae Pratylenchinae
Pratylenchus brachyurus (Godfrey, 1929) Filipjev & Schuurmans-Stekhoven, 1941
Lip region is generally low and flat. Head frame sclerotized.
Tail conical and rounded to flattened at tip.
Nematode has short ventral overlap of esophagus.
Monovarial, uterus prodelphic, short post-uterine sac.
Females are slender.
Males are extremely rare.
Molecular diagnostics are emerging.
Ref: Corbett, 1976; Subbotin et al., 2008.
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Pratylenchus brachyurus is widely distributed throughout the tropical and subtropical regions of the world. Type host was pineapple in Hawaii where it was described by Godfrey in 1929..
In the U.S. tit is reported from Alabama, Arkansas, California, Florida, Georgia, Hawaii, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia (CABI, 2023).
In surveys of the state of Mato Grosso in Brazil, 94% of cotton fields and 85% of soybean fields were infested with P. brachyurus (Da Silva et al., 2004; Miranda et al., 2010).
C-rated pest in California Nematode Pest Rating System.
Migratory endoparasite of roots.
Within plant roots, feeding is confined to the root cortex.
The nematode is readily cultured on carrot disks on 1% agar for detailed study of life cycle and other biological aspects (Moody et al., 1973).
Very wiide host range, including important economic crops:
Ecophysiological Parameters:
There are no males (extremely rare); females reproduce by mitotic parthenogenesis; the somatic chromosome number is 30-32 (Roman and Triantaphyllou, 1969). .In mitotic parthenogenesis there is no fertilization and there is mitotic division of oogonia so that the somatic number of chromosomes is preserved throughout.
Pratylenchus brachyurus enters plant roots and feeds, reproduces, and moves freely within the tissue, spending its entire life cycle inside of roots or in the soil around roots.
Like other Pratylenchus species, there are six life stages: egg, four juvenile stages, and adult. First-stage juveniles develop within the egg, followed by a first molt to the second-stage juvenile that hatches from the egg. Each stage develops into the next via a molt of its cuticle. The juvenile and adult stages are vermiform.
All post-hatch stages are motile and can infect plants.
Generally, root lesion nematodes have a life cycle of 45- 65 days, but the duration is affected by temperature and moisture.
Pratylenchus brachyurus survives the winter in infected roots or soil as eggs, juveniles, or adults. During spring, when plant growth is active, eggs hatch to commence the life cycle within roots or in rhizosphere soil (Agrios, 2005; Chitambar et al., 2018; Scheck, 2023).
Pratylenchus brachyurus causes damage to plants through its migratory endoparasitic feeding habits. It causes brown to black lesions to form on the roots. The damage to the root systems can lead to stunted growth, reduced plant vigor, chlorotic symptoms, defoliation, and a gradual decline in yield. The nematode burrows from cell to cell through the cortex. Necrotic patches within the root cortex occur after 24 hours in tobacco, 4 days in pineapple.
Related symptoms include poor vigor, reduced tillering, reduced grain yield and grain quality, and increased susceptibility to winter injury. The above-ground parts of the plants may exhibit symptoms of nutrient deficiency (Andressa et al., 2012; Chitambar et al., 2018; Lordello, 1986).
The appearance of the lesions varies according to the level of infestation, the age of the lesion, and the host species. When the lesion breaks open, the cortex sloughs off like a sleeve, leaving only the vascular cylinder. Secondary pathogens often enter these lesions causing rot (CABI, 2023). May result in vessel blocking in corn and root growth may cease in infected pineapple roots.
In peanuts, causes crop loss by weakening pegs so that pods drop off; lesions appear on pegs, pods, and shells. infection by P. brachyurus slows growth on young citrus in Florida, but effect diminishes with tree age (O'Bannon).
Affected plants often appear in patches and are not uniformly distributed. Patches of stunted plants are reported in soybean fields in Brazil Stunted and chlorotic plants give the field a �ragged� appearance. The damage is often most severe in the center of these areas; symptoms diminish toward the edges and plants appear increasingly normal (Scheck, 2023)..
The interaction of lesion nematodes and pathogenic soil fungi such as Verticillium, Rhizoctonia, and Fusarium can result in more severe disease complexes. Infected plants have roots with black lesions and fewer feeder roots than non-infected plants thereby resulting in stunted root growth. Top growth may exhibit general symptoms of an impaired root system including lack of vigor, dieback, and chlorotic and small leaves (Davis and MacGuidwin, 2000; Back et al., 2002).
Sanitation: Management of Spread and Introduction:
Lesion nematodes are spread through the movement of contaminated soil and infected plant debris. It is frequently detected in shipments of ornamental nursery stock.
The nematodes can be introduced into non-infested sites with poorly sanitized farm equipment, contaminated planting stock, such as tubers or seedlings, nursery stock, such as bare root trees, and irrigation water. The spread of lesion nematodes within fields is often accelerated by cultural practices, such as moving soil through cultivation (Davis and MacGuidwin, 2000).
Crop Rotation:
The wide diistribution and host range of this nematode are problematic. The cotton fields of Mato Grosso state in Brazil with 94% infestation of P. brachyurus are rotated to soybean and corn, both hosts of the nematode (Da Siva et al., 2004).
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Biological Control
Attempts at soybean seed treatment with endospores of Pasteuria thornei only reduced nematode abundance when applied at very hig densities and was less effective than abamectin (Confort and Inomoto, 2018)
Agrios, G. N. 2005. Plant Pathology, 5th Edition. Elsevier Academic Press. 922 pp
Andressa, C. Z., Machado, A. C. Z., Ferraz, L. C. C. B., and Inomoto, M. M. 2012 Pathogenicity of Pratylenchus brachyurus on cotton plants. Journal of Cotton Science 16:268-271
Back, M.A., Haydock, P.P.J. and Jenkinson, P., 2002. Disease complexes involving plant parasitic nematodes and soilborne pathogens. Plant Pathology, 51(6), pp.683-697.
Chitambar, J. J., Westerdahl, B. B., and Subbotin, S. A. 2018. Plant Parasitic Nematodes in California Agriculture. In Subbotin, S., Chitambar J., (eds) Plant Parasitic Nematodes in Sustainable Agriculture of North America. Sustainability in Plant and Crop Protection. Springer, Cham.
Corbett, D.C.M. 1976. Pratylenchus brachyurus. CIH Description of Plant-parasitic Nematodes Set 6:89. CIH, St. Albans, England
Confort, P.M. de S. and M. M. Inomoto. 2018. Pasteuria thornei, a novel biological seed treatment for Pratylenchus brachyurus control in soybean. Nematology 20:519-523.
Da Silva. R.A., M.A.S. Serrano, A.C. Gomes, D.C. Borges, A.A. de Souza, G.L. Asmus, M.M. Inomoto. 200f. Ocorr�ncia de Pratylenchus brachyurus e Meloidogyne incognita na Cultura do Algodoeiro no Estado do Mato Grosso. Fitopatol. Bras. 29:337.
Davis, E. L., and MacGuidwin, A. E. 2000. Lesion nematode disease. Plant Health Instructor DOI: 10.1094/PHI2000-1030-02.
Filipjev, I. N. 1936. On the classification of the Tylenchinae. Proceedings of the Helminthological Society of Washington 3:80-82.
Filipjev, I. N., and Schuurmans Stekhoven. 1941. A manual of agricultural helminthology. Leiden: Brill.
Godfrey, G.H., 1929. A destructive root disease of pineapples and other plants due to Tylenchus brachyurus n. sp. Phytopathology, 19, pp.611-629. Koen H, 1967. Notes on the host range, ecology, and population dynamics of Pratylenchus brachyurus. Nematologica, 13:118-24.
Lordello, L.G.E. 1986 Plant-parasitic nematodes that attack coffee. Pp 33-41 in Anon. Plant-parasitic nematodes of bananas, citrus, coffee, grapes and tobacco. Union Carbide Corp.
McGowan, J. B. 1978. The Lesion Nematode, Pratylenchus brachyurus, infecting citrus. Nematology Circular No. 42. Florida Dept of Agric. and Consumer Services, Division of Plant Industry.
McKenry, M.V. and Roberts, P.A. 1985. Phytonematology study guide on nematodes and nematicides. Univ. of Calif. Special Publ. #4045, 56 pgs.
Miranda, M.D., Favoreto, L.L.and Ribeiro, N.R.2010. Nematoides: um desafio constante. Funda� Brazil Boletim de Pesquisa Soja 2011 pp. 400-414.
Moody, E.H., Lownsbery, D.F., Ahmed, J.M. 1973. Culture of the root-lesion nematode Pratylenchus vulnus on carrot disks. J. Nematology 5:225-226.
Nemaplex UC Davis Nemabase . http://Nemaplex.ucdavis.edu. Accessed 10/12/23.
Rohrback, K. G., and Apt, W. J. 1986. Nematode and disease problems of pineapple. Plant Disease 70:81-87.
Roman, J., Triantaphyllou, A.C. 1969. Gametogenesis oand reproduction of seven species of Pratylenchus. J. Nematology 1:357-362.
Scheck, H.J. 2023. California Pest Rating Proposal for Pratylenchus brachyurus (Godfrey, 1929) Filipjev & Schuurmans-Stekhoven, 1941 smooth-headed lesion nematode. California Department of Food and Agriculture, Sacramento, California, USA,
Subbotin, S.A., Ragsdale, E.J., Mullens, T., Roberts, P.A., Mundo-Ocampo, M. and Baldwin, J.G., 2008. A phylogenetic framework for root lesion nematodes of the genus Pratylenchus (Nematoda): Evidence from 18S and D2-D3 expansion segments of 28S ribosomal RNA genes and morphological characters. Molecular phylogenetics and evolution, 48(2), pp.491-505.