Rev 12/16/2024
Chromadorea Rhabditida Tylenchina Tylenchoidea Pratylenchidae Pratylenchinae
Pratylenchus zeae Graham, 1951
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Lip region is generally low and flat; tail conical and rounded.
Nematode has short ventral overlap of esophagus.
Monovarial, uterus prodelphic.
Females are slender.
Ref: Subbotin et al., 2008.
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Wide.
C-rated pest in California Nematode Pest Rating System. (Scheck, 2024)
Migratory endoparasite.
All stages feed in the root cortex, never found in vascular tissues.
Extracts from the nematode show cellulolytic enzyme activity.
Besides graminaceous plants such as rice and maize, P. zeae has a wide host range that includes tobacco, sugarcane, cereals, .pepper, citrus, grape, lettuce, onion, peach and tomato.
Ecophysiological Parameters:
Like other Pratylenchus species, it has six life stages: egg, four juvenile stages, and adult. Since there are no males in this species, their are only females in this species; females reproduce by mitotic parthenogenesis; there is no fertilization and division of oogonia is by mitosis so that the somatic number of chromosomes is preserved throughout the reproductive process. The somatic chromosome number is 21-26 (Roman and Triantaphyllou, 1969)..
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 zeae survives the winter in infected roots or the soil as eggs, juveniles, or adults. During spring, when plant growth is active, eggs hatch tand root infection and feeding commence (Agrios, 2005; Chitambar et al., 2018; Scheck, 2024)
Stunting, wilting, premature yellowing of plants, root lesions. Pratylenchus zeae causes damage to plants through its migratory endoparasitic feeding habits. It may cause lesions tin the root cortex.h Lesions differ in appearance according to the level of infestation, the age of the lesion, and the host species. When the lesion breaks open, the cortex may slough off, leaving only the vascular cylinder. Secondary pathogens often enter these lesions, causing rot.
Damage to the root systems can lead to stunted growth, reduced plant vigor, chlorotic symptoms, defoliation, and a gradual decline in yield. The affected plants often appear in patches and are not uniformly distributed. (CABI, 2023).
Above-ground symptoms depend on the environmental conditions, and host tolerance. They are not diagnostic for lesion nematodes. Stunted and chloroticareas may a[ear in a field. The damage is often most severe in the center of these areas; symptoms diminish toward the edges and plants appear increasingly normal. 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 (Chitambar et al., 2018).
Reduce spread of the nematode in and between areas. Lesion nematodes are spread through the movement of contaminated soil and infected plant debris. They can be introduced to 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 with cultivation. Some nematodes may leave the root, enter the soil, and re-enter the root at a different site, causing a new infection. Lesion nematodes are usually only able to migrate slowly, 1-2 meters from the root zone they infect. However, in plantings where root grafts may occur, such as fruit trees, the nematodes may travel from plant to plant through roots (Davis and MacGuidwin, 2000
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Australasian Plant Pathology Society Factsheets on Plant-parasitic Nematodes (Prepared by Dr. Graham R. Stirling)
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Agrios, G. N. 2005. Plant Pathology, 5th Edition. Elsevier Academic Press. 922 pg
CABI Compendium. 2023. Pratylenchus zeae https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.43905 Accessed 12/12/23
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.
Davis, E. L., and MacGuidwin, A. E. 2000. Lesion nematode disease. Plant Health Instructor DOI: 10.1094/PHI2000-1030-02.
Fortuner R, 1976. Pratylenchus zeae. C.I.H. Descriptions of Plant-parasitic Nematodes, Set 6, No. 77:3 pp. Roman, J., Triantaphyllou, A.C. 1969. Gametogenesis oand reproduction of seven species of Pratylenchus. J. Nematology 1:357-362.
Scheck, H.J. 2024. California Pest Rating Proposal for Pratylenchus zeae Graham, 1951. Califrornia 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.