{ "id": "coffee-nematodes", "url": "https://coffearium.org/entries/coffee-nematodes/", "license": "CC-BY-4.0", "title": "Nematodes", "summary": "Microscopic worms that feed inside coffee roots. Which root-knot and lesion nematodes matter where, how they weaken and kill trees, how seedlings spread them, and how rootstocks and clean nurseries hold them back.", "domain": "farm-management", "kind": "Pest", "stage": "farm", "topics": [ "science" ], "topicSections": {}, "lang": "en", "status": "verified", "reviewer": "Coffearium verification pass", "lastVerified": "2026-10-23T00:00:00.000Z", "updated": "2026-10-24T00:00:00.000Z", "added": "2026-10-23T00:00:00.000Z", "brief": [ "Root-knot nematodes (Meloidogyne) and root-lesion nematodes (Pratylenchus) are the main nematode pests of coffee; they live in the soil and feed inside the roots.1,2,3", "Infested trees grow poorly, yellow and decline; in a Guatemalan field trial, half of the ungrafted, untreated arabica plants had died after five years.3,5", "Infested nursery seedlings are an efficient way to carry nematodes to new fields; Brazil condemns a whole seedling lot if Meloidogyne is found.3,10", "Grafting arabica onto resistant rootstocks of C. canephora or C. liberica keeps trees productive on infested land.5,12,15", "In the field trials consulted for this entry, nematicides gave no significant yield gain.5,6" ], "quickFacts": [ { "label": "Main groups", "value": "Root-knot nematodes (Meloidogyne spp.); root-lesion nematodes (Pratylenchus spp.)" }, { "label": "Key root-knot species", "value": "M. exigua, M. incognita, M. paranaensis (Brazil); M. arabicida (Costa Rica); M. konaensis (Hawaii); M. hapla (Kenya)" }, { "label": "Key lesion species", "value": "P. coffeae; P. brachyurus (Brazil, mixed with root-knot species)" }, { "label": "Reported losses", "value": "10–35% by species, mostly Latin American data; up to 45% for M. exigua without control, as cited from a 2004 Brazilian field study" }, { "label": "Main spread", "value": "Infested seedlings, soil on machinery, water" }, { "label": "Rootstocks", "value": "Apoatã IAC 2258 (Brazil), Nemaya (Central America), Fukunaga and Meisner (Hawaii)" } ], "aka": [ "Coffee nematodes", "Plant-parasitic nematodes of coffee", "Root-knot nematodes", "Root-lesion nematodes" ], "linkTerms": [ "nematode", "nematodes", "root-knot nematode", "root-lesion nematode", "Meloidogyne", "Pratylenchus", "Meloidogyne exigua" ], "related": [ "coffea-canephora", "liberica-and-excelsa", "the-timor-hybrid", "ethiopian-landraces", "germination-and-seedlings", "coffee-leaf-rust", "coffee-berry-borer", "soils-for-coffee", "overbearing-and-dieback", "integrated-pest-management", "coffee-yields" ], "contested": [ "Size of the losses: a 2023 study summarises documented losses, mostly from Latin America, as 10–35% depending on species4; a 2013 study, citing a Brazilian field, gives up to 45% for M. exigua8; a 2023 Brazilian study cites 20–40% in infested areas.9 In the Guatemalan grafting trial, ungrafted plots yielded about one-third of grafted plots in 1995.5 The figures come from different species, sites and bases and are not comparable.", "How damaging M. exigua is: Brazilian sources treat it as a cause of large losses8,18; a 2020 Brazilian technical circular calls it less aggressive than M. paranaensis because it causes no structural damage to the roots.17" ], "corrections": [ { "date": "2026-10-24T00:00:00.000Z", "change": "The 2013 resistance study is now described as a study of the C. canephora cultivar Apoatã.", "reason": "The sentence sat under resistant arabica and read as a finding about Mex-1 arabica; the study tested a canephora cultivar. Found in the context audit of 24 Oct 2026." }, { "date": "2026-10-23T00:00:00.000Z", "change": "The 45% loss from M. exigua is now attributed to a 2013 study and a 2020 EPAMIG circular, both citing a 2004 field study (Rio de Janeiro state; \"when no control is applied\"), instead of being stated as one measured field.", "reason": "Silva et al. 2013 and EPAMIG CT-317 both cite Barbosa et al. 2004; neither measured the loss themselves." }, { "date": "2026-10-23T00:00:00.000Z", "change": "The 20–25% yield loss in Kona is no longer dated \"by 2001\"; it is given as a 2002 estimate cited in the 2012 paper.", "reason": "Aoki et al. 2012 date the 85% infection share to 2001 and cite the 20–25% estimate to Nelson et al. 2002." }, { "date": "2026-10-23T00:00:00.000Z", "change": "Hawaiian yields (0.05 and 1.93 kg per tree) are marked as estimated green coffee (20% of cherry weight); Guatemalan root counts (132 and 23 per gram) placed in plots without nematicide; solariser test described as 150 litres in an 8 cm deep box instead of an \"8 cm soil layer\"; Sudanese accessions removed from the 2001 resistance result.", "reason": "Wording of Schmitt et al. 2001 (Table 1), Villain et al. 2000 (Table 1), Uchôa et al. 2023 (Methods) and the Anzueto et al. 2001 abstract." }, { "date": "2026-10-23T00:00:00.000Z", "change": "T5296 is now identified as a Sarchimor (Timor Hybrid CIFC 832/2 × Villa Sarchi) with the World Coffee Research catalogue as source (new source 20).", "reason": "The Noir et al. 2003 abstract names T5296 only as an introgression line." } ], "sources": [ { "id": "s1", "title": "Economic importance, epidemiology and management of Pratylenchus sp. in coffee plantations", "authors": "Villain, L.", "year": 2008, "publisher": "In: Souza, R. M. (ed.), Plant-Parasitic Nematodes of Coffee, Springer, pp. 65–84", "url": "https://publications.cirad.fr/une_notice.php?dk=546256", "doi": "10.1007/978-1-4020-8720-2_5", "tier": "B", "tierNote": "Chapter in a specialist scientific book; abstract read on the CIRAD record.", "quote": "Nowadays, RLNs are being recognized as damaging to arabica and robusta coffees in Guatemala,", "quotes": [], "abstractOnly": true, "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s2", "title": "Breeding tools for durable resistance to nematodes (Meloidogyne spp.) of coffee varieties", "authors": "Lashermes, P.", "year": 2002, "publisher": "Plant Protection Science 38 (Special Issue 2), 717–720 (Proceedings of the 6th Conference of the EFPP, Prague)", "url": "https://pps.agriculturejournals.cz/pdfs/pps/2002/11/136.pdf", "tier": "B", "tierNote": "Conference proceedings paper without stated peer review.", "quote": "In Costa Rica, M. arabicida is responsible for severe dieback.", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s3", "title": "Root-knot nematodes, a growing problem for Conilon coffee in Espírito Santo state, Brazil", "authors": "Barros, A. F.; Oliveira, R. D. L.; Lima, I. M.; Coutinho, R. R.; Ferreira, A. O.; Costa, A.", "year": 2014, "publisher": "Crop Protection 55, 74–79", "url": "https://biblioteca.incaper.es.gov.br/digital/bitstream/123456789/2852/1/BRT-root-knotnematodes-lima.pdf", "doi": "10.1016/j.cropro.2013.10.004", "tier": "A", "quote": "Once the nursery is infested, seedlings turn into a very efficient way to disseminate root-knot nematodes.", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s4", "title": "Biocontrol-based strategies for improving soil health and managing plant-parasitic nematodes in coffee production", "authors": "Saikai, K. K.; Oduori, C.; Situma, E.; Njoroge, S.; Murunde, R.; Kimenju, J. W.; Miano, D. W.; Haukeland, S.; Coyne, D.", "year": 2023, "publisher": "Frontiers in Plant Science 14, 1196171", "url": "https://www.frontiersin.org/articles/10.3389/fpls.2023.1196171/full", "doi": "10.3389/fpls.2023.1196171", "tier": "A", "quote": "Coffee yield losses due to nematode infection is based mostly on data from Latin America and documented as between 10 to 35%, depending on species", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s5", "title": "Effect of grafting and nematicide treatments on damage by root-lesion nematodes (Pratylenchus spp.) to Coffea arabica L. in Guatemala", "authors": "Villain, L.; Molina, A.; Sierra, S.; Decazy, B.; Sarah, J. L.", "year": 2000, "publisher": "Nematropica 30(1), 87–100", "url": "https://journals.flvc.org/nematropica/article/download/69590/67250", "tier": "A", "quote": "The average mortality rate for untreated plants increased from 24% (range = 12-36%) in 1993 to 50% (25-76%) in 1995.", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s6", "title": "Potential for managing Meloidogyne konaensis on coffee in Hawaii with resistance and a nematicide", "authors": "Schmitt, D. P.; Zhang, F.; Meisner, M.", "year": 2001, "publisher": "Nematropica 31(1), 67–73", "url": "https://journals.flvc.org/nematropica/article/view/69614/67274", "tier": "A", "quote": "A yield benefit was not evident (P > 0.05) from the use of fenamiphos", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s7", "title": "Identification of a major gene (Mex-1) from Coffea canephora conferring resistance to Meloidogyne exigua in Coffea arabica", "authors": "Noir, S.; Anthony, F.; Bertrand, B.; Combes, M.-C.; Lashermes, P.", "year": 2003, "publisher": "Plant Pathology 52, 97–103", "url": "https://agritrop.cirad.fr/523151", "tier": "A", "quote": "Growing nematode-resistant coffee represents the most promising option for control of the pest.", "quotes": [], "abstractOnly": true, "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s8", "title": "Defense responses to Meloidogyne exigua in resistant coffee cultivar and non-host plant", "authors": "Silva, R. V.; Oliveira, R. D. L.; Ferreira, P. S.; Ferreira, A. O.; Rodrigues, F. A.", "year": 2013, "publisher": "Tropical Plant Pathology 38(2)", "url": "https://scielo.br/j/tpp/a/HPXNcjjNQRHDjDvBNvZH4jk/?lang=en", "tier": "A", "quote": "The resistance of coffee plants to Meloidogyne exigua is conferred by the gene Mex-1.", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s9", "title": "Evaluation of a prototype of soil thermal solarizer for control of gall nematode in the production of coffee seedlings", "authors": "Uchôa, F. P.; Vieira Junior, J. R.; Fernandes, C. F.; Rocha, R. B.; Espíndula, M. C.; Rudnick, V. A. S.; Silva, D. M.; Freire, T. C.; Sangi, S. C.; Mariobo, S. A. R.", "year": 2023, "publisher": "Coffee Science 18, e182014", "url": "https://www.alice.cnptia.embrapa.br/alice/bitstream/doc/1152410/1/ART-23006.pdf", "tier": "A", "quote": "Infected seeds and seedlings can introduce a new pathogen or increase its occurrence in areas of incidence", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s10", "title": "Nematological survey in coffee nursery in Espirito Santo state, Brazil", "authors": "Scarpi, M. C. F.; Gonçalves, Â. O.; Souza, A. F.; Camara, G. R.; Moraes, W. B.; Alves, F. R.", "year": 2021, "publisher": "Revista Ceres 68(2), 120–125", "url": "https://doaj.org/article/0051bad3855440a7afec3ec0b00b2773", "doi": "10.1590/0034-737x202168020005", "tier": "A", "quote": "Contaminated seedlings are an important and efficient agent for disseminating nematodes.", "quotes": [], "abstractOnly": true, "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s11", "title": "Kona coffee root-knot nematode sampling procedures (PD-114)", "authors": "Kawabata, A. M.; Myers, R.; Cho, A.; Nakamoto, S. T.", "year": 2018, "publisher": "University of Hawai‘i at Mānoa, College of Tropical Agriculture and Human Resources", "url": "https://www3.ctahr.hawaii.edu/oc/freepubs/pdf/PD-114.pdf", "tier": "A", "quote": "Ultimately, M. konaensis will reduce yield and cause tree death earlier than the normal lifespan of the tree.", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s12", "title": "Meisner, a coffee rootstock selection with increased tolerance to the Kona coffee root-knot nematode (FN-67)", "authors": "Kawabata, A.; Miyahira, M.; Yamauchi, N.; Myers, R.; Nakamoto, S. T.", "year": 2024, "publisher": "University of Hawai‘i at Mānoa, College of Tropical Agriculture and Human Resources", "url": "https://www3.ctahr.hawaii.edu/oc/freepubs/pdf/FN-67.pdf", "tier": "A", "quote": "One hundred percent of ‘Meisner’ grafted trees remained alive 13 years after planting", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s13", "title": "Resistance of semi-wild Coffea arabica L. from Ethiopia to a root-knot nematode, Meloidogyne konaensis", "authors": "Aoki, S.; Sipes, B.; Astorga, C.; Nagai, C.", "year": 2012, "publisher": "Nematropica 42(1), 131–136", "url": "https://ojs.test.flvc.org/nematropica/article/view/79592/76910", "tier": "A", "quote": "The Kona coffee root-knot nematode (Meloidogyne konaensis) infects coffee, reduces yield and shortens tree life.", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s14", "title": "Resistance to Meloidogyne incognita in Ethiopian Coffea arabica accessions", "authors": "Anzueto, F.; Bertrand, B.; Sarah, J. L.; Eskes, A. B.; Decazy, B.", "year": 2001, "publisher": "Euphytica 118, 1–8", "url": "https://link.springer.com/article/10.1023/A:1003712232325", "doi": "10.1023/A:1003712232325", "tier": "A", "quote": "Arabica varieties resistant to the nematode would avoid the need for grafting at altitudes of more than 800–1000 m.", "quotes": [], "abstractOnly": true, "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s15", "title": "Coffea canephora clones with multiple resistance to Meloidogyne incognita and M. paranaensis", "authors": "Fatobene, B. J. R.; Andrade, V. T.; Gonçalves, W.; Guerreiro Filho, O.", "year": 2019, "publisher": "Experimental Agriculture 55(3), 443–451", "url": "https://www.cambridge.org/core/journals/experimental-agriculture/article/abs/coffea-canephora-clones-with-multiple-resistance-to-meloidogyne-incognita-and-m-paranaensis/2CC6CE74F18D96AAF734F48B5FEB50C7", "doi": "10.1017/S0014479718000108", "tier": "A", "quote": "cultivation in infested areas has only been possible with the use of resistant C. canephora rootstocks", "quotes": [], "abstractOnly": true, "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s16", "title": "Cultivares de café resistentes aos nematoides-das-galhas no Brasil (Circular Técnica 312)", "authors": "Fatobene, B. J. R.; Salgado, S. M. L.; Ferreira, F. R. C.; Terra, W. C.", "year": 2020, "publisher": "EPAMIG (Empresa de Pesquisa Agropecuária de Minas Gerais)", "url": "https://livrariaepamig.com.br/wp-content/uploads/2023/02/CT-312.pdf", "tier": "B", "tierNote": "Technical guide of a state agricultural research company, in Portuguese.", "quote": "Única cultivar porta-enxerto resistente a nematoides atualmente disponível no Brasil", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s17", "title": "Danos provocados por nematoides-de-galhas às raízes do cafeeiro (Circular Técnica 317)", "authors": "Guimarães, N. M. R. B.; Salgado, S. M. L.; Bijsterveld, T. T.; Fatobene, B. J. R.; Alves, E.", "year": 2020, "publisher": "EPAMIG (Empresa de Pesquisa Agropecuária de Minas Gerais)", "url": "https://livrariaepamig.com.br/wp-content/uploads/2023/02/CT-317.pdf", "tier": "B", "tierNote": "Technical guide of a state agricultural research company, in Portuguese.", "quote": "M. exigua é menos agressiva ao cafeeiro pois não causa danos estruturais nas raízes", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s18", "title": "Field assessment of coffee (Coffea arabica L.) cultivars in Meloidogyne exigua-infested or -free fields in Rio de Janeiro State, Brazil", "authors": "Barbosa, D. H. S. G.; Souza, R. M.; Vieira, H. D.", "year": 2010, "publisher": "Crop Protection 29(2), 175–177", "url": "https://agris.fao.org/search/en/records/65de355e63b8185d9ca78f3d", "doi": "10.1016/j.cropro.2009.10.011", "tier": "A", "quote": "measures aimed to reduce the M. exigua population must be taken prior to planting", "quotes": [], "abstractOnly": true, "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s19", "title": "Morphological and molecular characterizations of Pratylenchus coffeae infecting Ming aralia and coffee in Vietnam", "authors": "Nguyen, H. D.; Nguyen, H. T.; Le, T. M. L.; Hoang, D. D.; Nguyen, T. D.; Trinh, Q. P.", "year": 2024, "publisher": "Helminthologia 61(1), 76–84", "url": "https://reference-global.com/article/10.2478/helm-2024-0004", "doi": "10.2478/helm-2024-0004", "tier": "A", "quote": "chlorotic leaves, stunted growth and root lesion in both hosts", "quotes": [], "abstractOnly": true, "accessed": "2026-10-23T00:00:00.000Z" }, { "id": "s20", "title": "T5296", "authors": "World Coffee Research", "publisher": "World Coffee Research, Arabica Coffee Varieties catalogue", "url": "https://varieties.worldcoffeeresearch.org/varieties/t5296", "tier": "A/B", "tierNote": "A for lineage and genetic group as catalogued; B for the history narrative (dates, transfers)", "quote": "was crossed with compact Villa Sarchi to create hybrid 361 (H361)", "quotes": [], "accessed": "2026-10-23T00:00:00.000Z" } ], "markdown": "## What coffee nematodes are\n\nNematodes are microscopic roundworms. Some live in the soil and feed on plant roots. On coffee, two groups do most of the damage: root-knot nematodes (*Meloidogyne*) and root-lesion nematodes (*Pratylenchus*).1,2,3\n\nThey live in the soil and enter the roots to feed.9 Root-knot nematodes form feeding sites inside the root.9 Lesion nematodes keep moving through the root and leave dead tissue behind.1\n\nBecause the damage is underground, it is easy to miss. A 2008 book chapter states that lesion nematodes were long underestimated, because their symptoms are not specific.1 In Hawaii, early infection is hard to diagnose.11\n\n## Which species, and where\n\nDifferent regions face different species. In Brazil the main root-knot species are *M. exigua*, *M. incognita* and *M. paranaensis*.2,16 According to a 2002 conference paper, *M. arabicida* causes severe dieback in Costa Rica.2 In Hawaii the pest is the Kona coffee root-knot nematode, *M. konaensis*.11,13 In 2023 a Kenyan study reported *M. hapla* on coffee in Kenya for the first time.4\n\nLesion nematodes damage arabica and robusta in Guatemala, El Salvador, Indonesia and Vietnam, among other countries, according to the 2008 chapter.1 *Pratylenchus coffeae* has been characterised from coffee in Vietnam.19 Often several species share one field.3\n\nSurveys show how common they can be. In Espírito Santo, Brazil, about 47% of sampled coffee plantations carried root-knot nematodes.3 In that survey *M. exigua* was found only on arabica, and *M. incognita* mostly on robusta (conilon).3\n\n## What they do to the tree\n\nThe roots show the damage first. *M. exigua* forms small, rounded galls on the fine roots.3,17 *M. incognita* and *M. paranaensis* thicken the roots unevenly, often without typical galls, and the root bark peels.3 *M. paranaensis* also cracks and destroys roots.17 Lesion nematodes cause lesions: patches of dead tissue (necrosis).1,19\n\nDamaged roots take up less water and fewer nutrients.8 Above ground the trees are stunted and yellow, and they look short of nutrients.3,19 In Hawaii, badly infested trees wilt, drop flowers and fruit, and die back.11 In the end, trees can die.11,16\n\n
\n
\n
    \n
  1. Yellowing, stunted crown. Infested trees grow poorly and their leaves yellow.3,19
    2. \n
  2. Rounded galls. Small galls on the fine roots, typical of M. exigua.3,17
    3. \n
  3. Thickened, cracked roots. Uneven swelling, cracks and peeling bark, as with M. incognita and M. paranaensis.3,17
    4. \n
  4. Lesions. Patches of dead tissue left by root-lesion nematodes (Pratylenchus).1,19
    5. \n
  5. Few feeder roots. In Hawaii, severely infested trees have fewer healthy feeder roots.11
    6. \n
  6. Arabica scion. The productive top of a grafted plant.12
    7. \n
  7. Graft union. Seedlings are joined by a cleft or splice graft.12
    8. \n
  8. Resistant rootstock. A root system of C. canephora or C. liberica that limits nematode damage.5,12,16
    9. \n
\n
Left, an ungrafted arabica plant with nematode damage; right, an arabica scion grafted onto a resistant rootstock. Point at a number or its name to highlight it. Schematic, not to scale.
\n
\n\n## How much crop is lost\n\nLosses differ by species and site.4,8 A 2023 study summarises documented losses at 10–35%, mostly from Latin American data.4 A 2013 study and a 2020 Brazilian technical circular, both citing a 2004 field study, report losses of up to 45% from *M. exigua*: the study in a plantation in Rio de Janeiro state, the circular where no control is applied.8,17\n\nSome trials measured the damage directly. In a Guatemalan trial with lesion nematodes, ungrafted plots yielded about one-third of grafted plots in 1995.5 Half of the ungrafted, untreated plants had died by then.5 In Hawaii, *M. konaensis* cut Kona coffee yields by an estimated 20–25%, according to a 2012 paper citing a 2002 estimate.13\n\nData from Africa and Asia are thin. A 2023 Kenyan study notes that damage levels in its region are largely undocumented.4\n\n## How they spread\n\nNematodes can move through the soil to new roots.11 People carry them much further. Once a nursery is infested, its seedlings spread root-knot nematodes efficiently.3,10 Soil on machinery and running water also carry them.3,16\n\nFor this reason, Brazil regulates seedlings. Under a 2012 federal rule, finding *Meloidogyne* in one plant condemns the whole seedling lot, which must be destroyed.10 In a 2021 survey of nurseries in Espírito Santo, *Meloidogyne* was still found.10\n\n## How producers manage them\n\nManagement starts before planting.16,18 Brazilian guidance advises testing soil and roots to identify the species first.16\n\n**Clean seedlings.** Producers plant nematode-free seedlings and avoid planting below infested blocks.3 Nurseries can heat their substrate. In a 2023 Brazilian test, solar heating to 60 °C for 45 minutes eliminated *M. incognita* from inoculated soil.9\n\n**Resistant rootstocks.** An arabica scion is grafted onto the roots of a resistant species. In Brazil the robusta rootstock Apoatã IAC 2258 is used; in Central America, Nemaya.13,16 In Hawaii, rootstocks of *C. liberica* are used.12 Robusta rootstocks are not adapted to high altitudes.2,14\n\n**Resistant arabica varieties.** Some arabica varieties resist certain species. Some lines from the Timor Hybrid carry a robusta gene against *M. exigua*.7,20 Semi-wild arabica from Ethiopia is a further source of resistance.13,14\n\n**Nematicides.** In the field trials consulted for this entry, nematicides gave no significant yield gain.5,6 We describe their use; we do not recommend products. Integrated pest management covers how these tools combine across pests.\n\n\n\n## Parasitism in the root\n\n**Root-knot nematodes.** *Meloidogyne* species parasitise the roots and form feeding sites there.9 Researchers count their eggs and second-stage juveniles (J2) in roots and soil.9 Galls are the clearest response of the host plant, and they hamper the uptake of water and nutrients.8\n\nThe species differ in the damage they cause. In a greenhouse study reported in a 2020 technical circular of a Brazilian state research company, *M. exigua* formed rounded galls on new roots.17 *M. paranaensis* thickened new roots with lengthwise cracks and destroyed roots of seedlings.17 The authors judge *M. exigua* the less aggressive of the two, because it causes no structural damage.17 In the Espírito Santo survey, roots with *M. incognita* or *M. paranaensis* showed irregular thickening without typical galls.3 Some conilon areas showed root damage without any symptoms above ground.3\n\n**Root-lesion nematodes.** *Pratylenchus* species are migratory and cause non-specific root necrosis, according to a 2008 chapter.1 In Vietnam, *P. coffeae* was associated with chlorotic leaves, stunted growth and root lesions.19 In the Espírito Santo survey, *P. brachyurus* occurred together with a root-knot species in 71.4% of infested samples.3\n\n## Distribution in detail\n\n| Species | Where reported (sources consulted) | Notes |\n|---|---|---|\n| *M. exigua* | Brazil2,3,16; Latin America widely7 | Only on arabica in Espírito Santo; 23.8% of properties3 |\n| *M. incognita* | Brazil2,3; Guatemala14 | 21% of properties in Espírito Santo, 92% of them robusta3 |\n| *M. paranaensis* | Brazil2,3 | 4.7% of properties, northern Espírito Santo only3 |\n| *M. arabicida* | Costa Rica2 | Severe dieback (conference paper)2 |\n| *M. konaensis* | Hawaii, United States11,12 | Most Kona farms; also Ka‘ū12 |\n| *M. hapla* | Kenya4 | First report on coffee in Kenya (2023)4 |\n| *Pratylenchus* spp. | Guatemala, El Salvador, Indonesia, Vietnam1 | *P. coffeae* characterised from Vietnam19 |\n| *P. brachyurus* | Brazil3 | Mixed with root-knot species3 |\n\nIn Brazil, a 2020 technical circular reports root-knot nematodes in arabica areas of Minas Gerais, São Paulo and Paraná, and in robusta areas of Espírito Santo and Rondônia.16 In Rondônia, *M. incognita* was the most frequent species in recent nursery and field detections.9 In Hawaii, *M. konaensis* had not been found in Hilo, Hāmākua or on the other islands as of 2024.12 No global distribution list dated 2026 was consulted for this entry.\n\n## Measured damage and yield loss\n\n**Guatemala, lesion nematodes.** A five-year trial on the southern slope of the Atitlán volcano, at 900 m, compared Caturra on its own roots with Caturra grafted onto seedling *C. canephora*.5 In 1995 the grafted plots yielded 16,000 kg of coffee berries per hectare against 5,300 kg for ungrafted plots.5 That is about one-third (our calculation). In plots without nematicide, ungrafted roots held 132 nematodes per gram of root that year, grafted roots 23.5 The most heavily infested ungrafted plots yielded 12 times less than the least infested.5\n\n**Hawaii, root-knot nematodes.** In a trial with *M. konaensis*, the arabica cultivar Guatemala on its own roots yielded an estimated 0.05 kg of green coffee per tree in 1995 without nematicide (green coffee estimated as 20% of cherry weight).6 Grafted onto *C. dewevrei* (the name used in the paper), it yielded an estimated 1.93 kg.6 Yields of Guatemala on its own roots fell by about 45% in the second year.6 In a 13-year trial at the Kona Research Station, 81% of non-grafted Kona Typica trees died; all trees grafted onto the Meisner rootstock survived.12\n\n**Brazil, M. exigua.** A 2010 field study in Rio de Janeiro state found that a high nematode population drastically reduced growth and yield.18 Its authors recommend that resistant cultivars be planted only after the population has been reduced, to avoid large losses.18\n\n
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Share of plants that died in two field trials on nematode-infested land: Guatemala (lesion nematodes, after five years) and Kona, Hawaii (M. konaensis, after 13 years). Data: Villain et al. 2000; Kawabata et al. 2024.5,12
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\n\n## Nurseries and seedling rules\n\nA 2023 Brazilian study notes that infected seeds and seedlings can bring nematodes into new areas.9 Until 1980, methyl bromide was the main way to disinfest substrate for coffee seedlings; the study reports that its use was later prohibited because of risks to the environment and health.9\n\nThe same study tested a solar heater that warms the soil from above and below. Soil inoculated with *M. incognita* (150 litres, in an exchanger box 8 cm deep) was held at a minimum of 60 °C.9 After 45 minutes, a bioassay with susceptible robusta seedlings over 180 days found the nematode eradicated.9 The authors recommend 60 minutes as a safety margin.9\n\nRegulation targets the seedlings themselves. Brazil’s Normative Instruction No. 35 of 2012 condemns a whole seedling lot if *Meloidogyne* is found in a single plant, as reported in a 2021 study.10 Under a 2016 ordinance, the plant health agency of Rondônia state (IDARON) requires laboratory analysis of nursery seedlings for nematodes.9 Raising and handling seedlings is covered in germination and seedlings.\n\n## Rootstocks and grafting\n\nGrafting onto resistant rootstocks is described as the best short-term option in a 2002 conference paper.2 A 2019 study from Brazil states that in infested areas, arabica cultivation has only been possible on resistant *C. canephora* rootstocks.15\n\n| Rootstock | Species | Where used | Reported resistance |\n|---|---|---|---|\n| Apoatã IAC 2258 | *C. canephora* | Brazil | *M. exigua*, *M. incognita*, *M. paranaensis*16 |\n| Nemaya | *C. canephora* (hybrid within the species) | Central America | Several root-knot species13 |\n| Fukunaga | *C. liberica* var. *dewevrei* | Hawaii (released 2001) | Tolerant to *M. konaensis*12 |\n| Meisner | *C. liberica* | Hawaii | Tolerant to *M. konaensis*12 |\n\nAccording to a 2020 Brazilian technical circular, Apoatã IAC 2258 was the only nematode-resistant rootstock cultivar available in Brazil.16 New *C. canephora* clones resistant to both *M. incognita* and *M. paranaensis* were selected in a 2019 study.15 In Hawaii, the extension service considers grafting the only practical long-term solution once the nematode is established.12 Grafting on Meisner did not lower cup quality in its trial.12\n\nRootstocks have limits. Robusta is not adapted to high altitudes, so resistant arabica would avoid grafting above about 800–1,000 m, according to a 2001 study.14 Liberica as a rootstock is discussed in liberica and excelsa, where study results differ.\n\n## Resistant arabica\n\n**Mex-1.** A single major gene, *Mex-1*, from *C. canephora* gives resistance to *M. exigua* in arabica.7,8 It was mapped in a cross between the introgression line T5296 and a susceptible accession.7 T5296 is a Sarchimor, catalogued as Timor Hybrid CIFC 832/2 × Villa Sarchi.20 Its expression appeared incompletely dominant, and 14 linked molecular markers were found.7 A 2013 study of the resistant *C. canephora* cultivar Apoatã concludes that its resistance involves a set of constitutive and induced defence responses, not only a hypersensitive reaction.8\n\n**Ethiopian accessions.** Tested against a Guatemalan isolate of *M. incognita*, 40% of the semi-wild Ethiopian arabica accessions tested were fully resistant.14 The reaction to a Brazilian isolate was similar.14 Resistance was dominant, controlled by one gene or two complementary genes depending on the cross.14 In Hawaii, all but one of the Ethiopian accessions tested were resistant to *M. konaensis*.13 The material is described in Ethiopian landraces.\n\n**Cultivars.** According to a 2020 Brazilian technical circular, Catiguá MG 3, IAPAR 59 and IAC 125 RN resist *M. exigua*, and IPR 100 and IPR 106 resist *M. paranaensis* and *M. incognita*.16 The circular advises against cultivars described only as tolerant, because nematodes still multiply on them.16\n\n## Biological and chemical control\n\n**Biological control.** In a 2020–2022 field trial in Kiambu County, Kenya, two fungi were drenched around arabica trees: *Trichoderma asperellum* and *Purpureocillium lilacinum*.4 After 12 months, *M. hapla* numbers in the roots had fallen significantly; numbers in the soil had not.4 Yield was not measured.4 The authors estimate the product cost at USD 23.43 per tree over the two years.4 No study consulted for this entry measured a yield gain from biological control.\n\n**Chemical control.** In the Guatemalan trial, terbufos reduced nematode numbers only in the first year.5 It lowered the death rate of ungrafted plants but did not raise yield significantly on any rootstock.5 In Hawaii, fenamiphos gave no significant yield benefit, and its cost exceeded the return.6 As of 2024, the nematicides available to Hawaiian producers give limited suppression.12 A 2002 conference paper describes nematicides as costly and environmentally risky, and their use as declining.2 No regulator’s list of approved or banned coffee nematicides was consulted for this entry; the status differs by country.\n\n## Reference values\n\n| Parameter | Value reported | Source |\n|---|---|---|\n| Yield loss, documented range | 10–35% by species, mostly Latin American data | Saikai et al.4 |\n| Yield loss, *M. exigua*, no control | Up to 45% (Rio de Janeiro, Brazil; cited from a 2004 study) | Silva et al.8; EPAMIG17 |\n| Yield loss, Kona, Hawaii | An estimated 20–25% (2002 estimate, cited in 2012) | Aoki et al.13 |\n| Yield, grafted vs ungrafted (Guatemala, 1995) | 16,000 vs 5,300 kg coffee berries/ha | Villain et al.5 |\n| Plant deaths, ungrafted, untreated (Guatemala) | 24% (1993) to 50% (1995) | Villain et al.5 |\n| Plant deaths, ungrafted, terbufos (Guatemala) | 4.5% (1993) to 23% (1995) | Villain et al.5 |\n| Plant deaths, grafted (Guatemala) | 6% at the end of the trial | Villain et al.5 |\n| Plant deaths after 13 years (Kona) | 81% non-grafted; 0% on Meisner | Kawabata et al.12 |\n| Yield, Guatemala cultivar (Hawaii, 1995) | Estimated 0.05 kg green coffee/tree own-rooted; 1.93 kg grafted (20% of cherry weight) | Schmitt et al.6 |\n| Substrate heat treatment (nursery) | Minimum 60 °C for 45 min eradicated M. incognita; 60 min advised | Uchôa et al.9 |\n| Plantations infested (Espírito Santo) | About 47% | Barros et al.3 |\n\n## Open questions\n\n- **Losses outside Latin America.** Damage data for Africa are largely lacking, according to a 2023 Kenyan study4; no measured loss for Asian robusta was consulted for this entry.\n- **Species identity.** In the Guatemalan trial the lesion nematode species was still being identified5; a 2002 paper reports unidentified root-knot populations in El Salvador and Guatemala.2\n- **Biological control in yield terms.** The Kenyan fungus trial reduced nematodes in roots but did not measure yield.4\n- **Durability of resistance.** No study consulted for this entry tested whether *Mex-1* or rootstock resistance breaks down over time.\n- **Damage thresholds.** No study consulted for this entry gives a nematode density at which control pays.\n\n## Key studies\n\n
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Villain et al., 2000 – Grafting against lesion nematodes in Guatemala. Followed Caturra on its own roots and on robusta rootstock for five years at 900 m, with and without a nematicide. Grafted plots carried far fewer nematodes, yielded about three times more in 1995 and lost few plants, while half of the ungrafted, untreated plants died.

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Nematropica 30(1), 87–100 · journals.flvc.org

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Noir et al., 2003 – The Mex-1 gene. Crossed the resistant introgression line T5296 with a susceptible arabica and followed resistance to M. exigua in the offspring. A single major gene from robusta controlled it, and linked markers allow early selection of resistant seedlings.

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Plant Pathology 52, 97–103 · agritrop.cirad.fr

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Barros et al., 2014 – Root-knot nematodes in Espírito Santo. Surveyed 172 properties in a Brazilian state where both arabica and conilon are grown. About half of the plantations were infested, the species differed by coffee type, and the authors identify infested nurseries as an efficient route of spread.

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Crop Protection 55, 74–79 · doi:10.1016/j.cropro.2013.10.004

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Saikai et al., 2023 – Fungi against root-knot nematodes in Kenya. Applied two soil fungi to mature arabica fields for two years. Root-knot nematodes in the roots fell significantly, but soil numbers did not, and yield was not measured.

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Frontiers in Plant Science 14, 1196171 · doi:10.3389/fpls.2023.1196171

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Kawabata et al., 2024 – The Meisner rootstock in Kona. Compared arabica grafted onto several rootstocks with non-grafted trees for 13 years on land infested with M. konaensis. Every tree on Meisner survived, while 81% of the non-grafted trees died.

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University of Hawai‘i CTAHR, FN-67 · ctahr.hawaii.edu

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