California Pest Rating for
Pratylenchus coffeae (Zimmermann) Filipjev & Schuurmans-Stekhoven
Pest Rating: B
PEST RATING PROFILE
Initiating Event:
None. The risk of introduction and establishment of Pratylenchus coffeae is evaluated and the current rating is reviewed.
History & Status:
Background: For long, Pratylenchus coffeae has been considered a complex group of several morphologically indistinguishable species sharing a wide range of morphological variability within the group and within a single species or populations of a single species. Historically, this has resulted in a loss of the true identity of the species, and the creation of several new species based on questionable differences. Consequently, the morphological identification of P. coffeae has been based on the species complex with its high variability and identified as P. coffeae sensu lato (latin: ‘in the broad/general sense’). Numerous studies have been reported on the taxonomy of P. coffeae to clarify its identity. Molecular and phylogenetic analyses of the species complex group have now enabled the distinction of P. coffeae sensu stricto (latin: ‘in the strict/true sense’) from other distinguished representatives of the group through the development of species-specific molecular diagnostic tests. Nevertheless, most reports on biology, ecology, geographical distribution, hosts, crop loss, and regulatory actions of the species are based on the species complex group of P. coffeae. This is also true for P. coffeae detected within California.
The true status of P. coffeae (sensu stricto) in California is not known and early records, based solely on morphological analysis of the species, may be dubious. Siddiqui et al. (1973) reported the detection of P. coffeae, from 1952-1972, in residential and nursery greenhouse environments in several northern and southern coastal counties and few northern and southern valley counties, and 1 commercial site in Los Angeles County. Much of their information was from University of California nematode distribution records, nematode detection records of certain County Agricultural Commissioner offices, and the CDFA Nematology Laboratory. Then, according to CDFA Nematode Detection Records, during the 1970s, P. coffee was infrequently detected in commercial soils in Glenn, Sonoma, and Merced counties. However, there is a paucity of information on these detections and their related sites that would allow confirmation. During the 1980s, P. coffeae was detected nine times in fruit tree nursery stock root samples submitted to CDFA for analysis and certification, and once in a plant root sample from a private residence in Riverside County. The species was detected in several incoming shipments of ornamental plants imported to California nurseries under the External Quarantine Burrowing and Reniform Nematode Program. From 1990-2016, the species was detected only three times, and again in fruit tree nursery stock, while several detections were made in imported nursery ornamental plants that were intercepted in California. Except for those few nursery stock detections, it is important to note that over the past 20 years or more, P. coffeae has not been found in California soils analyzed through CDFA’s nematode detection programs and surveys of agricultural production sites, nor has its in-state presence been reported from other sources.
Pratylenchus coffeae, the banana root nematode, is a migratory endoparasite of plant roots. Depending on the host infected, P. coffeae has a life cycle of 21-28 days at 25-30°C. The nematode is able to spend its entire life cycle within root tissue and all developmental stages, adult females, and males are found within roots and rhizosphere soils of host plants. Subsequently, infested plant root stock and associated soils are potential pathways for the transportation, introduction, and spread of this species. Also, in local situations, contaminated irrigation and run-off surface water from infested fields can help spread the species to non-infested areas. The species produces lesions on feeder roots and other underground plant parts as a result of its feeding. Damage caused by the nematode results in significant yield loss and reduction for several host plants. It is likely that P. coffeae originated in the Pacific Rim/Southeast Asia region (Burke et al., 2015) and was first discovered infesting coffee roots and damaging production. It is now distributed worldwide.
Hosts: Pratylenchus coffeae attacks a wide variety of plants of over 250 plant species belonging to almost all plant families. Hosts include Citrus spp., banana, plantain, coconut, coffee, cucurbits, fig, ginger, turmeric, cardamom, potato, maize, yams, caladium, vegetables, ornamentals, and weeds.
Damage Potential: Pratylenchus coffeae infects roots, tubers, corms, and rhizomes of host plants causing damage to the cortical tissue which results in development of lesions, weakened root systems, rot, stunting, death of plant, reduction in crop production and yield loss. Root lesions become avenues for secondary infections of fungi and bacteria. Crop losses up to 80% in Musa sp. (banana) are reported from South Africa (Sarah, 1989) and 60% production loss of plantains in Ghana (Burke, et al., 2015). In the United States, growth of citrus rootstock was reduced by 49-80% due to P. coffeae and fruit yields on rough lemon and sour orange rootstocks were reported 143% and 231% higher respectively, than trees infected with P. coffeae in the first bearing year, and 220% and 271% more in the second year (O’Bannon & Tomerlin, 1973).
Worldwide Distribution: Banana root nematode was originally discovered in Java, Indonesia. It is found worldwide, although distributed primarily in tropical and subtropical regions. Most reports record the occurrence of the species complex Pratylenchus coffeae sensu lato from Asia: Afghanistan, Bangladesh, Bhutan, Brunei Darussalam, China, India, Indonesia, Iran, Japan, Korea, Malaysia, Oman, Pakistan, Philippines, Sri Lanka, Papua New Guinea, Taiwan, Thailand, Turkey, Vietnam; Africa: Cameroon, Côte d’Ivoire, Ghana, Kenya, Madagascar, Malawi, Mauritius, Mozambique, Nigeria, Seychelles, South Africa, Swaziland, Tanzania, Uganda, Zambia, Zimbabwe; North America: Canada, Mexico, USA; Central America and Caribbean: Belize, Costa Rica, Cuba, Dominica, Dominican Republic, El Salvador, Grenada, Guadeloupe, Guatemala, Honduras, Jamaica, Martinique, Nicaragua, Panama, Puerto Rico, Trinidad and Tobago; Europe: Austria, Bulgaria, Italy, Slovenia, Spain; South America: Brazil, Chile, Colombia, Ecuador, French Guiana, Suriname, Venezuela; Oceania: Australia, Cook Island, Fiji, Kiribati, Niue, Palau, Papua New Guinea(CABI, 2014; Castillo & Vovlas, 2007; EPPO, 2014).
In the USA, Pratylenchus coffeae has been reported in Arkansas, California, Florida, Hawaii, North Carolina, and South Carolina (CABI, 2014; Castillo & Vovlas, 2007; EPPO, 2014).
Official Control: Pratylenchus coffeae is a phytosanitary risk in all tropical and subtropical countries (CABI, 2016). Currently, P. coffeae is a C-rated pathogen in California. The nematode species is on the ‘Harmful Organism Lists” for Argentina, Canada, Chile, French Polynesia, Indonesia, Madagascar, Morocco, New Caledonia, Timor-Leste, and Uruguay (USDA-PCIT, 2016).
California Distribution: The true presence and distribution of Pratylenchus coffeae in California is not known as identification was based primarily on the species complex group (see “Background”). However, from 1996 to May, 2016, P. coffeae was detected three times in CDFA’s Nursery Stock Nematode Certification Program: once in Los Angeles County (2002), once in Riverside County (1997), and once in Santa Barbara County (1998).
California Interceptions: Pratylenchus coffeae has been detected in several incoming shipments of ornamental plants imported to California nurseries under the External Quarantine Burrowing and Reniform Nematode Program.
This risk banana root nematode, Pratylenchus coffeae would pose to California is evaluated below.
Consequences of Introduction:
1) Climate/Host Interaction: Evaluate if the pest would have suitable hosts and climate to establish in California. Score:
– Low (1) Not likely to establish in California; or likely to establish in very limited areas.
– Medium (2) may be able to establish in a larger but limited part of California.
– High (3) likely to establish a widespread distribution in California.
Risk is Medium (2): Pratylenchus coffeae is likely to establish wherever its infected host is able to establish within California. However, even with this capability, and since the early 1970s, P. coffeae has not been reported from California’s agricultural crop production sites, nor is it known to be established widely within California. Therefore, a ‘medium’ risk is assessed for this category.
2) Known Pest Host Range: Evaluate the host range of the pest. Score:
– Low (1) has a very limited host range.
– Medium (2) has a moderate host range.
– High (3) has a wide host range.
Risk is High (3): Pratylenchus coffeae attacks a wide variety of plants of over 250 plant species belonging to almost all plant families. Citrus, fruit trees, and ornamentals are some of the main susceptible hosts of concern for California.
3) Pest Dispersal Potential: Evaluate the natural and artificial dispersal potential of the pest. Score:
– Low (1) does not have high reproductive or dispersal potential.
– Medium (2) has either high reproductive or dispersal potential.
– High (3) has both high reproduction and dispersal potential.
Risk is High (3): Pratylenchus coffeae is spread over long distances primarily through infested plant root stock and associated soils. Short-distance spread is through run-off irrigation water, infested and planting root stock, and movement of contaminated soil.
4) Economic Impact: Evaluate the economic impact of the pest to California using the criteria below. Score:
A. The pest could lower crop yield.
B. The pest could lower crop value (includes increasing crop production costs).
C. The pest could trigger the loss of markets (includes quarantines).
D. The pest could negatively change normal cultural practices.
E. The pest can vector, or is vectored, by another pestiferous organism.
F. The organism is injurious or poisonous to agriculturally important animals.
G. The organism can interfere with the delivery or supply of water for agricultural uses.
– Low (1) causes 0 or 1 of these impacts.
– Medium (2) causes 2 of these impacts.
– High (3) causes 3 or more of these impacts.
Risk is Medium (2): Pratylenchus coffeae infects roots, tubers, corms, and rhizomes of host plants causing reduction in crop yield and possible loss of markets.
5) Environmental Impact: Evaluate the environmental impact of the pest on California using the criteria below.
A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.
B. The pest could directly affect threatened or endangered species.
C. The pest could impact threatened or endangered species by disrupting critical habitats.
D. The pest could trigger additional official or private treatment programs.
E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.
Score the pest for Environmental Impact. Score:
– Low (1) causes none of the above to occur.
– Medium (2) causes one of the above to occur.
– High (3) causes two or more of the above to occur.
Risk is Medium (2): Pratylenchus coffeae could significantly impact cultural practices, home/urban gardening or ornamental plantings.
Consequences of Introduction to California for Pratylenchus coffeae:
Add up the total score and include it here. (Score)
-Low = 5-8 points
–Medium = 9-12 points
-High = 13-15 points
Total points obtained on evaluation of consequences of introduction to California = 12 (Medium).
6) Post Entry Distribution and Survey Information: Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included. (Score)
-Not established (0) Pest never detected in California, or known only from incursions.
-Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).
–Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.
-High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.
Evaluation is Medium (-2): The true presence and distribution of Pratylenchus coffeae in California is not known, however, from 1996 to May, 2016, P. coffeae was detected three times in CDFA’s Nursery Stock Nematode Certification Program: once in Los Angeles County (2002), once in Riverside County (1997), and once in Santa Barbara County (1998).
Final Score:
7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: (Score)
Final Score: Score of Consequences of Introduction – Score of Post Entry Distribution and Survey Information = 10 (Medium).
Uncertainty:
The status of Pratylenchus coffeae in California’s natural environment is not known. Also, not known is the true identity of members of the species complex in California.
Conclusion and Rating Justification:
Based on the evidence provided above the proposed rating for banana root nematode, Pratylenchus coffeae is B.
References:
Burke, M., E. H. Scholl, D. Mck. Bird, J. E. Schaff, S. Coleman, R. Crowell, S. Diener, O. Gordon, S. Graham, X. Wang, E. Windham, G. M. Wright, and C. H. Opperman. 2015. The plant parasite Pratylenchus coffeae carries a minimal nematode genome. Nematology 17:621-637. http://dx.doi.org/10.1163/15685411-00002901.
CABI. 2014. Pratylenchus coffeae (banana root nematode) basic datasheet. http://www.cabi.org/cpc/datasheet/43903.
Castillo, P. and N. Vovlas. 2007. Pratylenchus (Nematoda: Pratylenchidae): diagnosis, biology, pathogenicity and management. Hunt, D. J., and R. N. Perry (Series Eds).Nematology monographs and perspectives. Brill Leiden-Boston. 529 p.
Sarah, J. L. 1989. Banana nematodes and their control in Africa. Nematropica, 19:199-215.
Siddiqui, I. A., S. A. Sher, and A. M. French. 1973. Distribution of plant parasitic nematodes in California. State of California Department of Food and Agriculture Division of Plant Industry. 324 p.
USDA-PCIT. 2016. United States Department of Agriculture, Phytosanitary Certificate Issuance & Tracking System (PCIT). https://pcit.aphis.usda.gov/PExD/faces/ViewPExD.jsp .
Responsible Party:
John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: (916) 262-1110, plant.health[@]cdfa.ca.gov.
Comment Period: CLOSED
The 45-day comment period opened on Jun 29, 2016 and closed on Aug 13, 2016.
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Pest Rating: B
Posted by ls
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