{"id":2687,"date":"2016-10-05T16:16:11","date_gmt":"2016-10-05T23:16:11","guid":{"rendered":"http:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=2687"},"modified":"2024-04-26T10:45:33","modified_gmt":"2024-04-26T17:45:33","slug":"radopholus-similis-cobb-1893-thorne-1949","status":"publish","type":"post","link":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=2687","title":{"rendered":"Radopholus similis (Cobb, 1893) Thorne, 1949"},"content":{"rendered":"
\"1356104-burrowing-nematode-byMichaelMcClure-Univ-of-Ariz-bugwood\"<\/a><\/h5>\n
California Pest Rating for<\/strong><\/h5>\n
Radopholus similis<\/em><\/strong> (Cobb, 1893) Thorne, 1949<\/strong><\/h5>\n
(Burrowing Nematode)<\/strong><\/h5>\n
Pest Rating: <\/strong>A<\/h5>\n

 <\/p>\n

\n
PEST RATING PROFILE<\/strong><\/h5>\n
Initiating Event: \u00a0<\/strong><\/h5>\n

None.\u00a0 The current status and rating of Radopholus similis<\/em> is re-evaluated.<\/p>\n

\u00a0<\/strong>History & Status:<\/strong><\/h5>\n

Background<\/u><\/strong>:\u00a0 The burrowing nematode, Radopholus similis<\/em>, is one of the most economically important plant parasitic nematode in tropical and subtropical regions of the world.\u00a0 It is widespread in most banana-growing regions where it causes blackhead toppling disease or decline of banana. It is also known to cause declines of avocado, tea, coconut, citrus, and yellows (slow-wilt) disease of black pepper, and attacks several fruit, ornamentals, forest trees, sugarcane, coffee, weeds, vegetables, grasses, and weeds.<\/p>\n

Radopholus similis<\/em> has undergone several name changes over the past several years.\u00a0 In 1893, Cobb first described the nematode as Tylenchus similis<\/em> associated with a serious disease of bananas in Fiji. \u00a0From 1898 to 1915 the nematode was discovered in sugarcane in Hawaii, banana in Jamaica, and coffee in Java but described under different names which were later regarded as synonyms of T. similis<\/em>.\u00a0 In 1949, Thorne established the genus Radopholus<\/em> for the species originally belonging to Tylenchus<\/em>, and T. similis<\/em> became R. similis<\/em>.\u00a0 Radopholus similis<\/em> was known to have two biological races, a banana and citrus race.\u00a0 In 1984, the citrus race was elevated to species status and became known as R. citrophilus<\/em>, separate from R. similis<\/em> (Huettel, 1984).\u00a0 However, through molecular and morphological analyses, R. citrophilus<\/em> was determined to be similar to R. similis<\/em> and is now accepted as synonymous to the latter species (CABI, 2016; Kaplan & Opperman, 1997; Valette et al<\/em>., 1998). For regulatory purposes, the CDFA has always regarded R. similis<\/em> (sensu lato<\/em>) to include both banana and citrus races (Chitambar, 1997).<\/p>\n

Radopholus similis<\/em> is a migratory endoparasite of plant roots.\u00a0 The nematode develops from egg through four larval stages to adult male and female which reproduce sexually and parthenogenetically.\u00a0 Radopholus similis<\/em> completes its life cycle in 25 days at 25-28\u00b0C in coconut, 20-25 days at 24-32\u00b0C in banana, and 18-20 days at 24-27\u00b0C in citrus.\u00a0 The nematode species is able to complete its entire life cycle within the root cortex, however in adverse conditions, motile, vermiform larvae and adults may emerge from the roots and invade rhizosphere soils (EPPO, not dated; Tarjan & O\u2019Bannon, 1984).\u00a0 The number of nematodes present in soil and roots varies with soil temperature, texture, moisture, and season.\u00a0 On citrus, R. similis <\/em>is found at soil depths of 60-150 cm (DuCharme, 1967), and is more pathogenic to citrus in sandy soils than loam or sandy loam soils (O\u2019Bannon & Tomerlin, 1971).<\/p>\n

Hosts<\/strong>:\u00a0 Radopholus similis <\/em>has a very wide host range of more than 350 known hosts although the pathogenicity of the nematode is not known for all hosts (Ferris et al<\/em>., 2003).\u00a0 Main hosts include, Musa<\/em> sp. (banana), M. textilis<\/em> (Manila hemp), Musa x paradisiaca<\/em> (plantain), Citrus<\/em> spp. (citrus), Cocos nucifera<\/em> (coconut), Zingiber officinale<\/em> (ginger), palm, Persea americana<\/em> (avocado), Coffea arabica<\/em> (arabica coffee), C. canephora<\/em> (robusta coffee), Piper nigrum<\/em> (black pepper), Lycopersicum esculentum<\/em> (tomato), Daucas carota<\/em> (carrot),vegetables, trees, ornamentals, grasses, and weeds (CABI, 2016; Ford et al.,<\/em> 1960; Ferris, et al<\/em>., 2003).\u00a0 In California, agricultural crops of economic importance include citrus, strawberry, carrots, and ornamentals.<\/p>\n

Symptoms<\/strong>: <\/em>Above ground symptoms are non-specific and include yellowing, stunting, reduction in number and size of leaves and fruit, delay in flowering, and overall sparse foliage of orchard trees.\u00a0 Infected trees wilt more readily than healthy trees under adverse environmental conditions (Griffith & Koshy, 1990; Tarjan & O\u2019Bannon, 1984).\u00a0 Banana plants become uprooted and topple over, especially those burdened with fruit.\u00a0 Below ground symptoms include, brown to black lesions formed at the site of nematode penetration in citrus roots.\u00a0 These lesions coalesce to form cankers.\u00a0 A greater percentage of citrus feeder roots are destroyed below 75 cm than at 25-75 cm.\u00a0 In banana roots, dark red lesions appear on the outer root portion, penetrating throughout the cortex but not into the stele.\u00a0 Lesions may coalesce and girdle the root forming black, necrotic lesions which may extend into the corm (Gowen & Qu\u00e9n\u00e9herv\u00e9, 1990).\u00a0 Tender roots of coconut seedlings become spongy in texture and small, elongate orange lesions are formed in tender white roots.\u00a0 Lesions enlarge as rot sets in.\u00a0 Cracks in lesions may appears as lesions harden. Secondary and tertiary roots rot and slough off quickly on infestation (Griffith & Koshy, 1990).<\/p>\n

Damage Potential<\/strong>: <\/em>In Florida orchards, yield losses of 40-70% for oranges and 50-80% for grapefruit have been reported (DuCharme, 1968).\u00a0 Reduction in fruit production varies with age of the tree, citrus variety, farming practices and duration of the nematode infestation (CABI, 2016).\u00a0\u00a0 Avocado trees show spreading decline symptoms similar to citrus.\u00a0 Several indoor decorative plants can be severely affected (Ferris, 2003).\u00a0 Nurseries may suffer significant losses in production.<\/p>\n

Transmission<\/strong>: <\/em>Infested nursery stock, propagative planting materials, bare root stock, corms, rhizomes, suckers, seedlings, rooted and non-rooted cuttings, soil, infested-soil contaminated cultivation tools and containers, irrigation water.<\/p>\n

Brief update of detections in California<\/strong>:<\/em>\u00a0 The CDFA has been protecting California against the burrowing nematode since the early 1950s when the nematode pathogen was first found to cause spreading decline of citrus in Florida.\u00a0 In the years that followed, statewide surveys revealed several ornamental nurseries to be infested with Radopholus similis<\/em> and consequently, the nematode species was eradicated.\u00a0 In 1956, The Burrowing Nematode Exterior Quarantine (Sec. 3271) was established by CDFA to restrict the entrance of the pathogen from infested regions.\u00a0 In 1956, surveys of citrus and avocado orchards and ornamental nurseries, were conducted through the cooperative efforts of federal, state, and county agricultural commissioners.\u00a0 \u00a0These surveys resulted in no detection of R. similis<\/em> in CA. \u00a0In 1963, the burrowing nematode was detected in Anthurium<\/em> spp. in a nursery in San Mateo County.\u00a0 The plants were destroyed and the nematode was eradicated. From 1963-64, additional statewide surveys were conducted for Anthurium <\/em>spp.,<\/em> citrus, and avocado in orchards, nurseries, and residential properties adjacent to nurseries.\u00a0 No R. similis<\/em> was detected.\u00a0 In 1964, CDFA created the \u2018Burrowing Nematode Detection Program in California Nurseries\u2019 which terminated in 1994.\u00a0 Surveys continued in 1971, 2005-2009, and 2011 all which resulted in no detection of R. similis<\/em>.\u00a0 Intercepted plant shipments imported to California under the Burrowing Nematode Exterior Quarantine continue to be examined for the burrowing nematode.\u00a0 A noteworthy early detection of an established R. similis<\/em> population occurred in 1996 in a residential property in Huntington Beach. Consequently, the nematode was eradicated from the infested region (Chitambar, 2007). Since then, there have been no further detections of R. similis<\/em> established in California and the pathogen is not known to be present in California.<\/p>\n

Worldwide Distribution<\/u><\/strong>: The burrowing nematode is found worldwide in tropical and subtropical regions and occurs wherever bananas are grown.\u00a0 Worldwide distribution includes Asia<\/em>: Brunei Darussalam, India, Indonesia, Japan, Lebanon, Malaysia, Oman, Pakistan, Philippines, Singapore, Sri Lanka, Thailand, Yemen; Africa<\/em>: Benin, Burkino Faso, Burundi, Cameroon, Central African Republic, Congo, Congo Democratic Republic, C\u00f4te d’Ivoire<\/a>, East Africa, Egypt, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Madagascar, Malawi, Mauritius, Morocco, Mozambique, Nigeria, R\u00e9union<\/a>, Rwanda, Senegal, Seychelles, Somalia, South Africa, Sudan, Tanzania, Uganda, Zambia, Zimbabwe; North America<\/em>: Canada, Mexico, USA; Central America and Caribbean:<\/em> Barbados, Belize, Costa Rica, Cuba, Dominica, Dominican Republic, El Salvador, French West Indies, Grenada, Guadeloupe, Guatemala, Honduras, Jamaica, Martinique, Panama, Puerto Rico, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago, United States Virgin Islands, Windward Islands; South America<\/em>: Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Venezuela; Europe<\/em>: Belgium, France, Italy, the Netherlands, Slovenia; Oceania<\/em>: American Samoa, Australia, Cook Islands, Fiji, French Polynesia, Guam, Micronesia, New Caledonia, Niue, Norfolk, Palau, Papua New Guinea, Samoa, Solomon Islands, Tonga (CABI, 2016; EPPO, 2016).<\/p>\n

Official Control<\/u><\/strong>: Radopholus similis<\/em> is a quarantine, A-rated nematode pest under CDFA Sec. 3271. Burrowing and Reniform Nematode State Exterior Quarantine. Areas under quarantine include, the states of Alabama, Arkansas, Florida, Georgia, Hawaii, Louisiana, Mississippi, North Carolina, South Carolina, Texas, and the commonwealth of Puerto Rico.<\/p>\n

Radopholus similis<\/em> is listed in the \u2018Harmful Organism Lists\u2019 for 32 countries including, Antigua and Barbuda, Argentina, Bangladesh, Bermuda, Chile, China, European Union, French Polynesia, Georgia, Guatemala, Holy See (Vatican City State), Israel, Japan, Jordan, Madagascar, Mexico, Monaco, Morocco, Namibia, Nepal, Norway, Panama, Paraguay, San Marion, Serbia, South Africa, Taiwan, Tunisia, Turkey, United Arab Emirates, Uruguay, and Vietnam.\u00a0 Radopholus citrophilis<\/em> (synonym of R. similis<\/em>) is listed in the \u2018Harmful Organism Lists\u2019 for Antigua and Barbuda, Namibia, and South Africa; R. similis citrophilus<\/em> (synonym of R. similis<\/em>) is listed for Argentina, Brazil, European Union, French Polynesia, Grenada, Guatemala, Holy See (Vatican City State), Israel, Japan, Jordan, Monaco, Morocco, New Caledonia, San Marino, Serbia, Tunisia, Turkey, and Uruguay; Radopholus<\/em> spp. is listed for Australia, French Polynesia, and Nauru (USDA PCIT, 2016).<\/p>\n

California Distribution<\/u><\/strong>: Radopholus similis<\/em> is not established in California.<\/p>\n

California Interceptions<\/u><\/strong>: Since 1982 to September 2016, CDFA has made 182 detections of Radopholus similis<\/em> and 13 detections of Radopholus<\/em> sp. in incoming quarantine shipments of nursery and household plants at nurseries and border stations in California, of which only 16 detections of R. similis<\/em> and 0 detections of Radopholus<\/em> sp. were made during 2000-2016 (CDFA Pest and Damage Records Database)<\/em>.<\/p>\n

The risk burrowing nematode would pose to California is evaluated below.<\/p>\n

Consequences of Introduction:\u00a0<\/strong><\/p>\n

1) Climate\/Host Interaction:<\/strong> Evaluate if the pest would have suitable hosts and climate to establish in California. Score:<\/p>\n

-Low (1) not likely to establish in California; or likely to establish in very limited areas<\/p>\n

-Medium (2) may be able to establish in a larger but limited part of California<\/p>\n

– High (3)<\/strong> likely to establish a widespread distribution in California.<\/span><\/p>\n

Risk is High (3).\u00a0 <\/em><\/strong>California provides favorable climate and hosts for the establishment, increase, and widespread distribution of the burrowing nematode. <\/em>The nematode prefers coarse, sandy soils which are present in the Coachella Valley, the Bard Valley near Blythe, the Edison-Arvin citrus district of Kern County, and in streaks throughout the state. <\/em>Citrus and date palm, good hosts of the nematode, in the Coachella Valley are planted in soils subject to temperatures favorable to the development of the nematode.\u00a0 Host crops along the coastal areas, when planted in sandy soil, experience soil temperatures that can favor the development of the nematode if even for a few months.<\/em>\u00a0\u00a0<\/span><\/p>\n

2) Known Pest Host Range<\/strong>: Evaluate the host range of the pest:<\/p>\n

-Low (1) has a very limited host range<\/p>\n

-Medium (2) has a moderate host range<\/p>\n

– High (3)<\/strong> has a wide host range.<\/span><\/p>\n

Risk is High (3).\u00a0 <\/em><\/strong>Radopholus similis has a wide host range of over 350 host plants including citrus, strawberry, carrots, date palm, and ornamentals which are major hosts cultivated in California.<\/em><\/span><\/p>\n

3) Pest Dispersal Potential<\/strong>: Evaluate the dispersal potential of the pest:<\/p>\n

-Low (1) does not have high reproductive or dispersal potential<\/p>\n

-Medium (2) has either high reproductive or dispersal potential<\/p>\n

– High (3)<\/strong> has both high reproduction and dispersal potential.<\/span><\/p>\n

Risk is High (3).\u00a0 <\/em><\/strong>Radopholus similis has both high reproduction and dispersal potential.\u00a0 It is spread over long and short distances by infected plant roots, soil, planting stock, rooted and non-rooted cuttings, weeds, soil, nematode-contaminated cultivation tools, and containers, planting beds, irrigation and run-off water.<\/em><\/span><\/p>\n

4)\u00a0Economic Impact:<\/strong> Evaluate the economic impact of the pest to California using these criteria:<\/p>\n

A. The pest could lower crop yield<\/p>\n

B. The pest could lower crop value (includes increasing crop production costs)<\/p>\n

C. The pest could trigger the loss of markets (includes quarantines by other states or countries)<\/p>\n

D. The pest could negatively change normal production cultural practices<\/p>\n

E. The pest can vector, or is vectored, by another pestiferous organism.<\/p>\n

F. The organism is injurious or poisonous to agriculturally important animals.<\/p>\n

G. The organism can interfere with the delivery or supply of water for agricultural uses<\/p>\n

-Low (1) causes 0 or 1 of these impacts<\/p>\n

-Medium (2) causes 2 of these impacts<\/p>\n

– High (3)<\/strong> causes 3 or more of these impacts.<\/span><\/p>\n

Risk is High (3).\u00a0 <\/em><\/strong>The establishment of <\/em>Radopholus similis in California could result in lowered crop yield and value, increased crop production costs, loss of markets, imposition of domestic and international quarantines against California export plant commodities, and alteration of normal cultural practices, including delivery of irrigation water, to inhibit spread of the pathogen to non-infested sites.\u00a0 \u00a0\u00a0Citrus, strawberry, carrots, date palms, and ornamentals are some of the main industries that would be affected. \u00a0\u00a0Additionally, several other crops of lesser production in California are also at risk.<\/em><\/span><\/p>\n

5) Environmental Impact<\/strong>: Evaluate the environmental impact of the pest on California using these criteria:<\/p>\n

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.<\/p>\n

B. The pest could directly affect threatened or endangered species.<\/p>\n

C. The pest could impact threatened or endangered species by disrupting critical habitats.<\/p>\n

D. The pest could trigger additional official or private treatment programs.<\/p>\n

E. Significantly impacting cultural practices, home\/urban gardening or ornamental plantings.<\/p>\n

Score the pest for Environmental Impact:<\/p>\n

– Low (1) causes none of the above to occur<\/p>\n

– Medium (2) causes one of the above to occur<\/p>\n

– High (3)<\/strong> causes two or more of the above to occur.<\/span><\/p>\n

Risk is High (3).<\/em><\/strong> \u00a0\u00a0The establishment of <\/em>Radopholus similis in California could adversely impact the environment by destroying natural communities, critical habitats, significantly affect residential gardening and cultural practices thereby requiring additional official or private treatment programs. Given its wide host range several, agricultural and environmental communities are at definite risk of being impacted.\u00a0 These can include habitats of minor and major animal communities.<\/em><\/span><\/p>\n

Consequences of Introduction to California for Common Name:<\/strong>\u00a0 Score<\/strong><\/h5>\n

Add up the total score and include it here. (Score)<\/p>\n

Low = 5-8 points<\/p>\n

Medium = 9-12 points<\/p>\n

High = 13-15 points<\/p>\n

Total points obtained on evaluation of consequences of introduction to California = <\/span>15 (High)<\/span>.<\/strong><\/p>\n

6) Post Entry Distribution and Survey Information<\/strong>: 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)<\/p>\n

–Not established (0)<\/strong> Pest never detected in California, or known only from incursions.<\/span><\/p>\n

-Low (-1) Pest has a localized distribution in California, or is established in one suitable climate\/host area (region).<\/p>\n

-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.<\/p>\n

-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<\/p>\n

Evaluation<\/em><\/strong>:\u00a0 Radopholus similis is not established in California (0)<\/em><\/strong>.<\/em>\u00a0 In 1996, the nematode species was discovered in a residential area in Huntington Beach, California, however, due to the early detection and isolated nature of the incident, the infestation was successfully eradicated by the CDFA.\u00a0 Similarly, eradicative actions taken subsequent to the detection of the nematode species in imported nursery and household plant shipments, vigilant screening of plant materials grown in California soils and inspected for plant parasitic nematodes through CDFA\u2019s phytosanitary certification programs, USDA CAPS sponsored statewide surveys conducted by CDFA from 2005-2009 for 22 target nematode species including <\/em>R. similis, and all published studies to date on plant parasitic nematodes in California have never resulted in the detection of <\/em>R. similis.<\/span><\/p>\n

Final Score:<\/h5>\n

Final Score: <\/em><\/strong>\u00a0Score of Consequences of Introduction \u2013 Score of Post Entry Distribution and Survey Information =<\/strong> <\/span>15 (High)<\/span>.<\/strong><\/em><\/p>\n

Uncertainty: <\/strong><\/h5>\n

The damage potential and crop loss information on several hosts of this nematode species are yet to be determined.\u00a0 Nevertheless, based on the nematode\u2019s biology, diverse host range, and favorable climatic conditions that (historically have) allowed the pest to establish within California (and then be eradicated), more information gained on crop damage and losses can only further confirm the burrowing nematode as a pest of major economic importance within several regions of California.<\/em><\/p>\n

Conclusion and Rating Justification:\u00a0 <\/strong><\/h5>\n

Based on the evidence presented above, reniform nematode is definitely a pest of high risk to agricultural and environmental communities of California.\u00a0 The current given \u201cA\u201d pest rating of Radopholus similis<\/em> is duly justified and is herein, proposed to remain unchanged.\u00a0 <\/strong><\/p>\n

References:<\/strong><\/h5>\n

C<\/strong>ABI.\u00a0 2016.\u00a0 Radopholus similis<\/em> (burrowing nematode) datasheet (full). http:\/\/www.cabi.org\/cpc\/datasheet\/46685<\/a><\/p>\n

C<\/strong>hitambar, J. J.\u00a0 1997.\u00a0 A brief review of the burrowing nematode, Radopholus similis. <\/em>\u00a0California Plant Pest & Damage Report, California Department of Food and Agriculture, 16: 66-70.<\/p>\n

C<\/strong>hitambar, J. J. 2007.\u00a0 Status of ten quarantine \u201cA\u201d nematode pests in California.\u00a0 California Plant Pest & Damage Report, California Department of Food and Agriculture, 24: 62-75.<\/p>\n

D<\/strong>uCharme, E. P. 1967.\u00a0 Annual population periodicity of Radopholus similis<\/em> in Florida citrus groves.\u00a0 Plant Disease Reporter 51: 1013-1034.<\/p>\n

DuCharme, E. P. 1968. Burrowing nematode decline of citrus. A review. In:<\/em> Smart GC, Perry VG, eds. Tropical Nematology. Gainesville, USA: University of Florida Press, 20-37.<\/p>\n

E<\/strong>PPO.\u00a0 2016. \u00a0Radopholus similis <\/em>(RADOSI).\u00a0 PQR database.\u00a0 Paris, France: European and Mediterranean Plant Protection Organization.<\/p>\n

E<\/strong>PPO.\u00a0 Not dated.\u00a0 Data sheets on quarantine pests Radopholus citrophilus<\/em> and Radopholus similis<\/em>.\u00a0 Prepared by CABI and EPPO for the EU under Contract 90\/399003.\u00a0 https:\/\/www.eppo.int\/QUARANTINE\/data_sheets\/nematodes\/RADOSP_ds.pdf<\/a><\/p>\n

F<\/strong>erris, H., K. M. Jetter, I. A. Zasada, J. J. Chitambar, R. C. Venette, K. M. Klonsky, and J. Ole Becker.\u00a0 2003.\u00a0 Risk Assessment of plant parasitic nematodes. In <\/em>Exotic Pests and Diseases Biology and Economics for Biosecurity, D. A. Summer Editor. Iowa State Press. 265 p.<\/p>\n

F<\/strong>ord, H. W., W. A. Feder, and P. C. Hutchins.\u00a0 1960.\u00a0 Citrus varieties, hybrids, species and relatives evaluated for resistance to the burrowing nematode Radopholus similis<\/em>.\u00a0 Plant Disease Reporter 44:405.<\/p>\n

G<\/strong>owen, S., and P. Qu\u00e9n\u00e9herv\u00e9. \u00a01990. \u00a0Nematode parasites of bananas, plantains and abaca. In<\/em>: Luc, M., R. A. Sikora, J. Bridge, eds. Plant Parasitic Nematodes in Subtropical and Tropical Agriculture. Wallingford, UK: CAB International, 431-460.<\/a><\/p>\n

G<\/strong>riffith, R., P. K. Koshy. \u00a01990. \u00a0Nematode parasites of coconut and other palms. In:<\/em> Luc, M., R. A. Sikora, J. Bridge, eds. Plant Parasitic Nematodes in Subtropical and Tropical Agriculture. Wallingford, UK: CAB International, 363-386.<\/a><\/p>\n

H<\/strong>uettel, R. N., D. W. Dickson, and D. T. Kaplan.\u00a0 1984.\u00a0 Radopholus citrophilus<\/em> n. sp., a sibling species of Radopholus similis<\/em>.\u00a0 Proceedings of the Helminthological Society of Washington 51: 32-35.<\/p>\n

K<\/strong>aplan, D. T., and C. H. Opperman. \u00a01997. \u00a0Genome similarity implies that citrus-parasitic burrowing nematodes do not represent a unique species. Journal of Nematology, 29: 430-440. <\/a><\/p>\n

O<\/strong>\u2019Bannon, J. H., and A. T. Tomerlin.\u00a0 1970.\u00a0 Response of citrus seedlings to Radopholus similis in two soils.\u00a0 Journal of Nematology 3: 255-260.<\/p>\n

U<\/strong>SDA PCIT.\u00a0 2016.\u00a0 USDA Phytosanitary Certificate Issuance & Tracking System. September 27, 2016.\u00a0 https:\/\/pcit.aphis.usda.gov\/PExD\/faces\/ReportHarmOrgs.jsp<\/a>.<\/p>\n

V<\/strong>alette, C., D. Mouonport, M. Nicole, J. L. Sarah, and P. Baujard.\u00a0 1998.\u00a0 Scanning electron microscope study of two African populations of Radopholus similis<\/em> (Nematoda: Pratylenchidae) and proposal of R. citrophilus<\/em> as a junior synonym of R. similis<\/em>.\u00a0 Fundamental and Applied Nematology 21: 139-146.<\/p>\n

\n
Responsible Party: <\/strong><\/h5>\n

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.<\/p>\n

\n
Comment Period: \u00a0CLOSED<\/span><\/h5>\n

Oct 5\u00a0\u2013 Nov 19, 2016<\/p>\n

\n
Comment Format:<\/h5>\n

\u2666 \u00a0Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s)\u00a0being commented on, as shown below.<\/p>\n

Example Comment:\u00a0<\/strong><\/p>\n

Consequences of Introduction: \u00a01. Climate\/Host Interaction:\u00a0[Your comment that relates to \u201cClimate\/Host Interaction\u201d here.<\/em>]<\/p>\n

\u2666 \u00a0Posted comments will not be able to be viewed immediately.<\/p>\n

\u2666 \u00a0Comments may not be posted if they:<\/p>\n

Contain inappropriate language which is not germane to\u00a0the pest rating proposal;<\/p>\n

Contains defamatory, false, inaccurate, abusive, obscene, pornographic,\u00a0sexually oriented, threatening, racially offensive, discriminatory or illegal\u00a0material;<\/p>\n

Violates agency regulations prohibiting sexual harassment or other forms\u00a0of discrimination;<\/p>\n

Violates agency regulations prohibiting workplace violence, including threats.<\/p>\n

\u2666 \u00a0Comments may be edited prior to posting to ensure they are entirely germane.<\/p>\n

\u2666 \u00a0Posted comments shall be those which have been approved in content and posted to the\u00a0website to be viewed, not just submitted.<\/p>\n

\n

Pest Rating: <\/strong>A<\/h3>\n
\n

Posted by ls<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

California Pest Rating for Radopholus similis (Cobb, 1893) Thorne, 1949 (Burrowing Nematode) Pest Rating: A   PEST RATING PROFILE Initiating Event: \u00a0 None.\u00a0 The current status and rating of Radopholus similis is re-evaluated. \u00a0History & Status: Background:\u00a0 The burrowing nematode, Radopholus similis, is one of the most economically important plant parasitic nematode in tropical and … Continue reading Radopholus similis (Cobb, 1893) Thorne, 1949<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1117,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[27],"tags":[188,417],"class_list":["post-2687","post","type-post","status-publish","format-standard","hentry","category-nematodes","tag-nematodes","tag-radopholus-similis"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p5l8vQ-Hl","jetpack-related-posts":[{"id":1955,"url":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=1955","url_meta":{"origin":2687,"position":0},"title":"Nematodes","author":"Admin","date":"May 13, 2016","format":false,"excerpt":"(Plant Parasitic Nematodes) Nematodes (also called \u2018roundworms\u2019) are relatively small, multicellular, worm-like animals. They are found in almost every environmental niche imaginable, living free in soil, marine and freshwater habitats while feeding on bacteria, fungi, and nematodes, or as parasites of humans, insects, fish, larger animals and plants. Plant parasitic\u2026","rel":"","context":"In "Ratings"","block_context":{"text":"Ratings","link":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?cat=333"},"img":{"alt_text":"Nematodes montage","src":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Section3162\/wp-content\/uploads\/2016\/05\/nematodes-featured-image.jpg?fit=1038%2C588&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Section3162\/wp-content\/uploads\/2016\/05\/nematodes-featured-image.jpg?fit=1038%2C588&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Section3162\/wp-content\/uploads\/2016\/05\/nematodes-featured-image.jpg?fit=1038%2C588&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Section3162\/wp-content\/uploads\/2016\/05\/nematodes-featured-image.jpg?fit=1038%2C588&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":382,"url":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=382","url_meta":{"origin":2687,"position":1},"title":"Helicotylenchus multicinctus (Cobb, 1893) Golden, 1956","author":"Admin","date":"March 16, 2015","format":false,"excerpt":"California Plant Pest Rating for Helicotylenchus multicinctus (Cobb, 1893) Golden, 1956 Pest\u00a0Rating:\u00a0B \u00a0 PEST RATING PROFILE Initiating Event: None. An evaluation of the risk involved with the possible introduction and spread of H. multicinctus in California is documented herein and a permanent rating is proposed for the species. History &\u2026","rel":"","context":"In "Nematodes"","block_context":{"text":"Nematodes","link":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?cat=27"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":5547,"url":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=5547","url_meta":{"origin":2687,"position":2},"title":"Ambrosia Beetle | Euwallacea similis (Ferrari)","author":"Kyle Beucke","date":"June 28, 2018","format":false,"excerpt":"California Pest Rating for Ambrosia Beetle | Euwallacea similis (Ferrari) Coleoptera: Curculionidae: Scolytinae Pest Rating: A \u00a0 PEST RATING PROFILE Initiating Event: Euwallacea similis is currently Q-rated.\u00a0 A permanent pest rating proposal is required to support an official pest rating. History & Status: Background: \u00a0Adult female Euwallacea similis measure approximately\u2026","rel":"","context":"In "A-Rated"","block_context":{"text":"A-Rated","link":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?cat=669"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":4353,"url":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=4353","url_meta":{"origin":2687,"position":3},"title":"Tropical Whiteweed | Ageratum conyzoides L.","author":"Javaid Iqbal","date":"January 5, 2018","format":false,"excerpt":"California Pest Rating\u00a0 for Tropical whiteweed | Ageratum conyzoides L. Family: \u00a0Asteraceae Pest Rating: C |\u00a0\u00a0Proposed Seed Rating: None PEST RATING PROFILE Initiating Event: Tropical whiteweed was intercepted in Yolo county in October 2017 (PDR 570P066111862). It has not yet been rated.\u00a0A pest rating proposal is required to determine a\u2026","rel":"","context":"In "Weeds"","block_context":{"text":"Weeds","link":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?cat=7"},"img":{"alt_text":"map for Tropical whiteweed","src":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Section3162\/wp-content\/uploads\/2018\/01\/whiteweed-map-300x177.png?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":6389,"url":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=6389","url_meta":{"origin":2687,"position":4},"title":"Paratrichodorus spp. (Siddiqi 1974) and Trichodorus spp. (Cobb 1913)","author":"Heather.Martin","date":"September 4, 2019","format":false,"excerpt":"California Pest Rating for Paratrichodorus spp. (Siddiqi 1974) and Trichodorus spp. (Cobb 1913) Pest Rating: C DOWNLOAD PEST RATING Responsible Party: Heather J. Scheck, CDFA Primary Plant Pathologist\/Nematologist. 204 West Oak Ave, Lompoc, CA93463. 805-736-8050. plant.health[@]cdfa.ca.gov. *NOTE: You must be registered and logged in to post a comment. If you\u2026","rel":"","context":"In "C-Rated"","block_context":{"text":"C-Rated","link":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?cat=671"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":6906,"url":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?p=6906","url_meta":{"origin":2687,"position":5},"title":"Xiphinema americanum Cobb, 1913 American dagger nematode","author":"Heather.Martin","date":"February 27, 2020","format":false,"excerpt":"California Pest Rating for Xiphinema americanum Cobb, 1913 American dagger nematodePest Rating: C download pest rating *NOTE: You must be registered and logged in to post a comment. If you have registered and have not received the registration confirmation, please contact us at permits[@]cdfa.ca.gov. Posted by ka","rel":"","context":"In "C-Rated"","block_context":{"text":"C-Rated","link":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/?cat=671"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"_links":{"self":[{"href":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/index.php?rest_route=\/wp\/v2\/posts\/2687","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/index.php?rest_route=\/wp\/v2\/users\/1117"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2687"}],"version-history":[{"count":6,"href":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/index.php?rest_route=\/wp\/v2\/posts\/2687\/revisions"}],"predecessor-version":[{"id":4669,"href":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/index.php?rest_route=\/wp\/v2\/posts\/2687\/revisions\/4669"}],"wp:attachment":[{"href":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2687"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2687"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.cdfa.ca.gov\/Section3162\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2687"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}