Entomology NEMATODES PARASITIZING SUGARCANE IN CUBA. J.P. O'Relly and J.R. PCrez MiliAn. Sugar Cane Research Institute, Academy of Sciences, Cuba

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1 NEMATODES PARASITIZING SUGARCANE IN CUBA J.P. O'Relly and J.R. PCrez MiliAn Sugar Cane Research Institute, Academy of Sciences, Cuba ABSTRACT Entomology Eight hundred and forty soil and root samples, representing all the sugarcane soils of Cuba, were examined. Eighty-four species of parasitic nematodes were found representing 4 superfamilies, 7 families and 17 genera. The most important species were Helicotylenchus dihysfera, H. eryfhrinae, H. refusus, Piufylenchus zeae, P. penefrans, P. sp.! Xiphinema diversicaudafum, X. americanum and Meloidogyne javanrca. Four new species parasitizing sugarcane were reported as a result of this survey. INTRODUCTION Almost a century had passed since the report made by Treubs (Java, 1885), when the existence of nematodes associated with sugarcane was first reported in Cuba. The first report, made by F. Pineda4 (1957), comprises species of the genera Meloidogyrze, Hoplolairnus and Radopholus which were found in plantations in the provinces of Habana and Matanzas. M. Fernhndezz (1970) published a compilation of the work carried out in Cuba by different specialists, including surveys conducted on nematodes associated with sugarcane. In his investigations 011 sugarcane, P. Krilov3 (1967) recorded more than 100 nematode species, 32 of which are parasitic. K.I. Borozdinh and J.P. O'Relly' ( ) found 55 genera during a survey carried out in cane areas all over the country. The genera most commonly encountered were Pratylenchus and Nelicotylenchus. In 1971 the Sugar Cane Research Institute of the Academy of Sciences undertook a more detailed study of nematode fauna in sugarcane. The results obtained from this study, with respect to parasitic fauna, are given in this paper. MATERIALS AND METHODS For this investigation 2-4 cane areas were selected in each province of the country, taking into consideration their soil-climatic dilferences (Table I). The study was conducted on 1-3 farms in each area. Each farm comprised 1-3 cane fields. Five points were chosen in each field from which samples of soil from the rhizosphere and roots were collected. Thus, a total of 840 samples (soil and roots) were processed from the 84 fields under study.

2 498 ENTOMOLOGY TABLE I. Number of fields surveyed in different regions of Cuba. Province Regions Number of fields Pinar del Rio San Crist6bal 6 Guines 3 Habana Mayabeque 3 Matanzas Jovellanos Jagiiey Col6n Girdenas Las Villas Caibari6n Sagua Santa Clara Cienfuegos Camaguey Fl6rida Santa Cruz Esmeralda Camagiiey 2 1 Oriente Mayari Holguin Manzanillo Puerto Padre Total regions and fields Nematodes were isolated by the Baermann method. For each extraction, samples of 20g of soil and log of roots were collected and allowed to stand for hours. Fixation of individuals was carried out with a 6% formaldehyde solution. For tenlporary preparations, a glycerine-water (1: 10) solution stained with methylene blue was used. Individual identifications were made in collections of about 100 nematodes. Where large numbers were involved, however, only 100 nematodes were identified, and the total population of each species was calculated on a percentage basis. RESULTS AND DISCUSSION Parasitic nematodes are represented in Cuba by two orders: Tylenchida and Dorylaimida, which are distributed into 4 superfamilies, 7 families, 4 subfamilies, 17 genera and 84 species. (Appendix 1).

3 APPENDIX 1. Species Provinces Ot Cg LV Mt Hb ;PR 1. Aphelenchoides asterocaudatus A. besseyi A. bicaudatus A. helophilus A. saprophilus A. sub-parietinas 9: A. subfenuis A. spp (1)" % A. spp (2)' A. spp (3)" A. spp (4)" Aphelenchus avenue Aph. eremitus 17. Criconemoides.sp. 18. Ditylenchus intermedius ~ D. myceliophagus D. sp (1)" D. sp (2)" f Helicot.~ lenchus dihystera H. egiptiensis H. erythrinae I H. californicus f H. canadiensis H. crenacauda H. lobus H. ~nulticintus f H. pseudorobustus 3 1. H. retusus 32. H. *reynosus n sp H. sacchari n sp H. varicaudatzis H. vu1ga;is Hoplolainzus indicus Longidorus elongatus 38. L. caespiticola 39. L. nir~ilai 40. L. tardicauda 41. L. spp (1)" 42. L. spp (2)" 43. Meloidogyne javanica 44. M.' spp,

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5 I For a better comprehension of the parasitic fauna found, nematodes have been grouped into genera, subfamilies and families. (Table 11). TABLE 11. Genera, subfamilies and families of nematodes. Order Superfamily Family Subfamily Genus Tylenchidae Tylet~chus Ditylet~clzlcs Trophurus Helicotyletzchus Tylenchidae Hoplolaiminae Hoplolairnus Tylenchida Tylenchoidea Rotylet~clius Pratylenchinae Praty ler~chus Radopho,us Heteroderidae Meloidogyt~e I Criconematidae Cricot~en~oides Paraty leticlius I1 Aphelenchoidea Aphelenchidae Aphelenchidae Apl~eler~c/roides Aphelet~cl~us Dorylaimoidea Dorylaimidae I Diphtherophorcidea I1 Dorylaimida Trichodoridae Trichodorus Family Tylenchidae. Subfamily Hoplolaimidae. This family is represented by three genera: Helicotylenchus, Hoplolaimus and Rotylenchus. Genus Helicotylenchus: Represented by root ectoparasites. It is widespread in Cuban cane areas and though great differences were found in the specific composition and behavior in the different regions (Map I), some characteristic symptoms ol their attack were detected, namely necrotic lesions and malformation of roots; total absence or a marked deficiency in the formation of rootlets, and poor crop growth. In spite of the fact that the damage was not assessed and that no attempts were made to confirm the real cause, it is assumed that the presence of these species may have had a direct or indirect influence.

6 502 ENTOMOLOGY FIGURE 1. Distribution of 'the most important species of the genus Helicotylenchus in sugarcane in Cuba. H. DIHYSTERA H H.ERYTHRINAE *Figures represent ~ / o or the most irnpurtnnt specter prescf H. RETUSUS ~n relalid" with the number of lields sampled. NOT FOUND FIGURE 2. Distribution of the important species of the genus Pratylenchus in sugarcane in Cuba. P. ZEAE i? PENETRANS P PRATENSIS I? SP $ Figures represent % of the lnost important species presenl ~n relation with [he number of fields sampled. FIGURE 3. Diffusion of the most important species of Helicotylenchus and Pratylenchrrs in sugarcane in Cuba. '3 H. RETUSUS P. ZEAE ll P PENETRANS

7 As may be seen in Appendix 1, 14 species were found, the most common, being: H. dihystera, H. erythrinae and H. retusus. The Matanzas province, with 10 species and the highest populations of the common species, (except for H. retusus, which was not encountered) seems to offer the most favorable conditions for the development of this genus (Map I).. Eight species were recorded in the province of Oriente, H. erythrinaea being the most widely spread, and H. retusus having the highest populations ( nematodes per 320 g of soil). In order of decreasing number of species, the rest of the provinces gave the following figures: Camagiiey 7, Las Villas 5, Habana 4 and Pinar 'del Rio 4 (Map 3). Two new species were reported among the total number pertaining to this genus: H. reynosus and H. sacchari. Genus Hoplolaimus: In Matanzas province only one species Hoplolairnus indicus was found. This genus is not of special interest for sugarcane when compared with Helicotylerzchus and some others. Genus Rotylenchus: Only 10 individuals of the species Rotylenchus reniformis were found in a root sample from the Oriente province. Hence, at present it is not considered an important sugarcane parasite. Subfamilies Pratylmchinae and Radopholinae: These are represented by two genera, Pratylenchus and Radopholus. The former is of widespread occurrence in the cane areas of our country, and has been found in roots and in the soil. Roots affected by Pratylenchus show well defined, dark brown necrotic lesions. They frequently exhibit malformations and crevices, and the cortex is easily detached from infested areas. When the population density is high plant growth is retarded. The largest number of species of the genus Pratylenchus were found in the provinces of Matanzas and Oriente, with 10 and 11, respectively. These species constitute a potential danger for the crop because of their variety and relatively wide distribution. Species common to all provinces by order of decreasing index of distribution, were P. zeae, P. penetmns, P. pratensis and P. sp. (Map 3). The highest occurrence of P. zeae was in the provinces of Matanzas and Oriente, where it was found in 72 and 74% of the samples respectively. This, coupled with a high average population (136 individual per log roots and 190 per 20g soil), and the large number of species recorded, indicated the existence of favorable overall conditions for the development of this genus in both provinces.

8 5 04 ENTOMOLOGY P. penetrans shows a higher rate of,distribution than P. zeae in Pinar del Rio - 67% -, equal in Habana - 56% -, and slightly lower in the rest of the provinces. P. pratensis and P. sp. occur at comparatively lower rates '(Map 2). In general, the rest of the species detected (Appendix 1) have a low rate of distribution. They are found in certain provinces and, in some cases, even in well defined areas within those provinces. Therefore, it is of interest to determine if their presence is associated with specific soil-climatic conditions. The only species of the genus Radopholus encountered was R. similis, which was found-in a sample collected in Oriente. It had also been found by 'Pineda4 in 1956, but there is evidence that it is scantily distributed in Cuban cane areas. Subfamily Tilenchinae: This is represented by four genera, Tylenchorhynchus, Tylenclzus, Ditylenchus and Trophurus. Genus Tylenchorhynchus: Low populations of _the species T. capitatus, T. brachycephalus, T. cilindricus, T. nudus, T. obscurus and T. maximus, were found distributed in all the provinces. Damage was not detected, which seems to indicate that they are of no significance to sugarcane. Genus Ditylenchus: Four species were found: D. intermedius, most widely spread in Habana, Matanzas and Oriente; D. miceliophagus, in Oriente and Las Villas and two which could not be identified. All four species show low populations in Oriente, but possible damage caused by them has not been assessed. Genus Tylenchus: This is widely distributed in the cane areas under study. It is represented by three species, namely: T. davainei, found in all provinces, T. filiformis, recorded only in Las Villas, T. exignus, which was encountered only in Oriente and T. sp., present in Oriente and Matanzas. Because of low populations and association with other genera, possible sugarcane damage by this genus was not determined. I Genus Trophurus: Two species werd recorded. T. sculptus recovered in Matanzas and the newly described T. roigi N. sp. in all provinces, with the exception of Pinar del Rio. In both cases, symptoms of damage in sugarcane were not observed, perhaps as a result of low populations. Subfamily Meloidogyninae: The genus Meloidogyne was represented by M. javanica and an unknown species of this genus. Larvae were not found in soil samples, but only in root nodules. As a result, an experiment was conducted in Matanzas on tomato (Lyco-

9 J.P. O'RELLY AND J.R. PEREZ MILIAN 505 persicum esculentum) as indicator plant, in order to establish more accurately their.possible distribution. Results revealed the presenc, of Meloidogyne in the cane areas of 17 sugarmills out of 18 under study, with an average distribution of 50.6% (present in 42 fields out of 83 surveyed). The study of sugarcane root nodules showed that they were structurally identical to those formed in tomato roots, but smaller in size. High populatioli densities of M. javanica, artificially inoculated into pots, have retarded cane growth. Field observations and laboratory trials indicate that it is capable of attacking all varieties. Subfamilies Criconematirzae and Paratylenchinae Two genera belonging to these subfamilies were found: Criconemoides and.paratylenchus. Only one species of Criconemoides was encountered in Matanzas, which was not identified. Two species of Paratylenchus, P. elaschistus and P. hamatus, were recorded. For both genera, distribution and population intensity were 1 low, which renders them innocuous to sugarcane. Superfamily Aphelenchoidea: The genus Aphelenchoides is included in this family. It consists of 14 species, of which only 10 have been identified. A. composticola and A. parietinus are the most widely spread species although, in general, their populations are low. Relatively higher populations were found in black soils. 3 I Family Aphelenchidae: Repr;esented by the genus Aphelenchus with its species: A. avenae and A. cremitus. The former is more widespread but, in spite of the fact that 206 individuals per 20g soil were found in Camaguey, populations of both of them are low, particularly in the rest of the provinces. Family Longidoridae: Larval Longidorus and Xiphinema, each with six species, were recorded. Genus Longidorus: Of the six species lound, two have not yet been classified. In general, they are not widely spread and populations are low. The highest number of species (five) has been recorded in Oriente (Appendix 1 ). Genus Xiphinema: As with Longidorus, six species have been found, two of which remain unidentified. Their distribution by provinces is also similar to that of Longidorus (Maps 4 and 5). Population densities, however, are higher in the eastern provinces, specially in the vicinity of CBndido Gonz6les sugar mill, Camaguey, where 25 individuals of X. americanum were found per 20g soil. One of the five species existing in Oriente is new: X. cubensis n. sp. (Appendix 1 ).

10 506 ENTOMOLOGY FTGURE 4. Distribution of species of genus Xiphitiema in sugarcane in Cuba. BX, AMERlCANUM Bx. DIVERSI( :AUDATUM CUBENSIS mx. mx. SR HX ENSICULIFERUM w I,?#-F~~u~cs represent ~ / o of the species in relation with the/ - / numhcr of fields sam pled. FIGURE 5. Diffusion of the most important species of Xiphirlerrra in sugarcane in Cuba. ax AMERICANUM OX DIVERSICAUDATUM HX CUBENSIS Hx SP DX ENSICULIFERUM.X NOT FOUND On account of their role as carriers of several types of virus, the species belonging to these two genera are significant in various crops. Consequently, though their effect on sugarcane is not yet defined, they are regarded as potentially dangerous in Oriente. Family Trichodoridae: Of this family, three species of the genus Trichodorus were recorded. All of them are present in Matanzas, two in Las Villas, one in Oriente and one in Pinar del Rio. Their distribution and population intensity being low, we do not have a well defined criterion with respect to potential damage to sugarcane. However, for the reasons listed for Xiphinema and Longidorus, representatives of this genus are considered to be relatively important. CONCLUSIONS The quantitative composition ol nematode populations in Cuban provinces is characterized by certain peculiarities. From the analyses conducted

11 on soil and root samples it appears that the highest numbers of nematodes were always found in samples collected in the provinces of Oriente, Camagiiey and Matanzas. Samples from the other provinces were distinguished by lower populations. The highest composition density- of parasitic nematode species was noted in Oriente and Matanzas, while in the rest of the provinces it was lower. Overall distribution in Cuba was characterized mainly by groups of species such as H. dihystera, N. erytlzrinae, F. zeae and P. sp. In various provinces it became obvious that damages observed in the root system of sugarcane were caused by parasitic nematodes, specially by the following species: H. retusus, P. zeae, X. eizsiculiferum, 1. erythrinae. These results have led us to direct our efforts towards the estimation of possible economic damage to the sugarcane crop in Cuba by the above mentioned parasitic species. REFERENCES 1. Borozdink, K.I. and D'Relly, J.P. (1969). Nematode fauna in sugarcane plantations in Cuba. Sugarcane series 27: 1-13 (in Spanish). 2. Fernhndez 'Diaz-Silveira, M. (1970). List of nematodes of Cuba. Revista de Agricultura. Aiio 111, I:81-82 (in Spanish). 3. Krilov, P.S. (1967). On the problem of disease fauna of sugarcane nematodes in Cuba. Revista del Laboratorio de Helmintologia, Vol. XVIII:56-58., 4. Pineda, F. (1959). Nematodes parasiting sugarcane in Cuba. Mens. Asoc. Tec. Azuc. de Cuba. 31~9-14 (in Spanish). 5. Treub, M. (1885). Onderzoekingen Over Sereh-Ziek Suikerriet gedaan in Stards Plantent te Buitenzorg. Meded, Batavia 2:l-39. NEMATODOS PARASITOS DE LA CAmA DE AZUCAR EN CUBA J.P. O'Relly y J.R. PBrez Mili6n RESUMEN Se analizaron 840 muestras de suelo y de raiz representativas de todos 10s suelos caieros de Cuba. Se encontraron 84 especies de nematodos parasitos pertenecientes a dos brdenes, 4 superfamilias, 7 familias y 17 generos. Las especies mas importantes son: Helicofylenchus dihystera, H. eryfhrinae, H. refusus, Prafylenchus zeae, P. penetrans, P. sp., Xiphinema diversicaudafum, X. americanum y Meloidogyne javanica. En este estudio se informa sobre cuatro nuevas especies parasitas de la caiia de azucar.