Rhynchophorus palmarum, the palm weevil, has been reported as a pest of palms and sugarcane plants. The Red Ring Disease is an infectious plant disease caused by nematodes. The etiological agent, Bursaphelencus (Rhadinaphelencus) cocophilus (Nematoda: Aphelenchoididae), completes its life cycle within 9 to 10 days inside the palm tree. The main symptom is a permanent wilting of the plant aerial parts. Previous studies stated that B. cocophilus cohabits with other nematodes the gut of R. palmarum. The aim of this study is to identify nematodes collected from palm weevil found in coconut plantations from the north of the Rio de Janeiro State. Light (LM) and scanning electron microscopy (SEM) analyses were carried on samples of infected R. palmarum and fragments and fresh juice of infected plants with B. cocophilus. Observations of R. palmarum fecal material made by LM and SEM showed three species cohabiting these samples, being also present in fresh juice and fragments of infected coconut tree: B. cocophilus, Teratorhabditis palmarum (Nematoda: Rhabditidae) and Diplogasteritus sp (Nematoda: Diplogasteridae). These findings confirm previous studies, which related that R. palmarum own a varied nematode fauna. Nematodes associated to B. cocophilus probably could be co-participates of the etiology of the Red Ring disease.
Abstract. Palm weevils have been reported as a pest and red ring nematode vectors for several palms of the Arecaceae family. Rhynchophorus palmarum L (Coleoptera: Curculionidae) is a pest for coconut crop and other palms. It is vector of Bursaphelenchus cocophilus (Cobb) Baujard (Nematoda) etiological agent of Red Ring disease and other nematodes. Current methods recommended use of enemies and parasites in integrated pest management of Rhynchophorinae. In addition, mass trap reduce environmental damage. The objectives of our study on coconut plantations were: (1) to determine the efficiency of low expensive kariomones traps and (2) low expensive kariomones and pheromones traps using adult males; and (3) to examine R. palmarum using light and scanning electron microscopy searching for ectoparasites which can be proposed in integrated pest management. Handmade kariomones mass traps were efficient to R. palmarum and other Curculionidae capture but kariomones plus adult male R. palmarum was maintained inside trap enhanced its attractiveness for this palm weevil and Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae). R. palmarum presented occasionally fungal infection. In contrast, mites infested more than 50% of palm weevils. Infestation level was always high. Surface morphology of the mites and its interaction with R. palmarum were briefly described. All stages of ectoparasites life cycle were observed onto weevil elytra compartments. In this way, morphological evidences suggest the hypothesis of these mites as used as biological control agent in R. palmarum integrated pest management.Keywords: Coconut palm; Curculionidae; Integrated Pest Management; Light and Electron Microscopy; Mites. Coleta Massal e Controle Biológico de Rhynchophorus palmarum L.:Uma hipótese baseada me evidências morfológicasResumo. Coleópteros têm sido descritos como pragas e vetores de nematódeos causadores de Anel Vermelho em diversas palmeiras da família Arecaceae. Rhynchophorus palmarum L (Coleoptera: Curculionidae) é uma praga que afeta a cocoicultura e outras palmeiras; e, vetor de Bursaphelenchus cocophilus (Cobb) Baujard (Nematoda), agente etiológico de Anel Vermelho e de outros nematódeos. Atualmente, recomendase o emprego de inimigos naturais e parasitas no manejo integrado de pragas; dentre elas, Rhynchophorinae. Armadilhas de coleta massal são recomendadas no manejo integrado de pragas. Nosso estudo relata, na cocoicultura, a eficiência de armadilhas artesanais de baixo custo e a utilização cariomônios (toletes de cana-de-açúcar) e cariômonios mais feromônios (toletes de cana-de-açúcar e machos adultos de R. palmarum) como atrativos nas armadilhas. Ácaros ectoparasitas foram identificados nestes coleópteros, por microscopia, que podem ser propostos como parte do manejo integrado desta praga. Armadilhas de coleta massal com cariômonios foram eficientes na captura de R. palmarum e outros Curculionidae. No entanto, armadilhas de coleta massal com cariômonios e feromônios aumentaram a atratividade, em relação às primeiras, par...
The present study exhibits original results of S. mansoni tegumental alterations due to contact with the immune system of non anti-helminthic treated mice. We compared, by SEM, the tegument of adult worms recovered from strains of mice genetically selected to extreme phenotypes of resistance (TR strain) and susceptibility (TS strain) to egg-albumin oral tolerance (OT). The parasites recovered from TR mice displayed no morphologic alteration, while specimens collected from TS mice presented tubercle swelling with blunted and shortened spines in lower density, increased sensory organelle numbers, fusion and tegumental ridge peeling. These tegument alterations were similar to those described for Artemether or Praziquantel treatment, supporting observations that the host immune system influences the development and function of the tegument of worms harbored in both anti-helminthic treated and non-treated mice. Our results are indicative that the development and function of the worm tegument depend on the immune regulatory capacity of each individual host.
Phytomonas wilt or Hartrot is a fatal disease of palm (Arecaceae) species including Cocos nucifera (coconut) and is caused by a phloematic trypanosomatid, a promastigote parasite that inhabits phloem sieve elements of disease palms. In the present work, we described the morphology of the interaction between a phloematic trypanosomatid (Phytomonas staheli) and C. nucifera. Two varieties and one ecotype of the adult coconut palm from northeast and southeast Brazil were analyzed, totaling 34,000 plants. Coconut palm losses due to Hartrot varied according to the variety or ecotype and geographic area. Occurrence of Hartrot was insignificant in Rio de Janeiro state (southeast), but in Bahia state (northeast) losses were substantial when appropriate cultural practices were not applied. Symptomatic and healthy palm tissues were analyzed by light and electron microscopy. Laboratory diagnoses revealed the twisted promastigote form of phloematic trypanosomatids in the extracts of shoot apex, leaves, stems and inflorescence in diseased plants, but not in the healthy ones. No parasites were found in the roots. Although the general anatomy of healthy and diseased palms was similar, callose deposition in the sieve plates was revealed by histochemistry and immunocytochemistry in the diseased tissue. Plugging by the P-protein and plastid alterations was also observed. Our observations strongly suggest that parasite traffic between sieve elements took place, although their cell bodies were larger than the sieve pores. Phloematic trypanosomatid proliferation in the sieve tube elements might interrupt the transport of phloem or/and consume plant nutrients. In addition, an association between the percentage of sieve elements colonized by pathogen in palm tissues and disease severity was established.
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