RESUMO
Cultivation of species of the genus Eucalyptus is important for the Brazilian economy, with 6.97 million hectares planted. Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae), detected in Brazil in 2003, has dispersed and now damages Eucalyptus crops in all regions of this country. The location and identification of entomopathogenic fungi isolates may increase the options for integrated pest management. The objective of this research was to evaluate the pathogenicity of Cordyceps cateniannulata and Cordyceps javanica isolates to G. brimblecombei. Ten nymphs of G. brimblecombei, with or without lerps, were placed per Eucalyptus leaf cut with one of its edges on hydroretentive gel inside Petri dishes. The fungi isolates were suspended in a solution of Tween 80 (0.1%) at the concentration of 1.0 x 108 conidia mL-1 and sprayed on the G. brimblecombei nymphs. The mortality of this insect was evaluated daily for seven days, and the dead individuals were transferred to humid chambers. The conidia viability of the isolates was greater than 93%. The mortality of G. brimblecombei nymphs, seven days after the application of the fungi, was 100%. This is the first report of the pathogenicity of C. cateniannulata and C. javanica isolates, occurring naturally in the field, to G. brimblecombei.
Assuntos
Cordyceps , Eucalyptus , Hemípteros , Animais , Esporos Fúngicos , VirulênciaRESUMO
Entomopathogenic nematodes (EPNs) can control pests due to their mutual association with bacteria. The use of these biological control agents is increasing worldwide due to advances in research about its control efficiency, range of action and mass production. The identification of EPNs adapted to specific environmental and climatic conditions is important for sustainable pest suppression in integrated management (IPM) programs. The objective is to report, for the first time, the occurrence of the Steinernema diaprepesi in Brazil. Steel mesh traps with Galleria mellonella Linnaeus (Lepidoptera: Pyralidae) larvae were buried in red latosol cultivated with Eucalyptus. Infective juveniles (IJs) were isolated from dead larvae and multiplied in healthy ones of this host to confirm its pathogenicity and to start a laboratory population from the strain found in the field. The DNA of the IJs was extracted and amplified using PCR technique with the universal primers D2A and D3B. The detection of S. diaprepesi is the first report of this nematode in Brazil, increasing the knowledge about its distribution in the world and the diversity of EPNs that must be considered as agents of biological pest control in the country.
Assuntos
Mariposas , Rabditídios , Animais , Brasil , Larva , Controle Biológico de VetoresRESUMO
The sugarcane borer, Diatraea saccharalis is one of the hosts more used for parasitoid pupal multiplication in Brazil. The parasitoids pupal of Trichospilus diatraeae and Palmistichus elaeisis are generalist natural enemies with potential to suppress populations of diverse families of lepidopteran pests. The success in the utilization of these natural enemies in the field is directly related to the capacity of search of the host, this capacity might be affected by the presence of the pathogens. In this context, the aim of this essay was to detect the presence of intracellular parasites of Phylum Microsporidia. These pathogens may cause morphological and behavioral alterations. The presence of infection was verified by microscopy and was confirmed by amplification of region small subunit (SSU) of ribosomal RNA using universal primers for microsporidia of Nosema sp. The purified PCR products were submitted to sequencing, and the sequences that had been obtained were edited and aligned with the sequences in a Genbank database. In this way, it was possible to verify the presence of intracellular parasites in T. diatraeae, P. elaeisis and D. saccharalis pertaining to Clade Nosema/Vairimorpha. However, this is the first one report about detection of the microsporidia in the parasitoids T. diatraeae and P. elaeisis.
Assuntos
Interações Hospedeiro-Parasita/fisiologia , Mariposas/parasitologia , Nosema/fisiologia , Controle Biológico de Vetores/métodos , Pupa/parasitologia , AnimaisRESUMO
BACKGROUND: Escherichia coli is believed to participate in the etiology of Crohn's disease (CD) and possibly of ulcerative colitis (UC), due at least in part to the observed rise in the number of these bacteria in the gut microbiota of CD and UC patients. Nevertheless, it is not fully understood whether this quantitative variation occurs equally throughout the mucosal and luminal spaces of the gut. To assess this question, stools and mucosa biopsies from distinct intestinal sites were cultured aiming at determining their E. coli concentration. The cultures were additionally screened for the presence of some virulence genes of pathogenic E. coli. RESULTS: Analyses of clinical materials from 14 controls (38 biopsies and 14 stools samples), 11 CD (25 biopsies and 11 stools samples) and 7 UC patients (18 biopsies and 7 stools samples) indicated no significant variation in the number of E. coli present in stools, but a rise of at least one log10 CFU/mg in biopsies from the ileum of CD patients and the sigmoid and rectum of CD and UC patients. The cultures were screened for the presence of E. coli attaching and effacing (eae), invasion plasmid antigen H (ipaH), aggregative adherence transcriptional activator (aggR), Shiga cytotoxins (stx), and heat labile enterotoxin (elt) and the following serine proteases autotransporters of Enterobacteriaceae (SPATE) genes: plasmid encoded toxin (pet), secreted autotransporter toxin (sat), Shigella extracellular protein (sepA), protein involved in intestinal colonization (pic) and Shigella IgA-like protease homolog (sigA). Six of the 10 genes screened were detected in the total of samples investigated: aggR, eae, pet, sat, sepA and sigA. No difference in the prevalence of any of these markers was observed in cultures from different clinical materials or groups of patients. METHODS: Bacterial quantitation was carried out following cultures of diluted samples suspensions in MacConkey agar, Wilkins Chalgren agar for anaerobes, E. coli/coliform chromocult agar, and blood agar. Screening for E. coli virulence genes was performed by multiplex PCR of DNA purified from total MacConkey undiluted broth cultures. CONCLUSION: In CD and UC patients only the mucosa associated population of E. coli is augmented and the proliferation is prominent in the ileum of CD and rectum and sigmoid of both UC and CD patients which are sites where the lesions usually are observed. The augmented E. coli population in these sites presented a low number of the virulence markers, possibly meaning that they are not relevant for the disease process.