Background The tobacco cutworm, Spodoptera litura [Fab.] (Lepidoptera: Noctuidae), is a devastating insect pest of several crops. Entomopathogenic nematodes (EPNs) of the families Heterorhabditidae and Steinernematidae are used as an alternative control measure in lieu of the hazardous synthetic chemical applications. Results A survey of naturally occurring EPNs was conducted across the province of Cotabato, Philippines, covering a total of 5 municipalities with 25 villages. Galleria-baiting technique was employed to recover nematodes from peanut and grassland soils. Out of 50 soil samples collected, only 5 samples harbored nematodes, indicating a recovery of 10%. Preliminary morphological data identified only one EPN under the genera Heterorhabditis (1 isolate), whereas 4 were facultative necromenic nematodes from the genera Metarhabditis (2 isolates) and Oscheius (2 isolates). Analysis of D2D3 segments of the 28S rDNA confirmed high sequence similarity to Heterorhabditis indica, Metarhabditis rainai, Oscheius insectivora, and Oscheius sp. This is the first record of H. indica and M. rainai in the entire region, whereas the first record for Oscheius spp. in the Philippines. Furthermore, the biocontrol potential of the local H. indica infective juvenile (IJ) populations (PIGCD1) isolated from peanut was assessed against the tobacco cutworm, S. litura, under laboratory conditions. The mean percentage mortality caused by H. indica on S. litura at 7 different concentrations ranged from 0-100% at 24 h post inoculation. The lethal concentration (LC50) required to kill 50% of the S. litura larvae population with H. indica was 7.13±1 (IJs/larva). Conclusions The use of Galleria-baiting method is a convenient approach to detect EPNs including other facultative necromenic nematodes from the soils. Obtained data indicated that the local H. indica isolate can be a promising alternative measure to suppress the economically important insect pest, S. litura, and this may provide significant outlook to establish the biocontrol program in the country.
Pigs play a key role in inter-species transmission of influenza virus, because they have receptors to both avian and human influenza viral strains. A study was conducted in three different districts namely Bhaktapur, Kavre and Banke with face to face type of questionnaire survey and serum sample collection. Indirect Enzyme Linked Immunoassay was utilized for the collected 231 samples for serologic evidence of influenza A. Of the total 231 samples tested, 11 were positive for Influenza virus A with an overall sero-prevalence of (4.76%; Cl95%: 2.68-8.324) Kavre district had highest (5.88%; Cl95%: 2.539-13.04) sero-prevalence, followed by Bhaktapur (5.13%; Cl95%: 2.012-12.46) and Banke (2.94%; Cl95%; 0.8104-10.1) with no significant difference (p=0.685). Rearing swine along with poultry was the most significant risk factor (p=0.03); all positive cases were from the farms that adopted integrated farming system with little to no bio-security measures, especially poultry and swine. Present finding depicts that Influenza A is prevalent in pig farms of Kavre, Banke and Bhaktapur. Further research is needed to sub-type the influenza virus and also determine the effect of commercial poultry and migratory birds on the outbreak of influenza A in swine. Int. J. Appl. Sci. Biotechnol. Vol 6(2): 122-126
A study on reproductive disorders among yaks in Mustang and Solukhumbu districts and seroprevalence of brucellosis among yaks in Mustang and Myagdi districts was conducted. Eleven farmers having 383 female and 72 male yaks in Mustang and 129 female and 27 male yaks in Solukhumbu districts were taken by purposive random sampling for the study on reproductive disorders. Likewise Sixty-seven serum samples were also collected from adult female yaks having history of abortion and retained placenta, and from male yaks used for breeding purpose from Mustang and Myagdi districts. An average of 12.63% of female yaks aborted, 7.26% had had retention of placenta and 6.6% repeat breeders in Mustang district. Similarly, 6.3% had abortion, 2.09% retained placenta and 6.5% repeat breeders in Solukhumbu district. However, all the 67 serum samples examined were found negative to the Brucella abortus antibody on ELISA test suggesting that the yak population was free from brucellosis in these areas. Thus abortion and retention of placenta in Yak in Mustang district may not be due to brucellosis. A detail study should be done to find the specific cause of abortion and repeat breeding to recommend preventive and control measures.
Bacterial resistance to antibiotics occurs even without the use of antibiotics. Antibiotic use exerts a selective pressure to the bacterial flora that help in the emergence and development of antibiotic resistance. Antibiotics are used worldwide both in veterinary and human medicine. The wide spread use of antibiotics in human and animal has raised the concern about the development of resistant and multi resistant bacteria that possess a potential danger to animals and men, as resistance may cause treatment failure. Resistance may be natural or acquired. Acquired resistance is due to transfer of extrachromosomal genetic material (R-plasmids) and is very important. The R-plasmids are spread to other bacterial cells by transformation, transduction, conjugation and transposition. Transmitted antibiotic resistance in disease causing bacteria may cause zoonotic infections and resistant non-infectious bacteria may serve as a reservoir of R- plasmids for the pathogenic organism(s). This paper highlights the mechanism of development of resistance in bacteria and means to minimize it.Key words: Antibiotic resistance; Bacteria; Extrachromosomal material; Resistance; R-plasmidsDOI: http://dx.doi.org/10.3126/narj.v4i0.4873Nepal Agriculture Research Journal Vol. 4&5, 2001/2002Page: 66-70Uploaded date: 9 June, 2011
Background Entomopathogenic nematodes of the genera Heterorhabditis and Steinernema are widely used as biocontrol agents against diverse insect pests. Their association with symbiont bacteria is found to be the primary cause of insect mortality. The present study reported a comprehensive characterization of a local Philippine EPN isolate using congruent morpho-taxometrical and molecular data and the associated bacterium in the infective dauer juveniles. Results Using an insect-baiting technique, a nematode isolate labeled F2H was recovered from the sandy soils in the coastal area of southern Philippines. Based on morphology and morpho-taxometrics, the F2H isolate collected from Iligan City was identified as Heterorhabditis indica. Analysis of the ITS region of rDNA revealed the highest sequence match to H. indica. The sequences of the bacterial 16S rDNA gene showed that the symbiont of H. indica presented 100% similitude with the sequences of Ochrobactrum anthropi. Further, pairwise alignment and phylogenetic analysis demonstrated that O. anthropi, O. lupini and O. cytisi shared 100% similarity and form a monophyletic clade. These strains have not presented any differences in the phylogenetic and 16S rDNA data, and O. lupini and O. cytisi should be considered a later heterotypic synonym of O. anthropi. Conclusions The description of H. indica-O. anthropi association was the first report in the Philippines. This provides additional account and collection of naturally isolated EPN-bacteria, contributing to limited knowledge on its diversity in the Philippines, which can be utilized in the biocontrol of pests after further comprehensive assessments.
Entomopathogenic nematodes (EPNs) are commonly used biocontrol agents of insect pests, with a wide range of commercially available isolates targeting specific pests. New isolates are, however, required to improve pest control across a wider range of environmental conditions for target pests, including emerging threats. We assessed the effect of temperature on survival and virulence of 17 Australian isolates of five EPN species (Heterorhabditis bacteriophora, Heterorhabditis indica, Heterorhabditis marelatus, Heterorhabditis zealandica and Steinernema feltiae) against larvae and pupae of the Queensland fruit fly, Bactrocera tryoni. All isolates still infected and killed larvae after infective juveniles (IJ) had been kept without insect hosts at 15 °C, 25 °C or 30 °C for two weeks, indicating their potential to remain viable under field conditions. However, the mean LD50 value ranged from 35 to 150 and was generally lower at 15 °C than at 25 °C and 30 °C. Similarly, after IJs had been kept at 25 °C for 1–3 weeks without insect hosts, all isolates infected B. tryoni larvae, with mean LD50 values ranging from 25 to 144. Interestingly, 15 isolates infected and killed B. tryoni pupae after one week, with a mean LD50 value between 130 and 209, but only two isolates after two weeks, with a mean LD50 value between 229 to 209. No pupal mortality was seen after three weeks. In absence of hosts, EPNs survived longer at 15 °C and 25 °C than at 30 °C. Complete EPN mortality occurred after nine weeks at 30 °C, and after 18 weeks at 15 °C and 25 °C, except for some survival in one S. feltiae isolate (Sf.ECCS). Overall, six isolates of H. indica (Hi.HRN2, Hi.LMI2, Hi.QF6), H. bacteriophora (Hb.HIE), H. zealandica (Hz.NAR1) and S. feltiae (Sf.ECCS) performed best and need further testing as potential biocontrol agents against B. tryoni under semi-field and field conditions.
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