http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16786494&query_hl=1&itool=pubmed_docsum
Pest
Manag Sci. 2006 Aug;62(8):752-8.
Hazards
and uptake of chitin synthesis inhibitors in bumblebees
Bombus terrestris.
Mommaerts V, Sterk G, Smagghe G.
Department
of Biology, Faculty of Sciences, Free University of Brussels,
Brussels, Belgium.
This
research project examined the potential hazards of a major
class of insect growth regulators (IGRs) to survival,
reproduction and larval growth in bumblebees Bombus terrestris
L. Eight chitin synthesis inhibitors (CSIs) were tested:
buprofezin, cyromazine, diflubenzuron,
flucycloxuron, flufenoxuron, lufenuron, novaluron
and teflubenzuron.
These different IGRs, which are important in the
control of pest insects in greenhouses, were applied via
three different routes of exposure under laboratory conditions:
dermal contact, and orally via the drinking of sugar/water
and via pollen. The compounds were tested at their respective
maximum field recommended concentrations (MFRC) and also
in dose-response assays to calculate LC(50) values. In
general, none of the CSIs showed acute worker toxicity.
However, there was a dramatic reduction
in brood production, especially after oral treatment with
pollen and sugar/water. Conspicuously,
egg fertility
was reduced in all treatments with diflubenzuron and teflubenzuron.
In addition to egg mortality, the worker bumblebees removed
larvae from the treated nest, and in most cases these
individuals were dead first-second instars. Under a binocular
microscope, such larvae showed an abnormally formed cuticle
leading to mechanical weakness and death. In another series
of experiments using (14)C-diflubenzuron and (14)C-flufenoxuron,
cuticular penetration in workers was studied for a better
understanding of the differences in toxicity. With (14)C-diflubenzuron,
transovarial transport and accumulation in the deposited
eggs supported the strong reproductive effects. Overall,
the present results suggest that CSIs should be applied
with caution in combination with bumblebees. The
compatibility of each compound to be used in combination
with B. terrestris is discussed in relation to calculated
LC(50) values, routes of uptake and effects.
PMID:
16786494 [PubMed - indexed for MEDLINE]
NOTE
from FAN: 6 of the 8 pesticides
tested are fluorinated: diflubenzuron, flucycloxuron,
flufenoxuron, lufenuron, novaluron and teflubenzuron
|
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16112194&query_hl=1
Ecotoxicol Environ Saf. 2005 Aug
17; [Epub ahead of print]
Effects of insect growth regulators on
the nontarget soil arthropod Folsomia
candida (Collembola).
Campiche S, Becker-van Slooten K, Ridreau
C, Tarradellas J.
Ecole Polytechnique Federale de Lausanne, ENAC-ISTE, Laboratory
of Environmental Chemistry and Ecotoxicology, Station 2, CH-1015
Lausanne, Switzerland.
The aim of this study was to assess the effect of several insect
growth regulators (IGRs) on the nontarget soil arthropod Folsomia
candida (Collembola). The survival and reproduction rates of F.
candida were evaluated after 28 days of exposure to six IGRs (methoprene,
fenoxycarb, precocene II, tebufenozide,
hexaflumuron and teflubenzuron)
and to one herbicide (diuron) in artificial soil. The differences
in the sensitivity of F. candida to these different substances
are high. The chitin synthesis inhibitors
teflubenzuron and hexaflumuron were the most toxic compounds with
an EC50 of 0.05mg/kg (dry weight) for teflubenzuron and
an EC50 of 0.6mg/kg for hexaflumuron. Teflubenzuron
is toxic for F. candida at concentrations that are probably close
to environmental levels of this insecticide. Inhibition
of reproduction is strongly related to adult survival for the
juvenile hormone agonist methoprene and for the antijuvenile hormone
precocene II, with an EC50 of 173mg/kg and a LC50 of 178mg/kg
for methoprene and an EC50 of 15mg/kg and a LC50 of 26mg/kg for
precocene II. Fenoxycarb, another juvenile hormone analog, showed
a dose-response curve for mortality different from that of methoprene;
at concentrations such as 3052mg/kg no effect on adult survival
was observed. However, the EC50 value of 113mg/kg is of the same
order of magnitude as that obtained for methoprene. A test with
compressed soil contaminated with fenoxycarb was conducted to
observe parameters such as numbers of eggs laid and juveniles
hatched. No differences were observed between these two endpoints
for fenoxycarb. An EC50 of 109mg/kg was obtained for the ecdysone
agonist tebufenozide. The herbicide diuron showed a relatively
high toxicity for F. candida with an EC50 of 20mg/kg. Our
results show that some of the tested IGRs can have effects on
Collembola at environmentally relevant concentrations (toxicity/exposure
ratios <5 for teflubenzuron, hexaflumuron, and diuron).
PMID: 16112194 [PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16084001&query_hl=6
Environ Pollut. 2005 Aug 2; [Epub
ahead of print]
Effects of teflubenzuron on sediment processing
by members of the Capitella species-complex.
Mendez N.
Laboratorio de Invertebrados Bentonicos, Unidad Academica Mazatlan,
Instituto de Ciencias del Mar y Limnologia, UNAM, Apdo. Postal
811, Mazatlan, Sinaloa 82000, Mexico.
The cosmopolitan deposit-feeding polychaete Capitella is widely
used as an indicator of organic pollution and plays an important
role in waste recycling at aquaculture sites. Teflubenzuron
is currently employed by salmon farms as an in-feed compound to
control ectoparasite infestations. Its occurrence in sediments
could pose a hazard to local sediment infauna. A bioassay
to investigate the effects of exposing Capitella sp I and Capitella
sp B to sediment spiked with environmentally relevant concentrations
of teflubenzuron (8.4, 25 and 41.8 mug/g dry wt. sediment) is
described. No mortality was recorded for Capitella sp I, but increasing
teflubenzuron concentrations significantly reduced egestion rates.
Capitella sp B exhibited mortality, although egestion was not
affected. These results using Capitella
spp. indicated that teflubenzuron could affect the rate of sediment
processing by polychaetes close to fish farms treated with this
compound. Further studies are recommended to assess the
potential of contaminants in aquaculture wastes.
PMID: 16084001 [PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12152902
Dis Aquat Organ. 2002 Jun 21;50(1):29-33.
Field trials in Norway with SLICE (0.2%
emamectin benzoate) for the oral treatment of sea lice infestation
in farmed Atlantic salmon Salmo salar.
Ramstad A, Colquhoun DJ, Nordmo R, Sutherland
IH, Simmons R.
VESO Vikan AkvaVet, Namsos, Norway.
Four commercial salmon farms on the West coast of Norway were
recruited to a programme of field trials in which the efficacy
of SLICE (0.2% emamectin benzoate; Schering-Plough Animal Health)
was compared with a commercially available product, EKTOBANN
(teflubenzuron 2 g kg(-1); Skretting A/S) in treating natural
sea lice Lepeophtheirus salmonis infections in Atlantic salmon
Salmo salmar L. At each test site, 3 fish pens were treated with
each product. In total, nearly 1.2 million first-year-class fish
were included in the trial, of which approximately 561,000 received
emamectin benzoate at a dosage of 50 microg kg(-1) body wt d(-1),
while approximately 610,000 received teflubenzuron
at a dosage of 10 mg kg(-1) body wt d(-1). Medicated feed
was provided at 0.5% body wt d(-1) over 7 consecutive days. Feed
containing emamectin benzoate was generally well accepted by the
fish and no problems were encountered in feeding the medicated
diet at the desired dose. Lice numbers were counted 2 d before
and 1, 7, 14 and 21 d after commencement of treatment. While treatment
with both substances rapidly reduced lice numbers, pens treated
with emamectin benzoate were found to harbour significantly fewer
lice 14 and 21 d post-treatment. Twenty-one days following treatment
with emamectin benzoate the lice abundance was reduced on average
by 94%. Limited sampling outside the main study period indicated
that emamectin benzoate protects against sea-lice infestation
over longer periods.
PMID: 12152902 [PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11599720&dopt=Abstract
J Environ Sci Health
B. 2001 Sep;36(5):559-67.
Transformation
of the insecticide teflubenzuron by microorganisms.
Finkelstein
ZI, Baskunov BP, Rietjens IM, Boersma
MG, Vervoort J, Golovleva LA. G.K.
Skryabin Institute
of Biochemistry and Physiology of Microorganisms, RAS, Pushchino,
Moscow.
Transformation of teflubenzuron,
the active component in the insecticide commercialized as Nomolt,
by soil microorganisms was studied. It was shown that microorganisms,
belonging to Bacillus, Alcaligenes, Pseudomonas and Acinetobacter
genera are capable to perform the hydrolytic cleavage of the phenylurea
bridge of teflubenzuron in different positions, especially active
was Bacillus brevis 625. The structure of the intermediates formed
was established using TLC, HPLC, mass-spectrometry and 19F NMR
techniques. It was shown that for a dose range of 53-132 microM
and upon 12 days of fermentation about 30% of the teflubenzuron
was modified. About 10-15% was transformed into 2,6-difluorobenzamide,
3-5% into 2,6-difluorobenzoic acid,
10-12% into 2,4-difluoro-3,5-dichloro-aniline.
The late compound gave rise to formation of a condensed compound,
identified as 1,2-bis(2,4-difluoro-3,5-dichlorophenyl)urea
with molecular mass of 420. The results obtained indicate degradation
of teflubenzuron by soil microorganisms to be a process to be
mediated by microbial consortia, and starting with hydrolysis
of the phenylurea bridge by several bacterial species. Subsequent
further degradation of the aromatic degradation products has to
be mediated by other strains known to be capable of degradation
of halogenated aromatics.
PMID: 11599720
[PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10552854&dopt=Abstract
J Agric Food Chem.
1999 Nov;47(11):4583-6.
Evaluation
of teflubenzuron residue levels in grapes exposed to field treatments
and in the must
and wine produced from them.
Tsiropoulos
NG, Aplada-Sarlis PG, Miliadis GE.
Benaki Phytopathological
Institute, 7 Ekalis Street, Kifissia 14561, Greece. ntsirop@uth.gr
Dissipation of benzoylurea
insecticide teflubenzuron in grapes exposed to field treatments
was evaluated. Vines of a white grape vineyard located in central
Greece were sprayed twice, at a 28-day interval, with a commercial
formulation of the insecticide at 12 g of active ingredient/100
L. Residues were determined by HPLC diode array detection, after
ethyl acetate extraction and cleanup on silica phase cartridges,
with a detection limit of 0.005 mg/kg. Under
field conditions teflubenzuron residues in grapes were found to
be very stable with no significant reduction for the whole experimental
period of 49 days. However, residues were slightly lower
than the maximum residue limits set by individual countries. The
fate of teflubenzuron during the vinification process was also
studied. Residues were found to be transferred completely into
the must but, due to their high affinity for the suspended matter,
were removed by approximately 98%; thus, very low concentrations
were detected in the produced wine. Among various clarifying agents
studied, charcoal was the only one found
to be effective for removing teflubenzuron residues from wine.
PMID: 10552854
[PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10552588&dopt=Abstract
J Agric Food Chem.
1999 Jul;47(7):2926-9.
Dissipation
of teflubenzuron and triflumuron residues in field-sprayed and
cold-stored pears.
Aplada-Sarlis
PG, Miliadis GE, Tsiropoulos NG.
Department of Theoretical
and Applied Sciences, University of Thessaly, Pedion Areos, Volos
38334, Greece.
Dissipation of residues
of benzoylurea insecticides teflubenzuron
(TFB) and triflumuron (TFM) under field conditions was
evaluated on a pear orchard in Greece. Residues were determined
by UV-HPLC analysis, with a detection limit of 0.030 mg/kg for
both pesticides. TFB residues in pears were found to persist for
2 weeks and decline thereafter with 48% of the initial deposit
remaining 42 days after the last application. TFM residues were
found to decline following first-order kinetics and with a half-life
of 39(+/-7) days. Residues of both pesticides found in pears collected
at harvest maturity were lower than the maximum residue limits
(MRLs) set by individual countries. Dissipation of TFB and TFM
in cold-stored pears was also evaluated. TFB
residues were very persistent for the whole storage period,
whereas TFM residues did not dissipate for 6 weeks and then showed
a constant decline; 7% of the initial concentration remained at
the end of the storage period of 29 weeks.
PMID: 10552588
[PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9293617&dopt=Abstract
Xenobiotica. 1997
Aug;27(8):801-17.
Metabolism
of the insecticide
teflubenzuron in rats.
Koerts
J, Soffers AE, De Kraker JW, Cnubben NH, Rietjens IM.
Department of Biochemistry,
Agricultural University Wageningen, The Netherlands.
1. The metabolic fate
of the insecticide teflubenzuron, orally dosed to the male Wistar
rat, was investigated. Particular attention was paid to the metabolic
fate of the benzoyl and aniline moiety after hydrolysis of the
urea bridge.
2. The 0-48-h urinary and faecal metabolic patterns and recoveries
showed that for a dose range of 4-53 mumol (1.5-20 mg) teflubenzuron,
90% of the dose was excreted in the faeces mainly in unmodified
form, approximately 4.6% was absorbed from the lumen and excreted
in the urine, and 5.4% was retained in the body. Metabolites excreted
in the urine could be identified as benzoate and aniline derivatives
originating from the two aromatic rings of teflubenzuron liberated
from the parent molecule by hydrolysis of the urea bridge.
3. The amount of urinary benzoate-type metabolites was about eight
times the amount of aniline-type metabolites, indicating significant
differences in efficiency of urinary excretion of the benzoate
moiety as compared with the aniline ring.
4. To investigate further the possible reason underlying this
difference in urinary excretion efficiency between the two aromatic
derivatives formed from teflubenzuron, dose-recovery studies of
these aniline- and benzoate-type metabolites were performed. These
studies confirmed the discrepancy observed between the urinary
recovery of the benzoyl and the aniline moiety of teflubenzuron.
5. Additional results of the present study indicate that the above
discrepancy can be explained by the fact that the benzoate derivative
is excreted mainly in its unmetabolized form, whereas the aniline
derivative needs additional phase I and II modifications before
it can be excreted from the body, the former being a relatively
slow reaction. Furthermore, conversion of the halogenated aniline
derivative in phase I metabolism might result in a reactive benzoquinone-type
or N-oxidized primary metabolite, which can be retained in the
body due to reaction with cellular macromolecules.
PMID: 9293617
[PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9037873&dopt=Abstract
Eisei Shikenjo Hokoku.
1996;(114):95-8.
[First
drafts of the Environmental Health Criteria (EHC) circulated for
comments by IPCS in 1995-1996]
[Article
in Japanese]
Ohtake
C.
Summaries
of first draft of Environmental Health Criteria (EHC), which were
circulated for comments by IPCS in the period of 1995-1996, are
presented. EHC drafts on 9 compounds were received in this period.
PMID: 9037873
[PubMed - indexed for MEDLINE]
From Toxline at Toxnet
Pesticide residues in food - 1993. Toxicology evaluations Vol:Part
II (1995) pp 171-88
Teflubenzuron
FAO and WHO working groups
Levels that cause no toxic effect.
Mouse: 100 ppm, equal to 11.9 mg/kg bw per day (13-week study
of toxicity)
Rat: 100 ppm, equal to 4.8 mg/kg
bw per day (120-week study of toxicity and carcinogenicity) 500
ppm, equal to 40 mg/kg bw per day (two-generation study of reproductive
toxicity) 1000 mg/kg bw per day (study of teratogenicity, maternal
and fetal toxicity)
Rabbit: 1000 mg/kg bw per day (fetal
toxicity in a study of teratogenicity) 250 mg/kg bw per day (maternal
toxicity in a study of teratogenicity)
Dog: 100 ppm, equal to 3.2 mg/kg
per day (one-year study of toxicity) Lowest-observed-adverse-effect
level.
Mouse: 15 ppm, equal to 2.1 mg/kg
bw per day (18-month study of carcinogenicity)
Humans: Estimate of acceptable daily
intake for humans. 0-0.01 mg/kg bw.
Studies that would provide information useful for continued evaluation
of the compound. Further observations in humans.
From Toxline at Toxnet
Journal of Applied Toxicology, Vol. 13, No. 1, pages 67-68, 7
references, 1993
Comparative Study on the Effects of Five
Benzoylphenylurea Insecticides on Haematological Parameters in
Rats
Tasheva M, Hristeva V
The effects of five benzoylphenylurea insecticides, diflubenzuron
(35367-38-5), flufenoxuron (101463-69-8), hexaflumuron (86479-06-3),
teflubenzuron (83121-18-0), and triflumuron
(64628-44-0) were comparatively evaluated on hematological parameters
in rats. Sixty adult Wistar-rats were divided into five dose groups
and a control group. Daily doses of 100mg/kg of each tested insecticide
were administered by gavage for 28 days, after which rats were
sacrificed and blood was taken for examination. Parameters measured
were red blood cell count, hemoglobin (Hb), hematocrit, mean corpuscular
volume, mean corpuscular Hb concentration, methemoglobin (metHb),
and reticulocyte counts. Results showed that treatment with insecticides
at the dose given did not produce any overt signs of toxicity.
However, with regard to hematological parameters, both diflubenzuron
and triflumuron induced elevated metHb levels. The no observed
effect level for metHb was 45mg/kg. The
reticulocyte level was increased in all treated groups, even at
dose levels of 50mg/kg. The authors conclude that the metHb level
increase and reticulocyte increase are the most sensitive parameters,
but that one might be independent of the other.
Note: All the pesticides cited are fluorinated
Return
to Teflubenzuron Index Page