Calicide - a critique of its proposed licence by SEPA as a sea lice control agent in salmonid aquaculture

 The 1999 ASP disaster has awakened some shellfish farmers and scientists to the realisation that all the regulators want to do is to comply with 'policy', sense or nonsense alike!
Allan

Calicide - a critique of its proposed licence by SEPA as a sea lice control agent in salmonid aquaculture
Author confidential TPTI.

1. Introduction
Calicide is a trade name of teflubenzuron, a benzoylphenylurea (BPU) insecticide. Other (BPU) insecticides are diflubenzuron, triflumuron, hexaflumuron, lufenuron, chlorfluazuron, flufenoxuron and flucycloxuron (Hiemstra et al., 1999). Teflubenzuron has been used as an insect growth inhibitor and has been principally studied in its role as an insecticide.
Apart from sea lice, there have been few studies regarding toxicity to marine organisms, or the ecological effects of its long-term use in the marine environment even though the manufacturers state that teflubenzuron
is:
1. Dangerous for the environment;
2. Very toxic to aquatic organisms;
3. May cause adverse long term effects in the environment (Trouw Aquaculture, 1993).

2. Species susceptible to teflubenzuron
The Scottish Environmental Protection Agency (SEPA) state that "teflubenzuron is a chitinase inhibitor and exerts toxicity by inhibiting the formation of chitin which is the predominant component of the exoskeleton of insects and crustacea. It therefore exerts an effect at a moulting stage in the life cycle of exposed organisms" (SEPA, 1998). This statement is highly selective regarding the effects of teflubenzuron.

Teflubenzuron has been demonstrated to be a non-specific chitin synthesis inhibitor, for example, it also prevents the formation in the chitinous case of insect eggs (Furlong et al, 1994). The mechanism by which teflubenzuron inhibits chitin synthesis has been shown to be blockage of N-acyetyl-D-glucosamine incorporation into chitin (Mikolajczyk et al.,1994). The mechanism would indicate that teflubenzuron inhibits all chitin synthesis. To state that teflubenzuron "exerts an effect at a moulting
stage in the life cycle of exposed organisms" indicates that SEPA are ignorant of the range of species that will be directly affected by teflubenzuron.

The Insecta is a class of the phylum Arthropoda. The Arthropods are an immense assemblage of animals. At least three quarters of a million species have been described: this is more than three times the number of all other animal species combined! The distinguishing feature of all arthropods is the chitinous exoskeleton (Barnes, 1987), thus teflubenzuron is lethal to them all.

The production of chitin is not unique to the Arthropoda. The Arthropods are thought to have evolved from the phylum Annelida ("worms") which contain over 8,700 described species. Unsurprisingly then, the Annelida also produce chitin: the setae ("hairs") of the body segments, each grown from a single cell. The setae have, through evolution, developed into a
range of structures with varying functions from locomotion (e.g. ragworms) to protection (e.g. fireworms) (Barnes, op. cit.). Teflubenzuron then is probably lethal to them all.

The Mollusca includes the bivalves, squids, octopods and snails. In abundance of species the molluscs constitute the largest invertebrate phylum apart from the Arthropods with over 50,000 described species. Whilst the mollusca have radiated into many forms, the generalised mouthparts consist of a chitin-lined buccal ("cheek") cavity which contains the uniquely molluscan feeding organ, the radula. The radula apparatus consists of an elongated, cartilagenous base, the odontophore. Over the odontophore and around its anterior is stretched a membranous belt, the radula proper, which bears a number of rows of chitinous teeth. The anterior teeth wear out and are replaced by continuously secreted teeth at the rate of one to
five rows per day. In addition, the stomachs of molluscs are lined with chitin which prevents the stomach from damage by sharp surfaces (Barnes, op. cit.). Whilst the Molluscan class Bivalvia do not have radulae, the chitinous stomach lining has been retained in the form of the gastric shield (Beninger and Le Pennec in Shumway, 1991). Teflubenzuron is probably lethal to all Mollusca much more rapidly than to the Arthropoda which are affected only during ecdysis (moulting).

The phyla Mollusca and Arthropoda are thought to have evolved from the Annelida (Barnes, op. cit.). Thus the chitin sysnthesis mechanism is probably very similar if not the same in all three phyla and will be equally susceptible to teflubenzuron. However there have been no studies on LC50 values (the concentration of teflubenzuron required to kill 50% of a sample of animals) for any marine species of these three major phyla, either as adults or during their larval stages in the zooplankton. More
especially, there have been no studies on the effects on the adults or larvae of commercially important species of Crustaceans (crabs, lobsters, prawns etc.) or molluscs (scallops, mussels, cockles, whelks, winkles etc.), many of which have extended planktonic larval stages. Elimination of these any of these species even in a limited area will allow significant changes to benthic communities, however, there have been no trials of long term ecological effects of teflubenzuron use.

SEPA (op. cit.) also state that "teflubenzuron is relatively non-toxic to most marine species (e.g. fish, algae, shellfish)" . The work has not been done. The prima facie evidence is that teflubenzuron will be highly toxic to shellfish. SEPA are therefore grossly ignorant of the range of species that will be directly affected by teflubenzuron.The lethal effects are: by prevention of growth in the Arthropoda; prevention of movement in the Annelida and death by starvation and internal damage in the Mollusca. There have been no studies of long term ecological effects of the use of teflubenzuron. They could be immense but have not been considered in its proposed use as Calicide.

Mr. Brian Bellwood of SEPA, in a letter to David Oakes dated 14 April 2000, state that "the controlled use of the chemical [teflubenzuron] will have no significant effect on flora and fauna therefore the interests of shellfish growers should not be prejudiced by the use of this product". This is in direct contradiction to the SEPA (1999) statement that "Some of the
residues of in-feed treatments [including teflubenzuron] are very long-lived and may accumulate in sediments close to the cages or further afield. These residues may then endanger non-target species or re-enter the food chain in, for example shellfish".

Q. 2.1. On what studies, and with regard to which species, do SEPA base their Total Allowable Quantity discharge values?
Q. 2.2. On what basis does SEPA regard teflubenzuron "relatively non-toxic" to other marine life including shellfish?
Q. 2.3. On what basis does Mr. Brian Bellwood of SEPA justify his statement that "the controlled use of the chemical [teflubenzuron] will have no significant effect on flora and fauna therefore the interests of shellfish growers should not be prejudiced by the use of this product".
Q. 2.4. What was the cause of the massive invertebrate kill during a Calicide trial in Lochbay, Skye in 1996?

3. Biodegradability and sediments
Teflubenzuron is not readily biodegradable (Trouw Aquaculture, 1993) and is partially soluble in water (Trouw Aquaculture, 1993; SEPA, 1998). For example:
A. Dissipation of teflubenzuron was studied in grapes, sprayed twice, at a 28-day interval, with a commercial formulation of the insecticide at 12 g of active ingredient/100 L. 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. 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 similar to 98%; thus, very low concentrations were detected in the produced wine (Tsiropoulos et al.,1999). Dissipation of teflubenzuron in cold-stored pears was also evaluated. Residues were very persistent for the whole storage period of 29 weeks (ApladaSarlis et al., 1999).

Teflubenzuron is toxic to over three quarters of all known species in the animal kingdom. These include the Annelida and other species that are involved in bioturbation of sediments. The prima facie evidence suggests that after the use of teflubenzuron the sediments will be azoic, bioturbation will be greatly reduced, if not totally inhibited, with a consequent spread of the benthic impact zone. Teflubenzuron will not be biodegraded and will continually dissolve into the water column with as yet
unknown lethal and semi-lethal effects on zooplankton. Areas under salmon cages that have been left fallow very quickly return to a polluted status when aquaculture operations recommence (SEPA, 1999).

Q. 3.1. On what basis do SEPA suggest that a fallow period of 2 months in every 24 will aid seabed recovery?
Q. 3.2. What is the basis of the maximum allowable re-treatment quantity formulation?
Q. 3.3. As teflubenzuron is not readily biodegradable, why has Professor
D. Mackay stated, when discussing chemical theraputants used in sea lice control "contemporary market medicines ....  are carefully designed  ....and then permit rapid breakdown " (SEPA 1999) ?

4. Side effects
Teflubenzuron has been shown to affect predators and parasites of target organisms. For example:
A. In a study of 10 insecticides, 5 fungicides and 5 herbicides on 24 different species of beneficial insects (predators), the benzoylurea's teflubenzuron (Nomolt) and flufenoxuron (Cascade) affected predators such as anthocorids, earwigs, coccinellids and lacewings (Sterk et al., 1999).
B. Trichogramma pretiosum Riley is an important natural enemy used for the biological control of Tuta absoluta in tomato fields in several countries
in South America. The side-effects of insecticides on T. pretiosum was tested by dipping parasitized host eggs (Ephestia kuchniella Zeller) at three different development stages (egg-larvae, pre-pupae and pupae) in pesticide solution at recommended concentrations. The insecticides varied in their toxicity and significantly affected the development time of the
immature stages, emergence, parasitism and longevity of the adult parasitoid. Tebufenozide, teflubenzuron and abamectin had sub-lethal effects. They reduced the time of development, especially when applied during the pupae stage. The capacity of parasitism of emerged females decreased and was affected by the stage of development treated (Consoli etal., 1998).
C. Several pesticides were tested in the laboratory for their side-effects upon the mirid bug Dicyphus tamaninii, a polyphagous predator used for IPM programmes in some vegetable crops. Residual toxicity to 3rd -4th instar nymphs on tomato leaflets was checked 24, 48 hours and seven days after treatment. The acaricides bromopropylate, dicofol+tetradifon and fenpyroximate were harmless to the nymphs. The insect growth regulators azadirachtin, buprofezin, lufenuron and pyriproxyfen were also harmless to nymphs and teflubenzuron was harmful seven days after treatment. Among the conventional insecticides tested, only pirimicarb and tau-fluvalinate were harmless to D. tamaninii nymphs (Castane et al., 1996).

5. Metabolism in mammals and fish
Teflubenzuron is only partially metabolised in vertebrates. for example A. Koerts et al. (1997) investigated the metabolic fate of the insecticide teflubenzuron, orally dosed to the male Wistar rat. Particular attention was paid to the metabolic fate of the benzoyl and aniline moiety after hydrolysis of the urea bridge.
The 0-48-h urinary and faecal metabolic patterns and recoveries showed that for a dose range of 4 - 53 µ mol (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.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.
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.
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 un-metabolized 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.
B. In salmon, 90% of the material will be released from the fish via faeces in the period immediately following treatment (SEPA, 1998).

Q. 5.1. Presumably 5% of teflubenzuron is partially metabolised by salmonids ( as it is in rats) and discharged into the water column, although this was not mentioned by SEPA. What work, if any, has been undertaken on the metabolism of teflubenzuron in salmonids?
Q. 5.2. What work, if any, has been undertaken on the lethal and sub-lethal effects of the water soluble metabolites of teflubenzuron on any other marine species?

6. Resistance
A range of target organisms have been shown to develop resistance to teflubenzuron. In addition, cross-resistance is developed with other BPUs.
For example:
A. Failure in the control of the codling moth, Cydia pomonella L., with diflubenzuron was observed for three years in several locations of southern France. A laboratory procedure was set up to screen field populations for resistance to insecticides which regulate or inhibit insect development. These tests revealed a 370-fold resistance to diflubenzuron in one population of C. pomonella. Cross-resistance was observed with the two other benzoylureas registered in France against this species: teflubenzuron (seven-fold resistance) and triflumuron (102-fold resistance). The two populations observed also presented cross-resistance (26-fold) with the ecdysone analogue tebufenozide (benzoylhydrazine), to which they had not previously been exposed. This is the first record of naturally occurring resistance to this new compound. Ovicidal tests on F3 progeny also
indicated possible cross-resistance with the juvenile hormone analogue, fenoxycarb, for one strain. The resistance to these different insecticides appears to be co-dominant.
B. French populations of the codling moth Cydia pomonella (L.)
(Lepidoptera, Tortricidae) have developed resistance to different classes of insecticides including diflubenzuron. Ovicidal tests performed on two susceptible strains and one strain selected for its resistance to diflubenzuron revealed the same order of magnitude in resistance ratios to this compound (30-fold) and two other benzoylureas teflubenzuron and flufenoxuron (22-and 11-fold, respectively). Field rates of these three compounds induced a 45-55% decrease in hatching in the resistant strain,
compared to over 90% in the susceptible insects. Despite a 52-fold ovicidal resistance ratio to the juvenile hormone analogue fenoxycarb, this compound induced a 85% decrease in hatching in the resistant strain. Conversely the newly hatched larvae of the resistant strain exhibited a 45 000-, 33- and 2.1- fold resistance ratio to diflubenzuron, teflubenzuron and flufenoxuron, respectively. The latter value was not significant, and the field rate of flufenoxuron killed over 97% of the resistant larvae while
diflubenzuron had no effect. Sauphanor et al. (1998 (a)) concluded that "more importantly for resistance management, the resistance of different target instars to each compound [of benzoylphenylurea insecticides] has to be considered when establishing control strategies".
C. Resistance to diflubenzuron, deltamethrin, and phosalone occurred in the strain [of codling moth, Cydia pomonella (L.)] obtained from the orchard protected mainly with pyrethroids during the last 5 yr. Selecting this strain with deltamethrin for 7 generations resulted in a 96-, 6-and 3-fold increase in the resistance to diflubenzuron, deltamethrin, and phosalone,
respectively. This reveals a cross-resistance to these different insecticides in this selected strain, which also exhibited a resistance to teflubenzuron, tebufenozide, bifenthrin, and lambda-cyalothrin. Selection with diflubenzuron also resulted in a high resistance to diflubenzuron but a lower resistance to pyrethroids compared with the strain selected with deltamethrin. A decreased efficacy of azinphos methyl was observed on the 3 selected strains. The simultaneous resistance to several classes of
insecticides in these populations suggests that the implementation of a rotation program to delay resistance development will be difficult, and points to the need for improving alternative control methods such as microbiological insecticides or mating disruption (Sauphanor, 1998 (b)).
D. The efficacy of abamectin (Agrimec(R)) and teflubenzuron (Nomolt(R)) was assessed by leaf-dip bioassay against larvae of the diamondback moth, Plutella xylostella Linnaeus from a population (SERD3) collected originally in lowland Malaysia in December 1994. Evidence for resistance to both abamectin and teflubenzuron was found in the F-7 generation (LC50, ratio of
60 and 24 respectively compared with a laboratory, insecticide-susceptible strain). Selection of sub-populations of SERD 3 (Fi-Fy) with abamectin and teflubenzuron increased the LC50 ratio to 220 and 360 respectively and estimates of realised heritability [h2] were high (c. 0.8 and 0. 9) for both compounds. There was no cross-resistance between these compounds in
the abamectin and teflubenzuron-selected sub-populations but some indication of negatively-correlated resistance. Topical application of the synergists piperonyl butoxide, S, S, S-tributylphosphorotrithioate and maleic acid diethyl ester to the laboratory strain had no significant effect on the toxicity of abamectin or teflubenzuron in subsequent leaf-dip
assays (Iqbal and Wright, 1997).
Sea lice became immune to Ivermectin - another substance inadequately researched. SEPA are aware of this (SEPA. 1999).

Thus a range of target organisms have been shown to develop resistance to teflubenzuron. In addition, cross-resistance is developed with other BPUs.
Sauphanor et al. (1998a) concluded that:
- "the resistance of different target instars to each compound [of benzoylureas insecticides] has to be considered when establishing control strategies".
Sauphanor et al. (1998b) also concluded that: - the simultaneous resistance to several classes of insecticides in these
populations suggests that the implementation of a rotation program to delay resistance development will be difficult, and points to the need for improving alternative control methods such as microbiological insecticides or mating disruption."
SEPA (1999) is aware of the failure of sea lice control using compounds in which resistance is developed (Dichlorvos). In view of the readily developed resistance of target organisms to teflubenzuron, the "carpet bombing" approach will be short term and doomed to failure after inflicting unknown damage on non-target organisms.

Q. 6.1. Has the differential susceptibility of sea lice instars to different BPUs been studied? If not, why not?
Q. 6.2. Has a rotation programme for BPUs been devised? If not, why not?
Q. 6.3. Why is the biological control of sea lice with wrasse not promoted by SEPA?
Q. 6.4. Has a sea lice control strategy has been designed at all?

7. Biodegradability and sediments
Teflubenzuron is not readily biodegradable and is partially soluble in water (Trouw Aquaculture, 1993). Teflubenzuron is toxic to over three quarters of all known species in the animal kingdom. These include the Annelida and other species that are involved in bioturbation of sediments.The prima facie evidence suggests that after the use of teflubenzuron the sediments will be azoic, bioturbation will be greatly reduced, if not totally inhibited, with a consequent spread of the benthic impact zone.
Teflubenzuron will not be biodegraded and will continually dissolve into the water column with as yet unknown lethal and semi-lethal effects on zooplankton.

8. Monitoring
SEPA require the discharger to monitor in accordance with annex to assess the impact on:
- sediment;
- water quality;
- biology of controlled waters (the Loch).
The annex requires a photographic or video survey in the vicinity of the premises to be taken every 2 years.
SEPA advises that the farm should not discharge if another in the loch has done so within the preceding 3 hours.
Q. 8.1. As most lochs have a water turnover of 3 or 4 days, the figure of three hours would appear to be grossly inadequate, what studies is it based on?
Q. 8.2. In view of the gross abuses with Ivermectin (SEPA, 1999) and concerns regarding unregulated use of cheaper on what basis does SEPA believe that the salmon industry can be relied upon to self-police?
Q. 8.3.  How does a photographic or video survey in the vicinity of the premises possibly satisfy the requirements outlined above?
Q. 8.4. What guarantee does SEPA have that the survey was taken in the area and at the time specified? Are we back to self-policing?

9. Conclusions
Teflubenzuron is a chitinase inhibitor. Over three quarters of all known animal species produce chitin. Teflubenzuron is probably lethal to them all.
Target organisms have been shown to develop resistance to teflubenzuron.
Sea lice became resistant to Dichlorvos (Ivermectin) and will probably become resistant to teflubenzuron. The use of teflubenzuron is then,  a short term, dangerous policy. In view if the strategies recommended for its use in insect control and the known biological control of sea lice, it is apparent that SEPA does not have a long term sea lice control strategy.
SEPA's intention to monitor the effects of teflubenzuron and other sea lice treatments by Post Authorisation Assessment of the Environmental Impact of Sea Lice Treatments Project (PAAP) over a five year period is not best practice, exercising the precautionary principle or fulfilling SEPA's remit to 'protect the environment'. One only has to imagine the sentiments that
would be expressed if the nuclear industry were to use the same basis to dump radioactive wastes at sea. However it does allow the Salmon Aquaculture industry to utilise teflubenzuron for a five year period with no knowledge of the environmental effects and no criticisms as research is on-going. SEPA will be seen to be doing something, however inadequate. In addition, the five major institutions that are being funded, with taxpayers money, to conduct these studies are unlikely to criticise the use of Calicide and watch funds dry up.
Using Ivermectin as an example, then at the end of the five year period, when the environmental effects of its use are known, teflubenzuron will no longer be in used as sea lice will be resistant to it. The toxic wastes under salmon farms will continue to dissolve teflubenzuron into the water column for years to come.
There is much research to be done BEFORE teflubenzuron is considered to be licensed as a sea lice control agent.  It would appear that the lessons of environmental and economic damage caused by the release of inadequately researched toxic compounds into aquatic environments have not been learned by SEPA. The list of such compounds is long, it includes DDT, PCB's and TBT. Teflubenzuron must not be allowed to join them.

 References

ApladaSarlis, P.G., Miliadis., G.E., Tsiropoulos, N.G. 1999. Dissipation of teflubenzuron and triflumuron residues in field-sprayed and cold-stored pears. Journal of agricultural and food chemistry, Vol. 47, No. 7, pp.
2926-2929.

Barnes, R.D. 1987. Invertebrate Zoology. Saunders College Publishing, pp 890.

Benninger, P.G. & Le Pennec, M., 1991. Functional anatomy of scallops. In Scallops: biology, ecology and aquaculture (Ed. Shumway, S.), Elsevier Press.

Castane, C., Arino, J., Arno, J. 1996. Toxicity of some insecticides and acaricides to the predatory bug Dicyphus tamaninii (Het: Miridae). Entomophaga, Vol. 41, No. 2, pp. 211-216.

Consoli, F.L., Parra, J.R.P., Hassan, S.A. 1998. Side-effects of insecticides used in tomato fields on the egg parasitoid Trichogramma pretiosum Riley (Hym., Trichogrammatidae), a natural enemy of Tuta absoluta (Meyrick) (Lep., Gelechiidae). Journal of Applied Entom ology, Vol. 122, No. 1, pp. 43-47.

Furlong, M.J., Verkerk, R.H.J., Wright, D.J. 1994. Differential effects of the acylurea insect growth-regulator teflubenzuron on the adults of 2 endolarval parasitoids of Plutella xylostella, Cotesia plutellae and Diadegma semiclausum. Pesticide Science, Vol. 41, No. 4, pp. 359-364.

Hiemstra, M., Toonen, A., DeKok, A. 1999. Determination of benzoylphenylurea insecticides in pome fruit and fruiting vegetables by liquid chromatography with diode array detection and residue data obtained in the Dutch national monitoring program. Journal of AOAC International, Vol. 82, No. 5, pp. 1198-1205.

Iqbal, M., Wright, D.J. 1997. Evaluation of resistance, cross-resistance and synergism of abamectin and teflubenzuron in a multi-resistant field population of Plutella xylostella (Lepidoptera: Plutellidae). Bulletin of Entomological Research, Vol. 87, No. 5, pp. 481-486.

Koerts, J., Soffers, A.E.M.F., DeKraker, J.W., Cnubben, N.H.P., Rietjens, I.M.C.M. 1997. Metabolism of the insecticide teflubenzuron in rats. Xenobiotica, Vol. 27, No. 8, pp. 801-817.

Mikolajczyk, P., Oberlander, H., Silhacek, D.L., Ishaaya, I., Shaaya, E.1994. Chitin synthesis in Spodoptera frugiperda wing imaginal disks. 1.Chlorfluazuron, diflubenzuron, and teflubenzuron inhibit incorporation but not uptake of [c-14] n-acetyl-d-glucosamine. Archives of insect biochemistry and physiology, Vol. 25, No. 3, pp. 245-258.

Sauphanor, B., Bouvier, J.C. 1995. Cross-resistance between benzoylureas and benzoylhydrazines in the codling moth, Cydia pomonella. Pesticide Science, Vol. 45, No. 4, pp. 369-375.

Sauphanor, B., Brosse, V., Monier, C., Bouvier, J.C. 1998 (a). Differential ovicidal and larvicidal resistance to benzoylureas in the codling moth, Cydia pomonella. Entomologia experimentalis et applicata, Vol. 88, No. 3, pp. 247-253.

Sauphanor, B., Bouvier, J.C., Brosse, V. 1998 (b). Spectrum of insecticide resistance in Cydia pomonella (Lepidoptera: Tortricidae) in southeastern France. Journal of Economic Entomology, 1998, Vol. 91, No. 6, pp.1225-1231.

SEPA, 1998. Policy No. 29. Calicide (Teflubenzuron) authorisation for use as an in-feed sea lice treatment in marine cage salmon farms. Risk Assessment, EQS and Recommendations.

SEPA, 1999. Perspectives on the environmental effects of aquaculture.Au.Mackay, D.

Sterk, G., Hassan, S.A., Baillod, M., Bakker, F., Bigler, F., Blumel, S.,Bogenschutz, H., Boller, E., Bromand, B., Brun, J., Calis, J.N.M., CoremansPelseneer, J., Duso, C., Garrido, A., Grov., A., Heimbach, U., Hokkanen, H., Jacas, J., Lewis, G., Moreth, L., Polgar, L., Roversti, L., SamsoePeterson, L., Sauphanor, B., Schaub, L., Staubli, A., Tuset, J.J.,
Vainio, A., VandeVeire, M., Viggiani, G., Vinuela, E., Vogt, H. 1999. Results of the seventh joint pesticide testing programme carried out by the IOBC/WPRS-Working Group 'Pesticides and Beneficial Organisms'. Biocontrol, Vol. 44, No. 1, pp. 99-117.

Trouw Aquaculture (A Nutreco Company). 1993. Safety data sheet. NOMOLT technical material.

Tsiropoulos, N.G., ApladaSarlis, P.G., Miliadis, G.E. 1999. Evaluation of teflubenzuron residue levels in grapes exposed to field treatments and in the must and wine produced from them. Journal of agricultural and food chemistry, Vol. 47, No. 11, pp. 4583-4586.
 

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