Relative efficacy of organophosphorus insecticides against susceptible and resistant strains of the strike blowflyLucilia cuprina(Calliphoridae) in New Zealand sheep

Wilson, Joanne A. P.; Heath, Allen; Stringfellow, L.; Haack, N. A.; Clark, Andy

doi:10.1080/00480169.1996.35970

Cited by 8 publications

(3 citation statements)

References 13 publications

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“…This is comparable with protection periods afforded in the Þeld by diazinon, an organophosphorus insecticide, but somewhat less than the same chemical achieved in implant trials (Wilson et al 1996). As the potency was reduced, we frequently observed examples of intermediate effect in which the larvae survived for a day or so but did not cause visible pathology.…”

Section: Discussionsupporting

confidence: 51%

“…A mixture of F 2 and F 3 Þeld strains of L. cuprina Þrst instars Ͻ4 h old was used to establish a ßy strike bioassay ("implants") on each of the treated and control sheep. The blowßy strains exhibited varying degrees of organophosphorus insecticide resistance (Wilson et al 1996). When active ßy strike established on a test animal (end point) it was removed from the trial.…”

Section: Preparation Of Sheep and Treatment Allocationmentioning

confidence: 99%

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Efficacy of Native and Recombinant Cry1B Protein Against Experimentally Induced and Naturally Acquired Ovine Myiasis (Fly Strike) in Sheep

Heath¹,

Broadwell²,

Chilcott³

et al. 2004

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Several hundred strains of Bacillus thuringiensis (Bt), isolated in New Zealand from samples of soil and sheep fleece, were tested for toxicity to larvae of the blowfly Lucilia cuprina Wiedemann. Characterization of the Bt strains revealed that three of the more active strains produced Cry1Ba (an insecticidal protein present in Bt mother cell crystal inclusion) that was toxic to blowflies. These strains were evaluated for the ability to prevent experimentally induced fly strike in a bioassay by using first instars. Results with undiluted spore/crystal preparations were variable, but they generally prevented fly strike on sheep maintained on pasture for 3-6 wk. Spore viability was satisfactory throughout the trials and environmental factors (e.g., precipitation and UV radiation) seemed to have minimal effect on persistence. The loss of fly strike protection in these experiments correlated with the movement of spore/crystal toxicity away from the skin as a result of wool growth. Solubilized protein preparations were not as potent as spore/crystal preparations and fly strike protection lasted only from 1 to 3 wk. Vegetative forms of the Cry1Ba-producing strains of Bt did not establish on the fleece of sheep, did not produce significant sporulation, and no protection against fly strike was achieved. Escherichia coli expressing recombinant Cry1Ba protein was toxic to larvae in vitro but did not effectively protect sheep from fly strike because blowfly larvae were able to establish readily 8 d posttreatment. In a single field experiment involving 80 sheep per group, a spore/crystal preparation from a Bt strain expressing Cry1Ba provided less protection from naturally acquired fly strike than afforded by a commercially available dip.

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Section: Discussionsupporting

confidence: 51%

Section: Preparation Of Sheep and Treatment Allocationmentioning

confidence: 99%

Efficacy of Native and Recombinant Cry1B Protein Against Experimentally Induced and Naturally Acquired Ovine Myiasis (Fly Strike) in Sheep

Heath¹,

Broadwell²,

Chilcott³

et al. 2004

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“…Blowfly control relies largely on insecticides 9,10 . Strains of L. cuprina have demonstrated an ability to develop resistance to these chemicals 5,7,11,14,22,23 . International trade agreements increasingly strive to control harmful chemical residues in products.…”

Section: Introductionmentioning

confidence: 99%

A preliminary evaluation of a sheep blowfly trap in the Western Cape

Scholtz¹,

Cloete²,

Laubscher³

et al. 2000

J. S. Afr. Vet. Assoc.

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An insecticide-free sheep blowfly trapping system, utilising a synthetic lure, was evaluated at 4 localities in the Western Cape. Control sites, where no suppression was practised, were identified for each locality. The blowfly population was monitored for 48 hours monthly at each of the localities. Five to 7 suppression traps at the respective localities were identified for this purpose. Three to 10 traps were set monthly for monitoring in the control areas. Trapping resulted in the suppression (P <0.01) of the Lucilia population at Caledon, where a large area of approximately 50 km 2 was trapped. The suppression area of all the localities was =850 ha. At Elsenburg, blowfly numbers were low. There was a strong suggestion of a general reduction in the Lucilia numbers at this locality. Trapping failed to reduce Lucilia numbers at Tygerhoek and Langgewens. Lack of control over the influx of Lucilia from adjacent sheep-producing areas probably contributed to this result. The observed response at Elsenburg was probably due to its situation in a predominantly wine-growing area. Most of the blowflies recovered from the control traps during the month with the highest yield at the respective localities belonged to the genus Lucilia. The results obtained at Caledon and published reports suggest that large-scale trapping of Lucilia spp. may play a role in an integrated pest management system for blowflies

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A review of mulesing and other methods to control flystrike (cutaneous myiasis) in sheep

Phillips

2009

Anim. welf.

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Flystrike (cutaneous myiasis) in sheep has the potential to have a major impact on the welfare of significant numbers of sheep worldwide, but particularly in Australia. The main control method used in Australia, the mulesing operation to remove folds of skin from the hindquarters of the sheep, is effective in controlling the disease, but will be terminated from 2010 as a result of concerns that the operation itself has too great a negative impact on sheep welfare. Alternative treatment methods are considered, and it is proposed that they need to be appraised for each farm separately, based on the conditions prevailing and the potential to apply the different treatments. Sheep are predisposed to flystrike if their fleece is wet or contaminated with faeces or urine. Monitoring and awareness of the weather conditions will enable farmers to strategically treat their sheep with insecticides, or to observe them and treat affected animals more regularly. Frequent removal of wool by crutching, dagging and shearing will aid wool desiccation after rainfall and decrease the likelihood of fleece contamination with excreta. Some control of diarrhoea can be achieved by good grazing management and treatment of diseases that predispose sheep to the disorder. Reducing fly populations can be achieved by the use of traps, and parasitoid wasps also offer some promise. Alternative methods of removing wool and wrinkles from the hindquarters of sheep, including the topical application of quarternary ammonium compounds, phenols, caustic soda or plastic clips, have yet to be proven to be effective, without severely impacting on the welfare of the animal as well as compromising operator safety. In the long term, the breeding of sheep without wrinkles or wool on their hindquarters offers the most likely method of control, although a small proportion of sheep are affected on other parts of their body.

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Relative efficacy of organophosphorus insecticides against susceptible and resistant strains of the strike blowflyLucilia cuprina(Calliphoridae) in New Zealand sheep

Cited by 8 publications

References 13 publications

Efficacy of Native and Recombinant Cry1B Protein Against Experimentally Induced and Naturally Acquired Ovine Myiasis (Fly Strike) in Sheep

Efficacy of Native and Recombinant Cry1B Protein Against Experimentally Induced and Naturally Acquired Ovine Myiasis (Fly Strike) in Sheep

A preliminary evaluation of a sheep blowfly trap in the Western Cape

A review of mulesing and other methods to control flystrike (cutaneous myiasis) in sheep

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