Prevention of blowfly strike on lambs with the insect growth regulator dicyclanil

Abstract

In three multicentered field trials run during 1995 to 1997, involving a total of 12,928 lambs, the preventive effects on blowfly strike of a ready-to-use 5 per cent dicyclanil pour-on formulation and of a ready-to-use 6 per cent cyromazine pour-on formulation were compared with untreated controls for periods of up to 22 weeks. Their efficacy was assessed by calculating the consolidated cumulative strike rate for each treatment group and the consolidated percentage reduction of flystrike achieved by the two formulations. The consolidated cumulative strike rate for all three years together reached 29.2 per cent for the untreated control lambs at week 22, 2.8 per cent for the dicyclanil-treated lambs at week 22, and 6.9 per cent for the cyromazine-treated lambs at week 20. The consolidated cumulative percentage reduction of blowfly strike remained above 89 per cent for the dicyclanil-treated lambs. For the cyromazine-treated lambs the consolidated cumulative percentage reduction of blowfly strike reached 90 per cent during weeks 9 to 10, and 80 per cent during weeks 11 to 12.

Insect growth regulator cross‐resistance studies in field‐ and laboratory‐selected strains of the Australian sheep blowfly, Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae)

“…Trials in the Netherlands , New Zealand (Nottingham et al . 2001), the United Kingdom (Lonsdale et al . 2000) and South Africa demonstrated the effectiveness of dicyclanil in preventing strike on various sheep breeds with different wool types.…”

Survival advantage of cyromazine‐resistant sheep blowfly larvae on dicyclanil‐ and cyromazine‐treated Merinos

“…Moderate rainfall can move the insecticide to skin level, thereby enhancing activity, but excessive rainfall can equally leach cyromazine from the fleece and reduce its effectiveness. Dicyclanil is reported to be less affected by rainfall, although there has been a suggestion that dicyclanil may be translocated from the application site . It is unclear whether the absolute periods of protection reported here were influenced by rainfall, but even if they were, the relative periods of protection against strike by the susceptible F2011 and resistant NS strains are clear.…”

Strategic use of crutching and dicyclanil to protect unmulesed sheep against breech strike

“…Resistance has been confirmed in L. cuprina to a number of these groups, which can significantly reduce the period of protection below label claims 9,10 . However, tests with dicyclanil indicate protection periods significantly in excess of 12 weeks and potentially up to 24 weeks 11–14 . This insecticide was therefore used for the studies reported here.…”