Wollemia nobilis (Wollemi Pine) - Biosecurity New Zealand

App 3.3.11 Analysis of measure efficacy: Chemical Treatment for Mite Infestations
App 3.3.11.1 Abamectin
Abamectin, a contact and stomach acaricide, belongs to the organochlorine chemical group.
Lester and Lunn (2003) indicated that this acaricide has shown efficacy on motile stages only
of Eutetranychus banksi (Texas citrus mite), Tetranychus kanzawai (Desert spider mite),
Tetranychus neocaledonicus, and Tetranychus urticae (Two spotted spider mite), and
recommended an application rate of 180 mg a.i. per litre of water with a 10-14 days retreatment
to manage the lack of efficacy on mite eggs.
Knowles et al. found that abamectin and the other organochlorines tested were inactive
against the bulb mite (Rhizoglyphus echinopus). Herron et al. (1996) determined that the
LC99.9 against Polyphagotarsonemus latus (banks) (Acari: Tarsonemidae) adults was 0.1 mg
a.i. per litre. Humeres and Morse (2005) found maximum LC90 rates for Oligonychus
perseae (Acari: Tetranychidae) adults at the upper 95% confidence limit as 3.3 mg a.i. per
litre of dip. Nauen et al. (2001) found maximum LC95 rates for Tetranychus urticae (Acari:
Tetranychidae) first-motility stage larvae at the upper 95% confidence limit as 0.21 mg a.i.
per litre of spray.
App 3.3.11.2 Dicofol
Dicofol, a non-systemic acaricide with contact action, belongs to the organochlorine chemical
group. Lester and Lunn (2003) noted that this acaricide has shown efficacy in field situations
on Eutetranychus banksi (Texas citrus mite), Tetranychus kanzawai (Desert spider mite),
Tetranychus neocaledonicus, and Tetranychus urticae (Two spotted spider mite). Lester and
Lunn (2003) also noted that resistance to dicofol is present in some mite populations. If the
mite species is likely to be resistant in the country of origin, an alternative treatment should
be used instead of, or in combination with dicofol.
Herron et al. (1996) determined that the LC99.9 against Polyphagotarsonemus latus (banks)
(Acari: Tarsonemidae) adults was 1 g a.i. per litre. Dagli and Tunc (2001) demonstrated that
resistance to dicofol in agricultural populations of Tetranychus cinnabarinus (Acari:
Tetranychidae) could, depending on the bioassay, range from as much as 17 to 59 fold.
Maximum LC95 results obtained at the upper 95% confidence limit were as high as 8.9 g a.i.
per litre of the applied acaricide. Similar levels of resistance have also been reported for
Tetranychus urticae. Kumar and Singh (2004) found that dicofol was effective on
Tetranychus urticae eggs at relatively low concentrations.
App 3.3.12 Recommendations for measure: Chemical Treatment for Mite
Infestations
Table App 3.8 below examines the efficacy information for each of the active ingredients
listed above.
Import Risk Analysis: Wollemia nobilis (Wollemi Pine) Araucariaceae Nursery Stock from Australia 14 March 2008 Page 161 of 193