Wollemia nobilis (Wollemi Pine) - Biosecurity New Zealand

Active ingredient Comment on Efficacy
Tebufenozide
(see 3.3.8.9)
Thiacloprid
(see 3.3.8.10)
The studies above provided large discrepancies on the toxicity of tebufenozide
to P. xylostella. However, since 90% mortality was obtained for the label rate
in one of the studies, it seems advisable to use 2x label rate to add a safety
margin based on the available information. Since all other lepidopteran pests
had LC90 values that were considerably lower, a tebufenozide concentration of
3.0 g a.i. per litre is likely to be effective against lepidopterans. Nonetheless, it
is advisable to carry out complementary treatment with a pesticide from
another chemical group. A foliar spray application should not be permitted.
Until adequate information can be obtained, this chemical compound should no
longer considered for quarantine purposes in New Zealand.
It is recommended that no single insecticide is adopted for treatment, and that the more
efficacious dip treatment be the standard method of application. In addition, ideally the risk
analysis should indicate whether certain resistant strains of high risk pests occur in the
country of origin of a particular commodity, so that the recommended measures may exclude
particular pesticides as possible mitigating measures. It is also likely that insecticide dipping
would have reduced efficacy against insects such as wood borers that have life stages deep
within plant tissue. A research project is also recommended to address issues relating to the
lack of efficacy data underpinning the currently prescribed treatments for nursery stock.
In summary therefore:
o Deltamethrin, pirimiphos-methyl and thiachloprid should not be used at this stage for
quarantine purposes, until adequate efficacy information is available;
o Fenvalerate should no longer be used as a prescribed chemical treatment, since its
permit has been revoked by the EPA (USA);
o The remaining pesticides, namely acephate, chlorpyrifos, and dimethoate
(organophosphorous); carbaryl (carbamate); imidacloprid (neonicotinoid); spinosad
(spinosyns); and tebufonized (diacylhydrazine), are adopted in chemical treatments of
nursery stock for quarantine purposes, but using the revised rates until adequate
efficacy data are available;
o A combination of pesticides from two different chemical groups (organophosphorous,
carbamate, neonicotinoid, spinosyns, or diacylhydrazine) should be applied to
maximize efficacy and mitigate potential issues with insect resistance;
o Nursery stock should be treated again 10-14 days after the initial treatment to manage
any potential lower treatment efficacy against untested insects or life stages;
o Nursery stock entering a post-entry quarantine facility should not begin their
quarantine period for insect contamination until the chemical residues have
sufficiently dissipated or become inactive (considered here to be equivalent to the
aerobic soil half life - see table App 3.6). Care should be taken to ensure that
adequate account is taken in the quarantine period of nursery stock subjected to a prequarantine
application of insecticides with extended residual activity.
o Scientific research is required to address issues relating to:
Page 158 of 193 14 March 2008 Import Risk Analysis: Wollemia nobilis (Wollemi Pine) Araucariaceae Nursery Stock from Australia