The NZ EPA has placed by red alert restrictions on the use of products containing the chemical
herbicide Chlorthal-dimethyl, used to control broad leaf weeds and grasses in horticulture.
1. The substance can only be used as a pre-emergent herbicide on allium crops as a single
treatment per calendar year.
2. The substance must not be applied at a rate greater than 10.5 kg ai/ha.
3. The substance must not be applied within 30 metres of any track or road accessible to the
public, public hut, dwelling, township, beach, or anywhere there is recreational activity in
the area.
4. The substance must only be applied by a low boom sprayer using coarse (or larger) spray
droplets, as defined by the American Society of Agricultural and Biological Engineers
ASABE Standard (ASAE S572).
5. The substance must not be applied when wind speeds are less than 3 km/h or more than
20 km/h as measured at the application plot.
6. No mixing, loading, or application of the substance by pregnant individuals or individuals
who may be pregnant.
7. Pregnant individuals or individuals who may be pregnant must not enter the application plot
for five days post application.
8. Prior to application, signs must be erected at every vehicular and pedestrian point of entry
to the application plot and the signs must remain in place for a minimum of five days post
application of the substance.
9. They must indicate the name of the hazardous substance which has been applied.
10. The signs should also warn of the risk to foetal development from exposure of pregnant
individuals and that pregnant individuals or individuals that may be pregnant must not enter
the application plot until [DATE], where [DATE] is at least five days after application of the
substance.
11. The signs must be compliant with the requirements specified in regulation 2.5(2)(c) of the
Health and Safety at Work (Hazardous Substances) Regulations 2017.
Responsible Care NZ understands that in New Zealand there are three products registered
by ACVM containing the chemical — Dacthal, Deramot Xtra and Chlor-Back 75WG — which
must now be managed in accordance with EPA controls..