When did spraying of international flights on arrival in Australia start again?

When did spraying of international flights on arrival in Australia start again? Came back from HNL on HA last week and on arrival at Sydney the plane was sprayed internally. This is the first time this has happened on an aircraft I've been on for at least 5 years???

It depends on the carrier... most airlines and aircraft have long term disinsection approvals... but if an aircraft hasn't had it done for a while, or its an aircraft that has expired, it may require the Top of Descent Spray prior to arrival in Australia.

Most airlines have that spray coming through the air conditioning system, Hawaiian does not so it is sprayed. 

I'm pretty sure application by air conditioning is a myth and am not familiar of any aircraft with an air conditioning system which can administer disinsection sprays.

Airlines which regularly fly to Australia, NZ or others requiring disinsection may choose to treat the aircraft with a residual spray. The spray sticks to every surface of the aircraft of the aircraft, rather than being airborne.

US Carriers in particular have difficulty completing residual sprays as the chemicals are banned in the US. Virgin Australia completes it's sprays in Abu Dhabi whilst United gets theirs done in Hong Kong.

A residual spray treatment lasts for about 70 days, so aircraft which have not been residually treated are treated by Top of Decent aersol sprays. This is a plant based disinsection spray and is generally safer than the residual treatments. Think about it, the residual sprays have to remain strong enough for 70 days...

Moral of the story: Don't lick the plastic on aircraft flying to Australia.

The only flight this has happened to me on was coming back from Dubai in 2010