In PCT system objections to a WIPO application can be registered using Third Party Observation method.
This system allows third parties to make observations through ePCT
public services referring to prior art which they believe to be
relevant to the question of whether the invention claimed in the
international application is novel and/or involves an inventive step.
There is no fee for this service. For a comprehensive user guide, see
ePCT Third Party Observations
Third party observations may be submitted at any time after the date of publication of the international application and before the expiration of 28 months from the priority date, provided that the application is not withdrawn or considered withdrawn.
Answer to query:-
patent application list very general method of propagation but as per inventor use of specific polymer makes it novel as none of the prior art uses the said invented polymer.
since 28 months as past no observation can be made in PCT but in case you are interested you can file observation in countries application has entered (i.e. AU and US).