14 Sep 2011

Sprays may not work against PSA, scientist warns

2:01 pm on 14 September 2011

Nathan Balasingham from Pukekohe says copper is phototoxic to the vines when used in spring and reduces bud development.

He is also concerned about the kiwifruit marketer Zespri's recent recommendation for growers to use the antibiotic streptomycin before flowering to control PSA.

Mr Balasingham says it won't be effective because even one bacteria cell left after spraying can overnight divide into a huge colony.

He recommends actions such as removing dead tissue from plant, stopping practices that weaken the vine such as ring-barking, reducing fertiliser use and take action that strengthens the plants.

Mr Balasingham says growers should also consider using a spray which improves the immune system of the kiwifruit vine, as well as productivity.