Amistar fungicide trial

Completed, Fruit quality, Fruit rots, Plant protection chemistry

Start date: 2018

End date: 2021

A collaboration between Syngenta NZ and New Zealand Avocado to extend the NZ AMISTAR label to include disease claims for avocados was undertaken from 2018-2021. This included multiple efficacy, residue, crop safety and compatibility trials.

Regrettably these trials did not generate a data package to support the registration of Amistar for avocados. Efficacy and crop safety results were inconsistent. Residue results were above the limit of quantification (>0.01 mg/Kg), which would prevent market access to most countries New Zealand currently exports to.

Overseas trials have shown two applications of Amistar close to harvest are required to obtain good efficacy on avocados. This use pattern will result in residues that exceed both international market maximum residue limits (MRLs) and the default MRL for the New Zealand domestic market. To obtain residues acceptable to international and domestic markets requires an earlier use pattern, which will compromise efficacy.

As a result Syngenta and NZ Avocado have decided not to progress a label extension for AMISTAR into avocados in NZ at this stage. NZ Avocado will to continue to work on alternative fungicides for use in avocados.