# Copper Defoliation Nectarine Trial in Hawkes Bay – Stone Fruit

- Link: https://rd2.co.nz/trial/copper-defoliation-trial-in-hawkes-bay/
- Published: 2019-09-07T23:30:45+00:00
- Author: rsf_admin

> Biomin Copper gave excellent defoliation at 95% after one application.

Copper Oxychloride is a very expensive product since it did not defoliate the trees;
however, growers who initially compare product prices would choose Copper Oxychloride
over Biomin Copper as it appears cheaper.

It is important to never choose a product on the price of a container alone, application
rate and the number of applications plus the effectiveness should always be considered.

The use of Copper Oxychloride based on price would be considered false economy since
the aim of applying coppers at the end of the season to defoliate stone fruit trees
is to alleviate the spread of organisms causing Bacterial Blast infection through
susceptible leaf scar wounds.

Since Copper Oxychloride was not effective at giving appropriate defoliation levels
further applications will be required. Copper oxychloride is a heavy metal that 
contaminates soil and kills beneficial organisms whilst Biomin Copper is a systemic
copper that leaves no residue, enters the plant and is used nutritionally without
increasing soil heavy metal levels.

There is an added potential issue of residue contamination to the meat of grazing
sheep after a Copper oxychloride application.

[View the full trial here.](https://rd2.co.nz/wp-content/uploads/2018/02/Comparing-Coppers-for-Defoliation-EMAILpdf.pdf)