Netted apple orchard 2014 - 2015 season results and update

Demonstration treatments

A further treatment using drip irrigation under the netting was added to address the high tree vigour observed in the first season.  It is widely accepted that vigour negatively impacts the production of good quality fruit on Cripps Pink trees, affecting fruit size  and colour development, very important quality and marketing criteria.

Drip irrigation lines were installed either side of four rows of trees under the changeover from black and white net. The addition of drip irrigation brings the treatments being tested to five;

1. Black net, under tree sprinkler
2. White net, under tree sprinkler
3. DAFWA no net, under tree sprinkler
4. Grower no net, under tree sprinkler and
5. Drip irrigation under netting

Ten Cripps Pink trees within each area were tagged, intensively monitored during the season then harvested separately from the remaining crop. All thinning, pruning and tree management was done as per normal practice by the Lyster’s.  An independent irrigation system controlled remotely allowed for different irrigation scheduling for treatments as required.

The drip area was in between the buffer area of the netted treatments and comprised one row each of Cripps Pink and Fuji under black net and one row each under white.

The ten tagged trees from each treatment block were strip picked by DAFWA staff based on maturity (starch conversion tests) but not colour development, starting the 27 April 2015. The remainder of each treatment block (390 trees) were picked to commercial standards based on colour and maturity by the Lyster’s. The commercial harvest continued through May. The fruit in the commercial harvest were allowed slightly longer to develop colour and only fruit suitable for packing was picked by the Lyster’s.  The drip section has data only from the DAFWA strip pick harvest.

Average fruit numbers, from the 10 trees picked, varied between treatments with the no net grower treatment averaging 167 apples/tree. The black and white net and drip treatments all had similar fruit number of 198, 202 and 209 fruit per tree respectively.  The no net DAFWA treatment had significantly more fruit with an average of 301 fruit per tree.

All strip picked fruit from individual trees was manually graded as marketable and non-marketable based on the incidence of damage (bird damaged, sun damaged, bruising, marks, insects and disease). Fruit considered marketable was assessed against the Pink Lady standards. A subset was weighed, measured for diameter and tested for maturity (table 1). Non marketable fruit ranged between 18% in the no net grower treatment and 29% in the white net treatment.  The most common reason for non-marketable fruit was small fruit and dents, which increased as fruit numbers per tree increased, as expected.

# sunburn is a subset of non-marketable fruit.