South Africa W.Murcott Canopy Management Study tour

Introduction

A W.Murcott mandarin study tour was conducted in May 2024, visiting W.Murcott orchards in the three main production regions of the Western and Eastern Cape of South Africa ; Citrusdal, Robertson and Addo/Sundays River Valley (Figure 1.) The focus of the study tour was to learn about canopy management strategies to maintain productivity. Eleven farms were visited, and 6 videos are presented of farm visits and technical discussions that demonstrate the main messages of the study tour. The videos range from 2 to 10 minutes and are listed below.

This video is an outcome of the Hort Innovation Afourer best practice canopy management project CT19002.

Key learning points

The key learnings points from the study tour are summarised below and the detailed information is presented in the videos.

• Key Practices: Production is maintained at 60 to 80 t/ha by using a combination of practices being pruning (watershoot and regrowth management; triangular tree shape), crop monitoring, and using plant growth regulators for fruit thinning, flower regulation and canopy growth suppression. Most growing regions experience high spring winds and overhead netting is popular as a method to reduce wind blemish and increase 1st grade packout.
• Tree shape: In narrow row spacings (6 m or less), trees are pruned in a triangular tree shape (Figure 2, Figure 3, also termed as pyramid or Xmas tree). This shape produces a compact and manageable tree with good consistent yields.
• Canopy management: All growers regarded water shoots as the main problem of W.Murcotts and their solution was to remove them from the canopy. Hand pruning of limbs and branches occurs straight after harvest (prior to flowering), this pruning aims to maintain a triangular tree and limb structure. Regrowth is managed by tipping and removing shoots when they reach about 20-40 cm (2-3 times per season, late spring to summer). Tipping regrowth will force the shoot to grow 2-4 side shoots . Regrowth is thinned and tipped early in the season to prevent water shoot growth and to transform water shoots into productive complex branches.
• Growth regulators: Uniconazole (Sunny) is extensively adopted as a soil drench. It is applied during flower induction (late April/early May) to increase flower numbers and at early spring flush (about 2 cm) to reduce flush elongation (reduce pruning) and increase fruit set. Gibberellic acid is used at 80-100% petal fall to increase fruit set. Growth regulators, diclorprop-p and 3,5,6-TPA, are used to thin and increase the size of fruit.
• Nutrition: Nutrient application principles and amounts varied significantly between growers. Basic programs applied 150 to 180 kg of nitrogen per ha per annum in weekly fertigation during spring and early summer.
• Labour: Labour is abundant costing about $2.20 AU per hour at the minimum wage and rising to about $3.50 AU per hour for specialised practices.

Video list

• 1) AGL Farms, Citrusdal
  6 min: Gerrit van der Merwe (Production manager) describes how he converted W.Murcott orchards pruned in a V shape tree to a triangular tree shape.
• 2) Mouton Citrus, Citrusdal
  5 min: Ryan Arnold and Steven Falivene present discussion with orchard owner CP Mouton, of Mouton Citrus.
• 3) Gert de Vries, Suiderland plase, Robertson
  9 min: Steven Falivene presents discussion with orchard production manager Gert de Vries, on the orchard canopy management practices.
• 4) Dome Citrus, Robert Brown, Robertson
  11 min: Ryan Arnold and Steven Falivene present discussion with orchard production manager, Robert Brown, on the orchard canopy management practices.
• 5) Indigo Citrus, Danie Grabe, Robertson
  2 min: Danie Grabe (production manager) describes how he is converting a W.Murcott double tramway orchard to a single row planting and utilising triangular tree pruning.
• 6) Growth regulators; Paul Cronje, CRI, Stellenbosch University
  10 min: Steven Falivene interviews Citrus Research International (CRI) research leader at Stellenbosch University about the use of growth regulators in South African citrus.

1) AGL Farms, Citrusdal
6 min: Gerrit van der Merwe (Production manager) describes how he converted W.Murcott orchards pruned in a V shape tree to a triangular tree shape.

2) Mouton Citrus, Citrusdal
5 min: Ryan Arnold and Steven Falivene present discussion with orchard owner CP Mouton, of Mouton Citrus.

3) Gert de Vries, Suiderland plase, Robertson
9 min: Steven Falivene presents discussion with orchard production manager Gert de Vries, on the orchard canopy management practices.

4) Dome Citrus, Robert Brown, Robertson
11 min: Ryan Arnold and Steven Falivene present discussion with orchard production manager, Robert Brown, on the orchard canopy management practices.

5) Indigo Citrus, Danie Grabe, Robertson
2 min: Danie Grabe (production manager) describes how he is converting a W.Murcott double tramway orchard to a single row planting and utilising triangular tree pruning.

6) Growth regulators; Paul Cronje, CRI, Stellenbosch University
10 min: Steven Falivene interviews Citrus Research International (CRI) research leader at Stellenbosch University about the use of growth regulators in South African citrus.