Melpat International (Pty) Ltd Citrus Disorders 1. Post Harvest 2. - PowerPoint PPT Presentation

Melpat International (Pty) Ltd

Citrus Disorders 1. Post Harvest 2. Crop Management All controlled by Copper

Citrus Disorders – Post Harvest Most occur post harvest: 1. Injury caused by chilling process:  Shipments at -0.5ºC (insect sterilization)  Symptoms similar to frozen produce  Aim to improve rind condition during fruit development  more robust fruit Reference: Citrus Research International, South Africa

Citrus Disorders – Post Harvest 2. Rind Breakdown  Collapse of the oil glands  Aim:  Nutrient optimisation within tree and carbohydrate allocation, which determine rind condition  Handling Reference: Citrus Research International, South Africa

Citrus Disorders – Post Harvest 3. Peteca Spot: Reference: Citrus Research International, South Africa

Citrus Disorders – Post Harvest 4. Creasing (Albedo Breakdown):  Physiological Disorder, which results in a separation of cells  Aim:  Ca + Ga Sprays  Ga Timing which does not interfere without having a negative colour effect.  Bearing position and light manipulation Reference: Citrus Research International, South Africa

Crop Management – Controlled by Cu • Alternaria brown spot • Citrus black spot Alternaria alternata Guignardia citricarpa Reference: Citrus Research International, South Africa

Crop Management – Controlled by Cu • Sooty mold • Melanose Capnodium citri Phomopsis citri Reference: Citrus Research International, South Africa

Crop Management – Controlled by Cu • Black pit • Scab Elsinoe fawcetti Pseudomonas syringae Reference: Citrus Research International, South Africa

Crop Management – Controlled by Cu • Phytophthora brown rot Phytophthora nicotianae var. parasitica Reference: Citrus Research International, South Africa

Crop Management – Controlled by Cu • Botrytis on lemons Botrytis cinerea Reference: Citrus Research International, South Africa

Crop Management – Controlled by Cu • Bacterial canker Xanthomonas campestris Reference: Citrus Research International, South Africa

Crop Management – Controlled by Cu • Greasy spot • Septoria spot Septoria citri Mycosphaerella citri Reference: Citrus Research International, South Africa

Crop Management – Controlled by Cu • Pseudocercospora Pseudocercospora angolensis Reference: Citrus Research International, South Africa

Crop Management – Controlled by Cu • Mal secco Phoma tracheiphila Reference: Citrus Research International, South Africa

Crop Effect – Copper Blemish Copper Stippling – frequent spraying Photos courtesy of Dr. Tian Schutte (CRI)

Side Effects – not to be confused Darkening of blemishes Thrips Mites / Wind Reference: Citrus Research International, South Africa

Applying copper sprays:  Spraying time: Late March to Early April.  Always spray at the recommended rate of application and be sure leaves and fruit are well covered.  A second or third spray may be necessary if wet weather persists.  Preferably spray after mid morning when the fruit has warmed up.  Always use the recommended rate of wetting agents. If this is not done, the spray may remain in drops on the fruit and leaves.  Skirt trees and prune the inside of trees to maximise spray penetration, coverage and reduce disease buildup.  If sooty mould is a problem, add 500ml of spraying oil / 100 liters of water.  Some copper formulations may darken wind scars or insect marks.  DO NOT mix copper based sprays with other sprays as this may cause rind burn.  District variations

Reference: Citrus Research International, South Africa

Reference: Citrus Research International, South Africa

Front - 1 mL Reference: Citrus Research International, South Africa

Front - 2 mL Reference: Citrus Research International, South Africa

Front - 3 mL Reference: Citrus Research International, South Africa

Front - 6 mL Reference: Citrus Research International, South Africa

Back – 2 mL Back – 1 mL Back – 3 mL Back – 6 mL Reference: Citrus Research International, South Africa

Coffee stain effect Reference: Citrus Research International, South Africa

Effect of spray run-off Reference: Citrus Research International, South Africa

Botrytis cinerea on grapevine leaves Reference: Citrus Research International, South Africa

Botrytis cinerea on grapevine leaves Reference: Citrus Research International, South Africa

Ideal Water Volumes  Tree Size Dependent  Mature 2500 – 3200 lt/ha ( use wetting agent)

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