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 Paul Cronje and Keith Lesar (CRI)

Peteca spot of lemons, characterized by random, darkened depressions or sunken areas in the rind, can occur as early as 3-5 days after harvest. The project is currently focused on understanding the impact of postharvest treatments viz. harvesting, general handling of fruit, degreening, waxing and storage. Information from these experiments is used to determine handling protocols to manage and reduce the risk of peteca spot development.

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 • Scab • Black pit

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 – 1 mL Back – 2 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) THANK YOU FOR YOUR ATTENTION