Managing Anthracnose in Olives

Anthracnose (Colletotrichum spp.)

Background:

Olive anthracnose is the most important fungal disease of olive fruits worldwide. It occurs in humid olive-growing areas of many countries and causes heavy yield losses and lowering of oil quality. In Australia Anthracnose is a moderate to major problem depending on climatic factors. Causes soft circular rots on the fruit, and at high humidity produces an orange slimy mass of spores on the fruit surface; commonly observed close to harvest when the fruit softens.

Transmission – survives on infected mummified fruit. Spores are spread by rain splash and wind, can infect ripe fruit from new spores within 4 days.  Anthracnose infected flowers can lead to reduced fruit quality and premature fruit drop that reduces yield. When pressed the diseased fruit produce a turbid and acidic (High FFA) reddish oil of poor quality (defects: Musty / Humid / Grubby); the oil can be downgraded to a quality less than EVOO standard.  Anthracnose is also problematic for table olives because of impact on taste and appearance.

Current APVMA Permits

Note: These PERMITS provide for the use of a product in a manner other than specified on the approved label of the product. Unless otherwise stated in this permit, the use of the product must be in accordance with instructions on its label.

Permit ID

Description

Date Issued

Expiry Date

Permit holder

Chem Group

MRL mg/kg

PER14908

Pyraclostrobin + Metiram (Aero) / Olives / Anthracnose

8-Jan-15

31-Mar-20

AOA

11 & M3

T1 & T2 (olives)

Withholding Period: 21 days.

 

Permit ID

Description

Date Issued

Expiry Date

Permit holder

Chem Group

MRL mg/kg

PER14580

Azoxystrobin (Amistar) / Olives / Anthracnose

23-May-14

31-Aug-19

AOA

11

T2 (olives)

Withholding Period: 21 days.

 

Permit ID

Description

Date Issued

Expiry Date

Permit holder

Chem Group

MRL mg/kg

PER11360

Copper (Copper present as Cupric Hydroxide, Cuprous Oxide, or Tribasic Copper Sulphate) / Olives / Fungal spots and rots including Peacock Spot and Anthracnose

24-Mar-2009

30-Nov-2021

AOA

M1

10 (fruits)

Withholding Period: 1 day.

 

Further details on chemical permits available at: https://portal.apvma.gov.au/permits

Note: Victoria is not included in the above 2 permits, as their Control-of-Use legislation does not require a permit to legalise this off-label use in this state.

In addition there are a number of registered (on label) copper oxychloride crop protectant products approved for use on olives:

Product Number

Description

Chemical group

Activity   

Comments

(Product # 63665, 68826, 59711)

Copper Oxychloride (CHEMTURA / CURENOX / OSPRAY)/ Olives / Olive Leaf Spot or Peacock Spot, Grey Leaf Spot, Fruit Round Spot, Anthracnose, Other general fruit rot.

M1

Contact, protectant

Registered. Commonly used in winter and spring.  2-4  applications/yr

Withholding Period: 1 day.

 

Further label and MSDS details on registered products is available at:  https://portal.apvma.gov.au/pubcris  

Note: The use of registered products must be in accordance with instructions on its label.

FURTHER INFORMATION ON ANTHRACNOSE CONTROL OPTIONS:

Current permit control option to move to label registration:

  • Pyraclostrobin + Metiram (Aero) – trial work funded from AgVet grants is currently underway with the aim of achieving label registration prior to expiry of the current permit (31/3/2020)

 

New Chemistry:

Additional chemicals with potential for control of anthracnose have also been identified from research by Associate Professor Robert Spooner-Hart from Western Sydney University (WSU). 

  • Fluopyram (Luna Privilege) – BSC On Label - Group 7 fungicide  - trial work for this chemical has also been approved for AgVet funding, due for completion 1/2/2020.

 

IMP and Anthracnose

According to plant pathologist Dr Vera Sergeeva (OliVera), successful management of anthracnose relies on understanding the conditions that promote disease development and the control measures taken to obtain olive oil of good quality

Integrated pest management (IPM) Integrated pest management (IPM) of anthracnose in olives involves managing yield and creating an environment less appealing to disease. The disease epidemiology and disease cycle play an important role in working out strategies for effective and timely management of anthracnose and in reducing the number of unnecessary fungicides applications.

Anthracnose is difficult to control after the symptoms appear, particularly when environmental conditions are favourable for infection. Environmental factors play an important role in managing diseases. Weather is a crucial in the development of anthracnose throughout the year, especially at flowering and prior to harvest. Optimum conditions for disease development depend on temperature, wetness, relative humidity and rain period. If these weather conditions prevail during flowering they cause severe flower infection and consequently, reduce fruit set. Latent infection of developing fruit in spring may permit survival of the pathogen in the following summer even under hot conditions (Moral et al., 2008). Epidemics occur when olive varieties susceptible to the anthracnose pathogens grow under warm and humid conditions. Infection can be controlled in a number of ways (Sergeeva, 2011a; 2011b). Effective disease control is obtained through a combination of methods, including prevention, observation and intervention.


Dr Vera Serveeva has kindly provided the following informative Powerpoint presentation covering diagnostic and research work on Anthracnose including Integrated Pest Management Strategies.

Anthracnose in Olives - Symptoms, Disease Cycles & Management

 

As well as the below paper on Anthracnose in olives: symptoms, disease cycle and management

Sergeeva V. | Proceedings of the 4th International Conference on “olive culture and biotechnology of olive tree products” Olivebioteq 2011. Chania, Greece,Vol.1, pp.269-274, 2012.

Anthracnose in Olives Article - Symptoms, Disease Cycles & Management

 

For further information on Dr Vera Serveeva work visit: http://olivediseases.com

 

New IPDM Project:

A new three-year research project is now underway to equip growers with a stronger understanding of the three major olive pests and diseases and the skillset to sustainably manage them. Led by Associate Professor Robert Spooner-Hart from Western Sydney University (WSU), the project OL17001  An integrated pest and disease management (IPDM) extension program for the olive industry will provide growers and the supply chain with appropriate IPDM extension services focused on Black Scale, Olive Lace Bug and Anthracnose.

This project has been funded by Hort Innovation, using the olive research and development levy and contributions from the Australian Government. Hort Innovation is the grower owned, not-for-profit research and development corporation for Australian horticulture.

Key issues being addressed through the project include:

  • Understanding the importance of timing for chemical or biological interventions for effective, economic pest and disease management
  • Ability to identify the key pests/diseases, their symptoms, especially at an early stage, as well as any natural enemies
  • Better understanding of the life cycles of the three key pests/diseases and the factors conducive to infestations, including weather, plant health and grove management practices, to enable better decision making.