Peacock Spot of Olive: A Serious Threat to Olive Growing

Peacock spot, also known as olive leaf spot, is one of the most important diseases of the olive, with serious effects on productivity and olive-oil quality. The fungus Venturia oleaginea, which causes the disease, affects olive tree leaves, producing brown spots that lead to premature leaf drop. Understanding the environmental factors and the fungus's biology is critical for effective management and prevention.

Environmental conditions that favour spread

The fungus V. oleaginea thrives under specific temperature and humidity conditions. Recent studies show that:

Current climatic conditions — temperatures around 20°C and frequent rainfall — are ideal for the disease to develop.

Disease severity and infection range

Peacock-spot infection can occur at temperatures from 5°C to 25°C. However, disease severity is highest at 20°C when leaves remain wet for 12–24 hours. Increasing the temperature to 25°C reduces severity.

The minimum wetness duration for infection varies with temperature:

This shows that the relationship between temperature and wetness is decisive for the disease's development.

Forecasting models for peacock spot

Effective management of peacock spot relies on predicting infection conditions. Several forecasting models have been developed to help growers take timely action.

Each model has advantages and disadvantages, and the choice depends on the farm's needs and the data available.

Management and prevention

To protect olive trees from peacock spot, growers can apply the following:

Conclusion

Peacock spot remains a serious threat to olive growing, but progress in understanding environmental parameters and the use of forecasting models offer powerful management tools. By leveraging modern knowledge and technologies, growers can protect their crops and secure both the quality and quantity of their production.