Evaluation of the effectiveness of different fungicides and determination of the best spraying times in the control of olive peacock spot disease in the Tarom region of Zanjan province

Olive peacock spot disease caused by Venturia oleaginea is the most important fungal disease of olive trees worldwide, which in areas with high levels of infection the use of fungicides for disease control is inevitable. This study was conducted to evaluate the effectiveness of several different fungicides and to determine the best spraying times for chemical control of the disease in the Tarom region of Zanjan province during two years. In the first year, the efficacy of three known strobilurin group of fungicides (Stroby®, Flint® and Nativo®) in comparison with three copper fungicides (Bordofix®, Mishocap® and Nordox®) in three-time treatments on November 6, March 6 and April 6 in factorial experiment was examined. In the second year, the effectiveness of four fungicides of Nativo, Thiophanate Methyl, Mancozeb® and Nordox with four spraying times on November 6, December 6, March 6 and April 6 was evaluated in a randomized complete block design. The results of this study showed that the studied strobilurin group of fungicides provided the necessary efficiency in control the damage of peacock spot disease in severe infection conditions. In contrast, copper fungicides did not have promising results. Nativo fungicide had the best performance in controlling the disease in the first year with 61% and in the second year with 63% reduction in the incidence of the disease compared to the control. November spraying had the maximum effect and April spraying had the least effect in reducing the damage of the disease. However, at least three sprays are required for acceptable control of the disease.