Infestation rates of Bactrocera oleae (Dip.: Tephritidae) in 22 olive cultivars at Tarom Olive Research Station of Zanjan province, Iran

Olive fruit fly, Bactrocera oleae (Rossi), is one of the most injurious pests of the olive in Iran. Since its introduction to Iran, in 2004, it has caused considerable economic loss to the domestic olive industry, especially in the years when the climate is favorable to its activity. In this research, we evaluated the infestation rates of olive fruit fly in 22 imported and native olive cultivars at Tarom Olive Research Station, Zanjan, Iran, from 2005 through 2009. The first sampling was started at hard pitting time and continued until harvesting time in which 20-50 fruits were collected from each tree (replicate). Totally 60-150 fruits, from 3 replications, were carefully examined under stereomicroscope in the laboratory. Using the formula of Sqrt (x + 0.5), the data were transformed and subjected to analysis based on Randomized Complete Block Designs usingsoftware SAS, 9.0. The results revealed that among the four recommended cultivars for the region, the cultivar "Arbequina" showed the lowest rate of infestation, while "Konservolia"," Zard", and "Koroneiki" were the most susceptible cultivars due to their higher rates of infestation in 2005 (11.62%, 13.74% and 7.56%), 2007 (3.23%, 1.01% and 1.49%) and 2009 (10.03%, 34.75% and 15.10%), respectively. The cultivars "Lechin de sevilla" and "Manzanilla cacereña" were found to be unfavorable to olive fruit fly.