Research on biological control and important as weed milk thistle [Silybum marianum (L.) Gaertner] in the Çukurova Region

This study was conducted to determine the life cycle of milk thistle [Silybum marianum (L.) Gaertner] which is problemic in wheat field and pasture in the Çukurova Region from November 2006 to May 2011 towards its possible biological control. The permanent plots were performed in Çatalan, Karataş and İmamoğlu locations that had different ecological conditions. The cotyledon, seedling, rosette and mature stages of milk thistle were recorded in the plots in two week intervals. A plant was chosen in each plot to determine plant heights, root diameters, number of capitulas, diameters of capitulas, number of seeds in capitulas and total number of seeds . The average of the milk thistle number was determined as 18.17 plants/m2 in the Çukurova Region The average plant height was found to be 117,16 cm where the average plant diameter was 1,68 cm. The average number of capitulas was determined as 7,66 and the average diameter of capitula was 2,83 cm. The average seeds per capitula was 65,63 which means 533,14 seeds per plants. Finally, the average seed bank of soil was determined as 1577,61 seeds/m2 in September and 5764,92 seeds/m2 in autumn. The main insects affecting the capitula seeds were found as Larinus latus Herbst (Col: Curculionidae) and Rhinocyllus conicus Froelich. (Col: Curculionidae) and are having a good potential for the biological control of milk thistle.