The effect of biological periods and number of individuals on the damage amount of Leptinotarsa decemlineata Say (Coleopteta: Chrysomelidae)

Abstract

In this study, the relationships between the amount of damage and the phenology of the potato plant, and biological periods and the number of individuals of Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) were investigated. For the relationship between the different biological stages of the insect and the amount of damage, individuals were allowed to be fed for 24 hours. The most fed in biological period on the potato plant was the third larval stage of L. decemlineata while the least period was recorded as adult individuals. For the relationship between the phenological period of the plant and the amount of damage, potato plants with a length of about 20 and 40 cm were used. Adult individuals of L. decemlineata averaged 0.46 g in leafy branch pieces of a 20 cm potato plant, and 0.36 g on average in 20 cm leafy branch pieces from the tip of a 40 cm potato plant. It was determined that adult individuals of L. decemlineata feed more on leaves of young potato plant. For the relationship between the number of individuals and the amount of damage, experiments were set up with adults in groups of 1, 2, 3, 4 and 5, respectively. While a single adult individual of L. decemlineata cause an average of 0.15 g feeding damage on the leafy branch parts of the potato plant, it was recorded as 0.13 g for two individuals, 0.24 g for three individuals, 0.21 g for four individuals, and 0.33 g for five individuals, respectively.