Effect of different potato cultivars on nutritional indices and activity of some digestive enzymes of Leptinotarsa decemlineata (Col.: Chrysomelidae)

Nutritional indices and digestive enzymatic activity of Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) was studied on eight potato cultivars including Agria, Dayfla, Ceasar, Labadia, Lady Rozeta, Lotta, Marfona, and Santae under laboratory conditions (25±1 °C, 65±5% R.H. and a photoperiod of 16L:8D h). L. decemlineata third instar larvae reared on cultivar Ceasar had the lowest values of consumed food and larval weight gain. Approximate digestibility values were highest and lowest on cultivars Agria and Marfona, respectively. The larvae reared on cultivar Santae showed the highest efficiency of conversion of digested food and efficiency of conversion of ingested food. Those larvae that fed on cultivar Agria had the highest relative consumption rate. In contrast, the larvae fed on Labadia and Ceasar cultivars had the lowest relative consumption rate. Furthermore, the larvae fed on Santae and Agria cultivars had the highest relative growth rate. Amylolytic activity in the 4th instar larvae was the lowest on Ceasar and Labadia and the highest activity was observed in the larvae fed on cultivars Lotta and Santae. The highest larval proteolytic activity was recorded in Agria, Santae and Lotta cultivars. According to the results, Labadia and Ceasar were the most unsuitable cultivars for feeding of L. decemlineata.