Population dynamics of Myzus persicae (Sulzer) and its associated natural enemies in spring potato crop, Peshawar-Pakistan

This study was conducted to determine the population dynamics of Myzus persicae (Sulzer) and its associated natural enemies, Coccinella septempunctata (L); Episyrphus balteatus (de Geer); Chrysoperla carnea (Stephens); and Aphidius matricariae Haliday and percent parasitism of the aphid in the spring potato crop at Peshawar, during 2006. The host plant was cultivar Kuroda of potato. The results showed that M. persicae was consistently at different densities in different times on potato throughout the growing season. The aphid was first recorded during the last week of February 2006 with a mean density of 0.61 aphids / leaf. The number of aphids steadily increased with significant differences till the 3rd observation (2nd week of March, 2006), where 3.42 aphid / leaf were recorded. During 3rd week of March a peak aphid density of 4.22 aphid/ leaf was recorded. After words that the aphid decreased till the last observation where 1.43 aphids/leaf was recorded. The period from 2nd week of March to 3rd week of March was found very critical and need special attention for the effective and timely management of the aphid. In the natural enemies of M. persicae, the predominant species C. septempunctata, E. balteatus, C. carnea, A. matricariae and percent parasitism was first recorded during 4th week of February 2006. The population density of all of the natural enemies along with percent parasitism rate was gradually increased and the highest population was recorded on the 3rd week of March, where mean number of 22.8 C. septempunctata, 6.5 E. balteatus, 13.0 C. carnea, 10.0 A. matricariae (no of mummies) per potato plant and 41.4% percent parasitism was recorded. After that, as the population of M. persicae started decline, the same trend was followed by all of its natural enemies. Lowest population was recorded for the natural enemies as well as for the percent parasitism on the last observation (last week of April 2006).