Population fluctuation of aphids, Lipaphis erysimi (Kalt) with response of biological control under mustard field conditions

Abstract

The field experiment was carried out in the experimental area of Shah Abdul Latif University, Khairpur during Rabi season, 2014-15 on six cultivated mustard varieties viz., S-9, Toria selection, Aghati sarhein, J.S -13, Janbho selection and Sindh raya. The results indicated that sucking insect pest; Lipaphis erysimi (Kalt) appeared from seedling till harvest of the crop. The overall means showed that the maximum population was recorded on T. selection, 28.92 per leaf followed by A. sarhein, 22.45; J.S-13, 13.71; S.9, 13.31; S. raya, 11.55 and J. selection, 10.52. The analysis of variance showed significant differences in the population of pest in all varieties. The predators’ activities were recorded on the varieties having maximum pest activities. Overall data suggested that the population of insect pest and predators remained constant on all varieties. Finally, the less population of the predators was due to less population of aphids. Similarly the predator population was also observed on same 6 varieties of mustard crop namely; S-9, T. selection, A. sarhein, J.S-13, J. selection and S. raya. The overall means showed that the maximum population of C. septempunctata recorded on A. sarhein, 1.36 per plant followed by T. selection, 1.14; S-9, 0.69; J.S- 13, 0.65; S. raya, 0.63, and J. selection, 0.38, respectively. It was concluded that in starting the predator population was found lesser but when it went in to peak levels the pest aphid population reduced which found to be positive correlation with pest population.