The Control and Ecological Effect of Coccinella septempunctata on Myzus persicae in Liangshan Tobacco Field
- Received Date: 09/02/2022
-
Key words:
- tobacco /
- myzus persicae /
- coccinella septempunctata /
- control efficiency
Abstract: In order to reveal the control and ecological effect of Coccinella septempunctata on tobacco aphids, the population and quantity of pests and natural enemies in tobacco fields were investigated. The results showed that the release of C. septempunctata had a certain effect on control of tobacco aphids. The corrected mortality rate reached 62.88% on the first day after release, and gradually decreased to 50.77% and 39.43% on the second day and third day, respectively. The results of diffusing behavior observation showed that the adult C. septempunctata had strong dispersal ability. The colonization rate of C. septempunctata in the target tobacco plant was 50.00% at 1 st day after release, and 0 at the 2 nd and 3 rd day after release. The population dynamics of all kinds of pests and natural enemies before and after the release were preliminarily determined. The number of wingless aphids per plant was the highest among all the pests with average 15.06 aphids per plant, followed by the winged aphids with average 1.67 aphids per plant. The main natural enemies were Aphidius gifuensis Ashmead and Syrphidae. The number of pests and natural enemies showed a trend of decreasing first and then increasing gradually. The decrease of wingless tobacco aphid, tobacco aphid cocoon bee adult and stiff aphid was obvious on the first day of investigation, and the average number of wingless tobacco aphids per plant decreased to 7.05 heads per plant.