Baraa’a Hawis(1) (2)*, Ziad Chikh-Khamis(2) and Monir Alnabhan(3)
(1) Directorate of Agriculture, Ministry of Agriculture and Agrarian Reform, Hama, Syria.
(2) Department of Plant Protection, Faculty of Agriculture, Alba’ath University, Homs, Syria.
(3) Center of Scientific Agriculture Research, GCSAR,Hama, Syria.
(*Corresponding author: Baraa Hawis. E-Mail: firstname.lastname@example.org).
Received: 8/06/2021 Accepted: 23/08/2021
Effect of augmentative releasing of the lacewing,Chrysoperla carnea (Steph.), on the density of the predator and the populations of its prey in the cotton field was studied in 2017 in Hama using three treatments: (T1l) releasing the predator by 1000 larvae (at 2ndinstar), per 1000m² once a season;(T2l) releasing the predator by 500 larvae per 1000m²twice a season at one-month interval;(Te) releasing eggs of the predator at 1000 eggs per 1000m²once a season; and (C) the control field without any release. The predator releasing reduced the numbers of whitefly nymphs Bemisia tabaci in the three trea tments,The releases in treatments (T1l andTe) reduced the numbers of whitefly nymphs one week after the release by 84% and 89.31%respectively. However, aweek after the second release in T2l, the reduction rate became 76.9 and the differences between the three treatment were not significant. The treatments reduced the aphid Aphis gossypii population densities compared with the control. The largest reduction rate was one week after predator release in T1l, followed by Te 89.07%, 73.46% respectively. While one week after the second release, the reduction rate in T2l was higher than T1l and Te (significantly) by a reduction rate 57.55% . Then, the reduction rates in the three treatments increased gradually until the end of the season. The densities of the C. carnea eggs laid by endemic predators naturally in the treatment blocks decreased throughout the season after releasing of the predator compared with the control. There was a significant linear correlation between the endemic predator egg densities and their prey population densities (whitefly and aphid) in the cotton field.
Keywords: Cotton, Augmentative releasing, Chrysoperla carnea, Bemisia tabaci, Aphis gossypii.
Full paper in Arabic: pdf