Document Type : Original research articles
Authors
1
Agric. Zool. Dept., Fac. Agric. Cairo University, Giza, Egypt
2
Plant Protect. Res. Inst., Agri. Res. Center, Dokki, Giza, Egypt
Abstract
Two levels of Steatoda triangulosa (25 and 50 individuals/ replicate) were released (one time); on 29th September 2005 at rate 50 individuals and on 20th April 2006 at a rate 25 individuals. For the first level of release, the pre-count in the releasing area with T. urticae was 12.1 individuals / leaf; while it was 12.9 individuals / leaf in (check). The number of T. urticae in the 1st release/ plot decreased gradually from 12.1 on 29th September to 8.03, 5.9, 5.03, 6.36 and 5.8 individuals / leaf on 6, 13, 20, 27 October and 3 November, respectively. T. urticae populations per check plot changed from 12.9 individuals / leaf on 29th September to 15.0, 22.9, 25.1, 31.6 and 54.7 individuals / leaf in the same dates, respectively. Percent reduction of T. urticae in 1st release plot increased gradually to reach 20, 65, 62, 62 and 80% on the previously mentioned days of October and November, respectively. For the second level of release, the pre-count in the releasing area with T. urticae was 7.7 individuals / leaf; while it was 6.7 individuals / leaf in (check). The number of T. urticae in the 1st release plot decreased gradually from 7.7 on 20th April to 6.4, 3.9, 3.4, 1.4 and 0.6 individuals / leaf on 30 May, the 10th, 20th, 30th June and 10th July, respectively. Compared to check plot, T. urticae populations changed from 6.7 individuals / leaf on 20th April to 11.3, 11.2, 18.9, 25.7 and 30.2 individuals / leaf on the same dates, respectively. In addition, the percent reduction of T. urticae increased gradually to reach 51.0, 69.0, 85.0, 95.0 and 81.0%, respectively.
Keywords
)
View on SCiNiTO