stablishment and parasitiEsm efficiency of Trichogramma principium (Sugonyaev et Sorokina) on Helicoverpa armigera (Hb.) infesting cotton in Sudan

Tag Elsir E. Abdalla, Ahmed M. Mustafa, Hassan A. Mubarak

Abstract


This study was conducted at the Gezira Research Station (GRS) farm during 2010/11 season to verify establishment and parasitism efficiency of Trichogramma principium (Sugonyaev et Sorokina) (Hymenoptera: Trichogrammatidae) in eggs of Helicoverpa armigera (Hb.) (Lepidoptera: Noctuidae) infesting the Sudanese cotton cultivars "Barac 67B", "Hamid", "Burhan" and "Abdin". Trichogramma was acquired from the Rearing Unit, Agricultural Research Corporation (ARC), at preimaginal (prepupal) stage, in eggs of the rice moth Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae). Depending on numbers of H. armigera eggs / 100 plants, one release was done on each of Barac and Hamid and two on each of Abdin and Burhan. The release rate was 24,000 parasitoids /fed, at 7x7m distance between release points and 14-day intervals. Evaluation was done between treated plots with Trichogramma versus untreated. Observations consisted of the percentage of emerged parasitoids, percentage of parasitism and the numbers of the African bollworm larvae /100 plants. At the first release, the percentage of emerged parasitoids ranged between 71% in Barac and 86.4% in Hamid; the cultivars` average ranged between 60.5% and 94.8% and the overall average was 79.2%. The percentage of parasitized H. armigera eggs ranged between 22.2% and 60%. At the second release, the percentage of emerged adults ranged between 73.2% in Burhan and 82.1% in Abdin; the cultivars average

ranged between 46.6 and 96.7% and the overall average was 77.7%. The percentage of parasitized H. armigera eggs ranged between 22.2% and 77.7%. The high level of parasitoid emergence declared a good viability of the released material, tolerance of the parasitoid to the local weather

 

 

 

 

 

 

conditions and acceptance of the crop. The levels of parasitism reported were quite acceptable for this introductory release and first occurrence of the parasitoid in this new cotton agroecosysytem. A positive signal of migration from treated to untreated plots was observed through parasitized H. armigera eggs detected in the latter plots. The numbers of H. armigera larvae were negligible in both treatments. Accordingly, for proving potential capacity of establishment and parasitism efficiency against H. armigera, T. principium is strongly recommended for use on Sudanese cotton cultivars.


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