Parasitism Efficiency of Encarsia Lutea Masi on Bemisia tabaci (Genn.) and its Interaction with Insecticides Applied on Cotton Crop in New Halfa Agricultural Scheme (Sudan

The study was conducted at the commercial field of New Halfa Agricultural Scheme (NHAS), during 2001/02 and 2002/03 seasons, to determine the parasitism efficiency of Encarsia lutea Masi (Hymenoptera: Aphelinidae) on Bemisia tabaci (Genn.) (Homoptera: Aleyrodidae), and its interaction with the insecticidal treatments carried against the insect pests of cotton. The parasitoid, microscopically determined inside the whitefly nymphs, started to appear in both seasons since early November and increased towards the end of the season. Parasitism showed density dependence with the whitefly adult numbers leaf, In the first season, the highest level of parasitism was 45.4%. average for November was 23.2%, December 40.3% and for the season was 27.5%. In the second season, the highest level of parasitism reached was 48.2%, the average for November was 9.3%, December and the season's average was 27.2%. E. lutea delayed the insecticidal applications against the whiteflies during November in both seasons and kept them low during December so that no insecticidal interference was needed. The parasitoid secured saving of 29% of the sprays that should have been applied in the first season, and 50% in the second season. This was roughly estimated as three million US dollars directly saved resources in both seasons, besides the indirect benefit of improving the grade of the cotton fibre, due to reduction of the immature stages of the whiteflies. Four insecticide mixtures, of the 12 applied in the two seasons, reduced parasitism by 3%-45%. The rest did not interfere with the incidence of parasitism. &nbsp

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

      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.   المقدرة على الاستيطان والكفاءة التطفلية ل  Trichogramma principium (Sugonyaev et Sorokina)  ضد Helicoverpa armigera (Hb.)   على القطن في السودان      أجريت هذه الدراسة بمزرعة محطة بحوث الجزيرة في موسم 2010-2011 للتثبت من المقدرة على  الاستيطان و الكفاءة التطفلية ل  Trichogramma principium (Sugonyaev et Sorokina) (Hymenoptera: Trichogrammatidae) على بيض دودة اللوز الأفريقية Helicoverpa armigera (Hb.) (Lepidoptera: Noctuidae) على أصناف الأقطان السودانية "باراك B 67"، "حامد"، "برهان"، و"عابدين". تم الحصول على طفيل التريخوجراما من وحدة الإكثار بهيئة البحوث الزراعية في طور ماقبل التشرنق بداخل بيض فراشة الأرز  Corcyra cephalonica (Lepidoptera: Pyralidae) . اعتمادا على عدد بيض دودة اللوز / 100 نبات، فلقد أجريت إطلاقه واحدة على كل من الصنفين باراك و حامد و اطلاقتان على كل من الصنفين عابدين و برهان بمعدل 24000 طفيل للفدان و على مسافات 7x7م بين نقاط الإطلاق و بفاصل 14 يوما بين الإطلاقات. تمت المقارنة بين الحقل المعامل بالتريخوجراما و الغير معامل. اشتمل التقييم على تحديد النسبة المئوية لبزوغ الأطوار المكتملة من الطفيل، النسبة المئوية للتطفل و عدد اليرقات في ال 100 نبات. عند الإطلاقة الأولى،  تراوحت النسبة المئوية لبزوغ الأطوار المكتملة بين 71% كما في باراك و 86.4% كما في حامد، و المتوسط  للأصناف بين 60.5% و 94.8% و المتوسط العام لهم 79.2 % و تراوحت النسبة المئوية للتطفل بين 60% و 22.2%. عند الإطلاقة الثانية،  تراوحت النسبة المئوية لبزوغ الأطوار المكتملة بين 73.2%% كما في برهان و 82.1% كما في عابدين، و المتوسط للأصناف بين 46.6%  و 96.7% و المتوسط العام لهم 77.7% ، و تراوحت النسبة المئوية للتطفل بين 77.7% و 22.2%. يدل هذا المستوى العالي من بزوغ الأطوار المكتملة على الحيوية الجيدة للطفيل المطلق، تحمله للظروف الجويه وتقبله للمحصول العائل.  تعتبر المستويات المتحصل عليها من التطفل مناسبة لهذا الإطلاق الإستهلالى و تواجد الطفيل لأول مرة على  هذا الوسط البيئي الزراعي الجديد للقطن بالسودان. هنالك مؤشرات لبداية هجرة الطفيل من المساحات المعامله لغير المعاملة تمثل في تواجد بيض متطفل علية في الأخيرة. كان عدد يرقات ديدان اللوز قليلا في المعاملتين. و عليه، و لقابليته على الاستيطان و كفاءته التطفلية المقبولة على ديدان اللوز الأفريقية فان ال T. Principium موصى باستعماله بشدة على أصناف الأقطان السودانية.      &nbsp

Effects of application methods and dose rates of carbofuranon the control of maize infesting stemborers and consequences on agronomic, yield and yield parameters in central Sudan

This study was conducted at Gezira (GRS) and Sennar Research Stations (SRS) farms during 2014/2015 winter season. Carbofuran was tested in form of "Carbodan 10 G®". The application methods were: Soil dressing method (SDM) applied with the seeds at sowing, top dressing method (TDM) applied into whorls after emergence, and broadcasting method (BM) applied after emergence. The doses were 0.225, 0.3 and 0.375g /hole in SDM and 5.85, 7.8 and 9.75kg/fed in each of TDM and BM. Untreated control (UC) was included in the test. Stemborers damage was assessed on maize leaves and stems. Agronomic, yield and yield parameters were timely recorded. Residue analysis was performed in grains taken at milky and maturity stages. The ordered SDM, TDM and BM showed decreasing trend of dead heart by scoring 6.1%, 5.7%, and 5.5% at GRS, and 7.3%, 4.6% and 3.1% at SRS, respectively, but didn’t differ much by effects on leaves. An increasing trend in number of cobs /fed was also evident. All carbofuran treatments reduced percentage of infested plants to a range of 12.6%-16.8% vs. 22.4% in the UC at GRS, and 5.2%-15.5% vs. 30.5% in the UC at SRS. SDM at 0.375g/hole, TDM at 7.8 kg /fed and BM at 9.75 kg /fed recorded significantly lower percentage of dead heart, 3.7%, 3.8% and 3.6%, vs. 14.0% in the UC at GRS, and 9.3%, 2.4% and 4.5% vs. 20.1% in the UC at SRS, respectively. They increased plant stand, plant height, number of cobs /fed, 1000-grain weight and grain yield by 32%-105% over the UC at GRS and 46%-175% at SRS. TDM at 7.8 kg /fed produced 2.2 ton /fed which was about three times as much vs. UC (0.8 ton /fed) at SRS (P≤0.05). No residue of carbofuran and its metabolites were detected in all grain samples