No abstract

Population densities of wheat ear insects infesting different winter wheat varieties (n = 50) were estimated during 2008 and 2009 seasons near Halle, central Germany. The research was aimed at identifying wheat varieties most resistant to wheat ear insect pests. Two methods were used to evaluate the degree of insect infestations in different wheat ear varieties. Wheat ears were dissected when kernels were in Zadoks stage 73 and examined using a binocular microscope to count the number of spikelets and infested kernels, and to identify the insect pests present. In addition, white water traps were placed on the soil underneath each variety to collect mature larvae of wheat blossom midges (WBMs) as an indicator of potential crop risk for the next year. There were significant differences in the number of thrips and WBM infesting wheat ears among varieties in both years. Thrips numbers were the highest in Akratos, Limes and Ritmo varieties in 2008 and in Michigan Amber, Elegant and Kontrast in 2009. Thrips were the lowest in Thuareg in 2008 and Robigus varieties in 2009. The results showed that the highest WBM infestation level was observed in Michigan Amber in both years. The lowest WBM infestations were found in Türkis, Cubus, Capo, Welford and Robigus in both years. The number of infested kernels was positively correlated with WBM among varieties. In the water traps, the highest numbers of WBM larvae were recorded in Saladin and Bussard in 2008 and Orlando, Julius and Glasgow varieties in 2009. The lowest values were recorded in Victo, Enorm, Robigus and Welford varieties in both years. The results provide a guide for selecting winter wheat varieties with resistance to these wheat ear pests.

Orange wheat blossom midge damage can impart serious loss of quantity and quality of winter wheat. Wheat midges were evaluated in large scale field in winter wheat in bad lausick (leipzig, Saxsony) central germany. the present study aimed at studying the activity of wheat blossom midges WbM, Sitodiplosis mosellana (géhin) and Contarinia tritici (Kirby) using pheromone, sticky traps and two types of water traps. Management of midges with different treatments was studied; Karate (pyrethroid), biscaya (neonicotinoid) and neemazal t/S (botanical insecticide) were sprayed on wheat at heading stage (gS 55). Monitoring was conducted before the treatment and continued for 4 weeks after the treatment. Pheromone traps were used for forecasting midge adult population and determine the control date. Water traps were used to assess midge larvae, while midge adults were surveyed using sticky traps. a strong correlation between midge catches and weather conditions was obtained; as well a coincidence between pheromone catches and wheat midge infestation in the susceptible growth stages (gS 47-65) was recorded. insecticide applications to fields of midge-infested winter wheat significantly reduced the wheat midge damage. There were significant differences in wheat midge numbers between treated and untreated; wheat midge numbers were lower in the treated than in control. the results proved that both Karate and biscaya caused more mortality to wheat midges than neemazal t/S. Zur Bekämpfung von Weizengallmücken in Winterweizen in MitteldeutschlandZusammenfassung Weizengallmücken sind ökonomisch bedeutsame Schädlinge im Winterweizen und können in abhängigkeit vom befallsbeginn in der Weizenähre verschiedene Schadsymptome (z. b. Kümmerkörner) verursachen. Zur etablierung einer bekämpfungsstrategie wurde im Jahre 2012 in der Leipziger Tieflandsbucht ein Insektizidversuch auf einem Praxisschlag durchgeführt. Die Zielstellung des sogenannten "On-Farm-experiment" war es, eine bewertung direkt im Produktionsfeld vorzunehmen und Hinweise zur entscheidungsunterstützung der landwirte zu formulieren. Der methodische ansatz berücksichtigte den einsatz von Pheromonfallen, gelbtafeln und Wasserschalen zur Überwachung der Flugaktivität der Mücken und zur erfassung des abwanderungsverhaltens der larven. Die bekämp-fungsstrategie orientierte sich am derzeitigen Wissensstand und terminierte einen Spritztermin zum Ährenschieben. es wurden zugelassene insektizide hinsichtlich ihrer effektivität gegenüber Weizengallmücken in einem Zeitfenster von fünf Wochen getestet. Die ergebnisse 2012 zeigen eine gute Korrelation zwischen Mückenaktivität und den Wetterbedingungen. Die Pheromonfallenfänge signalisieren unter den Feldbedingungen eine enge Koinzidenz zwischen dem Flughöhepunkt und dem kritischen Pflanzenstadium (BBCH 55-65). Der bekämpfungstermin war somit optimal auf die Schädlingsaktivität abgestimmt. Die Feldstudie belegt signiGesunde Pflanzen (2013) 65:7-13