Efficiency of Certain Bio-Insecticides for Reducing the Yield Losses due to the Bean Pod Borer, Etiella zinckenella (Treitschke) in Soybean Fields

The pod borer Etiella zinckenella (Treitschke) is most destructive insect which infest crops of leguminosae in Egypt. Field experiments were carried out in farm of Agricultural Research Center, Giza governorate during 2017 and 2018 seasons. First experiment was conducted to study seasonal incidence of this insect on soybean and its relation with weather factors under natural conditions. In first season, the larval population increased to make two peaks, that recorded in the 1st and 3rd weeks of September. In second season found one peak on September, 4th. The relationship between population fluctuation and three climatic factors (minimum and maximum temperatures& R.H. %) were studied. Simple correlation of Max. and Min. temperatures were negative but R.H.% gave positive effects. The second experiment was conducted to evaluate efficacy of Biover, MgChl and Dipel 2xfor control of this insect under field conditions in addition the yield. Results showed that, mean reduction of larvae for highest concentrations of tested treatments were arranged descendingly as Biover (63.04%) followed by MgChl (55.52%) and finally Dipel 2x (51.28%) with significant differences between treatments compared with control. Also, depending on highest concentration, Biover was the superior in this respect being registered 45.71% increasing in the yield over the control value followed by MgChl (42.39 %) and Dipel 2x (36.19%). Maximum net return was obtained from Biover (4g/L) (4262.92 /fed.) followed by Biover (2g/L) (4172.92/fed.) and Diple 2x (4g/L) (3749.59/fed.). Biover and MgChl gave highest reduction in population of this insect and best seed yield.