Using of Chrysoperla carnea in Combination with Trichogramma Species
for Controlling Helicoverpa armigera

• Nabil El-Wakeil(1) And Stefan Vidal(2)
• (1) Pests & Plant Protection Dept., National Research Centre, El-Tharir str. Dokki, Cairo, Egypt
• (2) Institute of Plant Pathology & Protection, Goettingen University, Goettingen, Germany
• The Third International Conference onIPM Role in Integrated Crop management and Impacts on Environment and Agricultural Products. 26-29 November 2005, Giza, Egypt.

Abstract

One new approach in biological control of Helicoverpa armigera (Hüb) in organic cotton farms is the combined use of parasitoids and predators. The combination between parasitism of Trichogramma species and predation of Chrysoperla carnea (Stephen) on H. armigera was investigated in the laboratory and greenhouse. In the laboratory, the effect of preying time of Chrysoperla combined with Trichogramma on predation of H. armigera eggs for 1, 12 and 24 hours was studied. Moreover, effects of Chrysoperla predation on parasitized eggs by Trichogramma species after 2-3, 5-6 and 7-8 days were investigated. In the greenhouse, combined releases of Trichogramma and Chrysoperla were studied to control Helicoverpa on two cotton cultivars. Preying time of Chrysoperla affected both predation and parasitism rates. Predation rates increased with increasing preying time of Chrysoperla. Predation rates of Chrysoperla on parasitized Helicoverpa or Sitotroga eggs decreased with aging of parasitized eggs. In the laboratory, the proportion of H. armigera eggs parasitized when both natural enemies were present differed significantly between Trichogramma species, being higher in T. pretiosum (Riley) compared to T. minutum (Riley). On the other hand, the proportion of H. armigera eggs preyed in greenhouse cages was higher in T. minutum compared to T. pretiosum. Combining Trichogramma species and C. carnea for controlling H. armigera eggs resulted in higher mortality rates than Trichogramma alone. Predation and parasitism rates were affected by different cotton cultivars; they were higher on Giza 89 than on Giza 86. The combination between parasitoids and predators could be a one approach in IPM programs of H. armigera in organic cotton farms.