DEVELOPMENT OF A SPRAY AND ATOMIZER TECHNIQUE FOR APPLYING EGGS OF CHRYSOPERLA-CARNEA (STEPHENS) IN THE FIELD FOR BIOLOGICAL-CONTROL OF APHIDS

In the present paper, the suitability of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) eggs for mechanical application was studied and spray techniques for applying the eggs without stalks in water su spension were development for biological aphid control in the field. W ater was used as a suitable carrier agent in which the eggs could rema in up to 12 h without adverse effects on the hatching rate. The C. car nea eggs could withstand a liquid pressure up to 4.5 bar without adver se effect which is important for the determination of the possible way of atomizing. The use of deflector jets with inner diameters of more than 0,84 mm and the use of the nozzle FloodJet TK 1.5 (Spraying syste ms Company, Remshalden) with spraying pressures of even up to 3 bar al lows the application of intact Chrysoperla eggs. In low volume sprayin g, the tested pneumatic nozzles with diameters of 1.0 to 2.0 mm (Schut ze Company, Bremen), which atomize liquids through compressed air, did not reduce the larvae hatching rate. Even with an air pressure of up to 2 bar, the eggs were not damaged. The addition of several substance s, Adhasit (Spiess Company, Kleinkarlbach), Citowett (BASF Company, Lu dwigshafen), and UHU (UHU Company, Buhl) to the water to increase the adherence of the eggs did not result in any negative effect on C. carn ea at the concentrations tested. The field experiments showed that the developed spray and atomizer techniques allowed a targeted deposition of intact C. carnea eggs on sugar beer plants. With the spray techniq ue, a mean of 5.4 eggs and with the atomizer technique, a mean of 7.0 eggs were found per plant after the application, in comparison to a de fined optimum value of 11 eggs per plant.