Prey preference and consumption by two polyphagous predatorsTyphiodromus pyri Scheuten (Acari: Phytoseiidae) and Chrysoperla carnea(Stephens) (Neuroptera: Chrysophidae) of different mite pest species ofapple orchards

The predatory mite, Typhlodromus pyri Scheuten and green lacewing,Chrysoperla carnea (Stephens) have been reported as the most importantnatural enemies of mites viz., Panonychus ulmi (Koch), Tetranychus urticaeKoch (Acari, Tetranychidae) and Aculus schlechtendali Nalepa (Acari,Eriophyridae) in apple orchards in central and western Europe. Thepresent experiments on prey preference of the two predators from thethree pest mite species were carried out in 2002 at The Department ofEntomology and Plant Protection, Institute of Phytopathology, TheUniversity of Bonn, Germany. The results showed that T. pyri nymphs aswell as adults consumed daily a significantly higher mean number of allstages of A. schlechtendali than P. ulmi or T. urticae. It preferred allstages of P. ulmi to T. urticae also. The nymphs consumed daily 45.2 eggsof A. schlechtendali, 28.7 of P. ulmi or 22.3 of T. urticae, while 35.9, 6.5 or5.2 nymphs of the three species, respectively, when offered separately.Similarly, the number of adults of prey species daily consumed were 27.2(A. schlechtendali), 4.8 (P. ulmi) or 2.5 (T. urticae). T. pyri adults similarlyconsumed a higher number of 65.7 eggs of A. schlechtendali as compared to40.3 of P. ulmi or 32.3 of T. urticae when offered separately. The adultsconsumed 57.7 nymphs of A. schlechtendali, 10.1 of P. ulmi or 8.7 of T.urticae, and 37.2, 6.5 and 4.3 adults/day of the three species, respectively,when offered separately. The larvae of C. carnea similar to T. pyri nymphsand adults daily consumed a significantly higher mean number of all stagesof A. schlechtendali than the other species when offered both separatelyand together. When offered separately, it consumed 2517.3 eggs of A.schlechtendali, 1480.2 of P. ulmi, 1350.5 of T. urticae or 47.5 of T. pyri. Thelarvae consumed a mean daily number of 1830.2 nymphs of A.schlechtendali, 870.5 of P. ulmi, 810.3 of T urticae or 25.2 of T. pyri.Similarly, the larvae consumed a higher mean daily number of 1520.7 adultsof A. schlechtendali as compared to 130.2 of P. ulmi, 90.5 of T. urticae or42.7 of T. pyri when offered separately.