Functional diversity in apple orchards, effect on codling moth and its natural enemies

Ecological infrastructures such as flower strips can improve conditions for natural enemies in apple orchards and may thus reduce pest infestation. The present study assessed the density of overwintering codling moth Cydia pomonella L. (Lepidoptera, Tortricidae), level of parasitism, infestation by entomopathogenic fungi and other mortality factors in ten organic orchards -five orchards with flower strips and five orchards without flower strips. In orchards with flower strips, predation on sentinel eggs was assessed in different distances from the strips. No clear difference was found between infestation levels in organic orchards with and without flower strips. High variability between individual orchards may explain this. Within orchards with flower strips mortality of codling moth larvae collected near flower strips was higher than for larvae collected further away from strips. Likewise mortality of sentinel eggs was higher in trees near the flower strip than further way. Within orchards with flower strips, there was increased predation activity and increased mortality of codling moth larvae from near flower strips could be predator induced.