GROUND COVER MANAGEMENT IN CITRUS AFFECTS THE BIOLOGICAL CONTROL OF APHIDS

The citrus aphids Aphis spiraecola Patch. and Aphis gossypii Glover (Hemiptera: Aphididae) are key pests of citrus clementine in Spain. A rich complex of natural enemies (NE) exploits these two species. However, NE usually colonize citrus trees once aphid populations have exceeded economical thresholds. Hence, successful biological control should be based on anticipating the arrival of NE. Recently, our group has found that citrus orchards with a ground cover of grass (Poales: Poaceae) had less aphids per colony and these colonies lasted shorter than those colonies found in orchards with bare soil management. These differences were attributed to an earlier appearance of aphid NE in the grass cover which attracted NE to the citrus orchard. This early appearance of NE contributed to a successful control of aphids in the canopy.