Effect of essential oil from citronella and alfazema on fennel aphids Hyadaphis foeniculi Passerini (Hemiptera: Aphididae) and its predator Cycloneda sanguinea L. (Coleoptera: Coccinelidae)

Abstract

The essential oil of plants is used as an alternative to pesticides for the control of aphids. We study the effect of the essential oils of citronella and alfazema on aphid populations in the laboratory and in the field. We also investigate the effect of these oils on the behavior of the aphid's principal predator the ladybug. The results show that alfazema is highly effective, more so than citronella. A 1% concentration of alfazema oil is more effective in killing aphids than the same concentration of citronella. Alfazema oil has the further advantage that it is attractive to ladybugs and is less lethal to fennel flowers. © 2006 Science Publications.