Field biology of woolly apple aphid, Eriosoma lanigerum (Hausmann), and its natural enemy, Aphelinus mali (Haldeman), in apple orchards in the Western Cape Province
The seasonal cycles of Eriosoma lanigerum (Homoptera: Aphidiae) and its natural enemy, Aphelinus mali (Hymenoptera: Apelinidae), were studied in the Western Cape Province region of South Africa. Crawlers of E. lanigerum migrated from the roots into the apple trees during spring to initiate above-ground colonies. Population numbers peaked at the end of summer. Aphelinus mali became active from February until June. Eriosoma lanigerum numbers declined with the onset of winter but a few colonies remained on apple trees during winter.