Population Trends of Woolly Apple Aphid, Eriosoma lanigerum and its Parasitoid, Aphelinus mali on two Apple Cultivars in Jordan

The population trends of Woolly Apple Aphid (WAA), Eriosoma lanigerum Hausmann (Homoptera: Aphididae) and its parasitoid, Aphelinus mali Haldeman (Hymenoptera: Aphelinidae) were studied on two apple cultivars, Fuji and Golden Delicious during 2006-2007. Results indicated that even though both Fuji and Golden Delicious were grafted on the same rootstock, MM.106, but both of them showed variability in the populations of WAA. The edaphic populations of WAA recorded on Fuji during winter while roots of Golden Delicious did not sustain any form of WAA. Generally, aerial aphid colonies on both Fuji and Golden Delicious have been seen throughout the year except in severe winters from January to the end of March. Peak abundance of aerial populations on Fuji was 240 colonies per tree in November 2006 and 225 colonies per tree in August 2007. Peak abundance of arboreal populations in Golden Delicious was 43 colonies per tree in November 2006 and 33 colonies per tree in July 2007. Fuji sustained higher numbers of WAA than Golden Delicious throughout the years of study. The percentages of mummified WAA were very low (less than 10 %) during 2006-2007, but always higher on Fuji than on Golden Delicious