Seasonal Population Fluctuations of the Rose Aphid, Macrosiphum rosae (L.) (Hemiptera: Aphididae), on Different Cultivars of Roses and Nastaran

Rose is one of the most important ornamental shrubs of the world because of its durability, long period of flowering, different cultivars and its beauty. The rose aphid, Macrosiphum rosae is the most important pest of the rose which causes significant economic damage annually. In order to compare four rose cultivars including Black Magic, Caramba, Noa and Good Life, and a wild rose, Nastaran, infested with rose aphid, a split-plot in time experiment was arranged in randomized complete block design layout with three replications, in Isfahan (Iran) from February 2004 to March 2005. The infestation levels of roses with the rose aphid and its seasonal fluctuations were determined by weekly sampling. Analysis of data showed that there are significant differences (P<0.01) between cultivars. Noa (with pink flowers) has the highest infestation of rose aphid (with average 23.12  ± 0.036 aphids) and Caramba (with yellow flowers) has the lowest infestation (with average 6.46  ± 0.036 aphids). The wild rose, Nastaran, showed low infestation (with average 8.76  ± 0.036) as well. Different sampling times also showed significant differences (P<0.01). There was a significant interaction (P<0.01) between cultivars and sampling date, such that reactions of cultivars to aphid (nymphs, adults and total) were not similar in different sampling dates. Seasonal fluctuations of the rose aphid showed two peaks in a year, in May and December. Activity of the rose aphid in spring which coincides with rapid growth and tenderness of rose foliage causes severe fading and inhibiting of floral opening.