Investigating the dynamics of the rose aphid population on different rose cultivars and the biodiversity of its predators in Mashhad

The L. rosae Macrosiphum moth is considered one of the most important pests of roses in Iran and other parts of the world. Population changes of this moth on six different rose cultivars were investigated with weekly sampling from late March 2012 to late March 2013. At the same time, the biodiversity of arthropod predators of rose moth at the study stations was calculated using Shannon-Wiener biodiversity indices and Pillau evenness. The results showed that rose aphid had two population peaks during the growing season on all 6 cultivars in spring and autumn. Statistical analysis of the data showed that the average number of aphids on the evaluated rose cultivars had significant differences.

Blessing and Iceberg cultivars had the highest and lowest infestation of rose aphids in the sample, with an average density of 62/254±43/3 and 12/656±10/2 aphids, respectively. The cultivars Josephine Bruce (with an average density of 245.56±30.9 aphids), Piccadilly (with an average density of 789.52±44.1 aphids), Miniature (with an average density of 121.41±24.8 aphids), and Fairy (with an average density of 598.35±24.9 aphids) were ranked between the two cultivars Blessing and Iceberg, respectively. Calculation of the Shannon-Wiener biodiversity index of rose aphid predators on different cultivars showed that the highest value of this index (1.65) was estimated for the Josephine Bruce cultivar on 10/02/2013 and the lowest value of the index (0.38) was estimated for the Iceberg cultivar on 29/09/2013. Also, the lowest value of the Piloe uniformity index was estimated for the Josephine Bruce cultivar (0.49) on 17/02/2013 and the highest value was estimated for the Iceberg cultivar (0.98) on 29/09/2013. Among the predators of rose aphids, rose flies with seven species and an abundance of 91.38 and ladybugs with eight species and an abundance of 12.30 were the most dominant rose predators, respectively, and other rose predator species were ranked after these two families.