ABSTRACT
The rose aphid, Macrosiphum rosae (L.), is one of the most important pests on rose plants (Rosa spp.) with a worldwide distribution. As resistance indices, the development, survivorship, and reproduction of this aphid were evaluated on 10 rose cultivars, including Bella Vita, Cool Water, Dolce Vita, Maroussia, Orange Juice, Pinkpromise, Roulette, Tea, Valentine, and Persian Yellow in laboratory at 25 ± 1°C, 65 ± 5% relative humidity, and photoperiod of 16:8 (L/D) h. Rose aphid successfully survived on all 10 rose cultivars, although mortality rate was higher on Tea and Bella Vita. The number of offspring per female differed significantly among the tested rose cultivars, and ranged from 9.2 on Tea to 38.7 nymphs on Orange Juice. Population growth parameters were significantly affected by rose cultivars. The longest mean generation time (T) was observed on Bella Vita (14.8 days) and Tea (14.7 days) and the shortest on Orange Juice (10.0 days). The net reproductive rate (R 0 ) ranged from 6.9 on Tea to 33.2 nymphs on Orange Juice cultivar. Correspondingly, the highest value of intrinsic rate of increase (r m ) was observed on Orange Juice (0.348 day-1) and lower values on Tea (0.131 day-1) followed by Bella Vita (0.154 day-1). Cluster analysis of all the measured parameters of rose aphid on different rose cultivars revealed that Tea and Bella Vita were relatively resistant to M. rosae. These findings could be useful in developing an integrated pest management (IPM) program for this aphid in urbanized areas and commercial rose potting.
Subject(s)
Aphids , Reproduction , Rosa , Animals , Female , Nymph , Population Dynamics , Population GrowthABSTRACT
The black bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae), is one of the important pests of sugar beet. The relative impact of resistance, including antibiosis and antixenosis of five sugar beet cultivars (Doroti, Perimer, Pershia, Rozier and 006) on A. fabae was studied under laboratory conditions using clip cages. The antibiosis test was based on life table parameters. Significant differences on developmental time, mean number of nymphs/aphid/day, fecundity, and adult longevity of A. fabae were found across tested sugar beet cultivars. In addition, there were significant differences among the sugar beet cultivars for population growth parameters such as the intrinsic rate of natural increase (r m ), net reproductive rate (R 0), finite rate of increase (λ), doubling time (DT), and mean generation time (T) of A. fabae. The highest and lowest (r m ) values were observed on Pershia (0.449 nymphs/female/day) and Perimer (0.358 nymphs/female/day), respectively. No significant differences were found for the preference of the black bean aphid, and antixenosis had no effect on resistance against this aphid. As a result, our findings showed that the Pershia cultivar was a relatively susceptible host plant. Two cultivars (Perimer and Rozier) were relatively resistant to A. fabae, which could prove useful in the development of IPM programs for this aphid in sugar beet fields.