Resistance to sugar beet root aphid, Pemphigus fuscicornis (Hem.: Aphididae), in nine sugar beet genotypes at laboratory conditions

Sugar beet Root aphid Pemphigus fuscicornis (Koch) (Hem.: Aphididae), is an important sugar beet pest (Beta vulgaris L.) in many countries. Recently, this pest has attacked sugar beet fields in Borujerd, north of Lorestan province, Iran. In this research, resistance to sugar beet root aphid was evaluated in nine sugar beet genotypes, under laboratory conditions in a randomized complete design during 2001-2002. At first, sugar beet seeds were planted in a small plot, and were grown for about 50 days, and then plants were transplanted into a peat-vermiculite mix in pots. Five reproductive aphids were placed on the root mass before being transferred into the pot. The pots were transferred to an incubator (set at 20±2ºC and 16h artificial light and 8h dark). Forty days after infestation, the incubator temperature was suddenly decreased to 5ºC and then the aphids were counted. Results showed that, variety of Simin1 was highly susceptible, BR1 Karaj was moderately susceptible and two varieties of Polyrave and Dez Elit were moderately resistant.