Abstract: 【Aim】 The pink stalk borers, Sesamia spp., are the most destructive pests of sugarcane, Saccharum spp., in Iran and other countries including India, Pakistan, Sri Lanka and Japan. The larvae of Sesamia bore into the stalk and cause damage to stalks by reducing weight and sugar content as well as juice quality. For management of stalk borers, several control options are used. Using resistant varieties is an effective tool which has no harmful impact on environment. This study aims to evaluate the resistance of commercial varieties to stalk borers. 【Methods】 The trials were conducted following a randomized block design with five replications in two successive years 2013-2014 and 2014-2015 at Salman-Farsi Agro-industry Farms, Ahwaz, Iran. The eight varieties CP69-1062, CP48-103, CP57-614, CP73-21, SP70-1143, IRC99-01, IRC99-02 and L62-96 were used. Prior to harvest, 20 whole stalks were randomly collected for Sesamia spp. damage assessments. Percent of stalks damaged, percent of internodes bored (IB), number of exit holes, number of live Sesamia spp. and moth production (MP) per hectare of each variety were recorded. 【Results】 There were significant differences in measured parameters among cultivars. Based on the percent of internodes bored and moth production index, L62-96 was the most susceptible variety among the tested varieties (14.58% IB, 95 200 MP/ha in 2014 and 16.76% IB and 111 300 MP/ha in 2015) followed by CP69-1062 and CP48-103, and CP57-614 was the most resistant cultivar in both years (1.24% IB, 8 400 MP/ha in 2014 and 1.02% IB, 7 000 MP/ha in 2015). 【Conclusion】 We proposed that cultivation of susceptible cultivars should be confined and other control strategies must be incorporated with varietal resistance for management of stalk borers in susceptible varieties.  

Key words: Sesamia spp., Saccharum spp., damage assessment, varietal resistance, juice quality, integrated pest management