Repellency effects of four Ocimum spp leaves and oils against brown planthopper, Nilaparvata lugens (stal.)

Abstract

Repellency test against freshly emerged BPH adults was carried out with four essential oils and fresh leaves of Ocimum spp in six armed olfactometer to know repellency/attractancy in laboratory conditions at Indian Institute of Rice Research, IIRR, Hyderabad, Telangana during 2016-2017. Repellency test with leaves and essential oils of four Ocimum spp against female BPH the obtained data showed that highest repellency percentage was recorded in Ocimum gratissimum both in leaves and essential oils at time interval of 10, 20, 30, 40, 50, 60 minutes after release of BPH female. The average repellency percentage of BPH with leaves was 87.37% which is significant repellency compared to control 48.45% followed by O.sanctum 77.76% O.basilicum 71.36%, O.americanum 61.29%. The average repellency percentage of BPH with essential oils was 88.31% which is significant repellency compared to control 29.50% followed by O.sanctum 76.84% O.americanum 58.61%. O.basilicum 58.23%. The highest repellency percentage was recorded in O.gratissimum in both leaves as well as essential oils, the highest repellency percentage was due to there may possibility of presences of odd chemical compounds like eugenol, methyl chavicol, methyl eugenol in Ocimum gratissimum plant.